I've never been a fan of EGR's especially in diesel applications. I can't stand the thought of all that soot being recirculated. I along with most others believe that the EGR will reduce the engines life.


I asked for information in the ask the techs forum pertaining to the EGR. http://dieselplace.com/forum/forum_posts.asp?TID=12356&PN=1 GMCSID provided me with the information I was looking for. From what I can tell it looks like a stepper motor is used to open the EGR upon the ECM's request and a spring closes the EGR valve when it is not called upon. So my thoughts are that when the engine is off, the EGR is closed. If I am correct, if we unplug the EGR while the engine is not running the EGR should be closed and not be able open under any circumstances short of a spring failure. This would result in an ideal situation of no Exhaust gasses be recirculated at all.


I unplugged my EGR about 600 miles ago to test the results. So far I have no check engine light although I am sure there will be a couple codes set such as insufficient EGR flow etc. Now I can't say for sure but my fuel mileage seems to have improved. I gained about 1.5mpg running empty on one tank. Nothing changed in my driving routine but my truck is still under 2000 miles so it might just be breaking in that brought on the increase. It also seems to have better throttle response resulting from seemingly quicker turbo spool up times. I have no way to measure this so it might just be a figment of my imagination brought on by hopeful thinking. My theory (which is most likely totally wrong) is that there might be a decrease in spool up time resulting from ecm not having to wait for the EGR to close before allowing the turbo to spool up.


Test at your own risk. I am not to be held responsible from any negative side affects or damage that may result. http://dieselplace.com/forum/smileys/Geek.gif


I might be totally off the wall here. I would really like to hear any opinions, comments or related experiences.

Where the heck is it?--I'll unplug mine too, just to see what happens.

By the engine oil dipstick under the intake. It's a round plastic housing with a plug with 5 wires plugged into it.


Here is a basic drawing of it.


http://service.gm.com/engif/000/001/401/1401821.gif

Please let me know if you see a decrease in turbo spool up times.

I am gonna do this too.....awesome thinking and post max power!http://www.dieselplace.com/forum/smileys/Clap.gif

Max Power,


Did you have any change in your EGT's when you did this?





Rob

Doesn't look like it.

Well, I'm not ready to try it just yet, but I'm definitely interested. Something tells me to wait and see what happens. I think once winter rolls around you will see some codes set off, as you suggest Max Power.


I think it is a good idea, but I will wait and see for a little while. Heck, I've got over 11,000 EGR miles on it now, what can a few more hurt since I'm not putting many miles on it right now.


You could do a rough test on it if you had a G-Tech (or whatever they're called nowadays), or a Friend with a stopwatch. If there is a noticeable difference you should be able to measure it within a tenth or two I would think.


Start with the EGR off, do three runs to 60 MPH (or 100 KpH), then reconnect it, and do the test again. You would probably have to do it on a fairly cold day (do those exist in August?) to see if there is a measurable difference.


I don't like the soot racing around either, so if this turns out good, I'll do it. Hopefully it will work.


Does the EGR work all the time or just until the beast warms up to normal operating temperature? I'm kinda fuzzy on the whole EGR thing.


Thanks,
Dennis

I wonder if the sensor is in that bundle as well. Five wires seems a lot for just a stepper motor. If that is the case, you won't get any codes either.


Dennis

I really don't know for sure but I would assume that 4 out of the 5 wires are for the stepper motor and the 5th is likely a stepper motor position sensor. At least that is similar to other stepper motors I have experience with.

I should be able to tell you for sure on the 11th. The Helms tech manual is supposed to show up then.


Dennis

Its quite normal that the trottle response and turbo spool up time improves when disableing the egr. The exhaust gas is no longer "wasted" going back through the egr pipe to the intake. All the exhaust gases are now available driving only the turbocharger. The egr principle is simply like this: A part of the exhaust gases are routed back to the intake and burned again resulting in reduced NOX. The flow is controlled via the PCM depending on load and rpm.

I did remove the egr many years ago on my turbo diesel landcruiser with the same results as MP. Much cleaner intake (the soot from the exhaust no longer reaches there) and quicker response! You also get cleaner exhaust gases with less soot since the dirt is not recirculated all the time but NOX will go up. With egr NOX is far better but soot much worse so there is a trade off, but both values are half way good. Without egr soot will decrease a lot but NOX will go up the same time. I feel for our nature it makes no real difference if I produce lots of soot or lots of NOX, both are bad! But for the intake valves, cleaner burning engine etc. its much better without egr.
Good to know that on a modern engine like the dmax there is still an easy way of improvement thanks MP!
So I will disconnect it as soon I have my truck - I have ordered today my 2500 HD CC SB 4 x 4 GMC in dark blue - can't wait to get it (after waiting more than 3 years...long story!)

Update: another 200 miles. Fuel mileage is definately increasing. Finally got to do some city driving. Throtle response is definately a lot better around town. Cruising down the highway with the cruise set at 2000rpm the truck is soooo much queiter. You absolutely can not hear any diesel clatter. The only thing you can here is the turbo. So far, no regrets!

I should be able to tell you for sure on the 11th. The Helms tech manual is supposed to show up then.


Dennis






IF you can scan a wiring schematic of the EGR that would be fantastic! Thanks

I can heare mine ajusting when I'm sitting at idle with the big pipe so I know something is going on. I'm going to try the unplug method. I'll let you know what happens.

hear

I have the wiring diagram but I'm having a hard time posting it. Can someone help?

<H1 style="MARGIN: auto 0in">DTC P1404</H1>
<A name=ss1-1369752></A>[/url]
<H5 style="MARGIN: auto 0in">Circuit Description (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1369752&amp;evc=sm&amp;pubid=437&amp;cellI d=84038&amp;mspsdsubkey=3243#ss1-1369752ss1-1369752)</H5>


The engine control <st1:PersonName>m</st1:PersonName>odule (ECM) uses the exhaust gas recirculation (EGR) position sensor to deter<st1:PersonName>m</st1:PersonName>ine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference circuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position, is sent fro<st1:PersonName>m</st1:PersonName> the sensor to the ECM through the EGR position sensor signal circuit. The ECM co<st1:PersonName>m</st1:PersonName>pares the actual EGR position with the desired EGR position when the EGR valve is co<st1:PersonName>m</st1:PersonName><st1:PersonName>m</st1:PersonName>anded open or closed. If the ECM detects a difference between the learned closed position and the co<st1:PersonName>m</st1:PersonName><st1:PersonName>m</st1:PersonName>anded closed position for a calibrated a<st1:PersonName>m</st1:PersonName>ount of ti<st1:PersonName>m</st1:PersonName>e, DTC P1404 sets.
<A name=ss2-1369752></A>
<H5 style="MARGIN: auto 0in">DTC Descriptor (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1369752&amp;evc=sm&amp;pubid=437&amp;cellI d=84038&amp;mspsdsubkey=3243#ss2-1369752ss2-1369752)</H5>


This diagnostic procedure supports the following DTC:


DTC P1404 Exhaust Gas Recirculation (EGR) Closed Position Perfor<st1:PersonName>m</st1:PersonName>ance
<A name=ss3-1369752></A>
<H5 style="MARGIN: auto 0in">[url="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1369752&amp;evc=sm&amp;pubid=437&amp;cellI d=84038&amp;mspsdsubkey=3243#ss3-1369752ss3-1369752"]Conditions for Running the DTC (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1369752&amp;evc=sm&amp;pubid=437&amp;cellI d=84038&amp;mspsdsubkey=3243#ss3-1369752ss3-1369752)</H5>
<UL =disc>
<LI class=MsoNormal style="MARGIN: 0in 0in 0pt; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l1 level1 lfo1; tab-stops: list .5in">DTCs P0642 and P0643 are not set. </LI>
<LI class=MsoNormal style="MARGIN: 0in 0in 0pt; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l1 level1 lfo1; tab-stops: list .5in">The ignition is ON for <st1:PersonName>m</st1:PersonName>ore than 0.5 seconds. </LI>
<LI class=MsoNormal style="MAR

Action Taken When the DTC Sets - California (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1369752&amp;evc=sm&amp;pubid=437&amp;cellI d=84038&amp;mspsdsubkey=3243#ss5-1369752ss5-1369752)
<UL ="disc">
<LI class=MsoNormal style="MARGIN: 0in 0in 0pt; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l3 level1 lfo3; tab-stops: list .5in">The control <st1:PersonName>m</st1:PersonName>odule illu<st1:PersonName>m</st1:PersonName>inates the <st1:PersonName>m</st1:PersonName>alfunction indicator la<st1:PersonName>m</st1:PersonName>p (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
<LI class=MsoNormal style="MARGIN: 0in 0in 0pt; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto; mso-list: l3 level1 lfo3; tab-stops: list .5in">The control <st1:PersonName>m</st1:PersonName>odule records the operating conditions at the ti<st1:PersonName>m</st1:PersonName>e the diagnostic fails. The first ti<st1:PersonName>m</st1:PersonName>e the diagnostic fails, the control <st1:PersonName>m</st1:PersonName>odule stores this infor<st1:PersonName>m</st1:PersonName>ation in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control <st1:PersonName>m</st1:PersonName>odule records the operating conditions at the ti<st1:PersonName>m</st1:PersonName>e of the failure. The control <st1:PersonName>m</st1:PersonName>odule writes the operating conditions to the Freeze Fra<st1:PersonName>m</st1:PersonName>e and updates the Failure Records. </LI>[/list]
Sooo... It sounds like the California trucks will illuminate the SES light?? Does storing the information in a different location in the ECM make for a tougher time with the dealer? I would like to unplug, but don't want to create a problem with the dealer if I need warranty work. Any thoughts from the techs?

I wouldn't be surprised if California trucks turn on the light when disconnected. It almost sounds like they want us non california users to disconnect it. Why else would they only have cali trucks turn on the MIL?

I wouldn't worry about the dealer. Just tell them you unplugged in once because you thought it was making noise or something. If they see the codes and know why they are there they won't do anything about it IMO.

Before bringing the truck to the dealer just plug everything back like it was before. NOBODY could proove that it was disconnected even there is a code set - it could be a malfunction of the egr circuit somewhere...

Any thoughts on the turbo pressure regulation via egr if thats permanents closed?

I will give it a try also! Thanks MP!


I will be heading home from a short vacation this weekend, to my surprise I got 19.1 mpg's (18.6 on the DIC) on my way out here! I will disconnect for the trip home and see what I get and will post the results tomorrow...

I'm unplugging mine right after I type this.....

Hello everyone,


New guy here. I just unpluged mine. Thanks for the info! Just a thought, wonder if there will be long term problems with the cat, with the added soot and all? Any imput?


Great forum, this is only my second diesel truck and the first was a stock powerstroke. I have the power bug and will start saving my pennies for the upgrades needed for the perma-grin. Plaese bear with me because I'm sure to be asking more questions.


Thanks, Rob

Hmmm, difference between Kalifornia and Federal. This raises a question. If I move from Kalifornia to another state how can I dump the Kalifornia program for a federal progrom? New computer? reflash?

Jim

IdahoRob,
if you unplug your egr there will be LESS soot, better for the cat, also better for the engine (less dirty intake valves...). Only bad thing is more pollutant NOX and maybe some turbo pressure regulation issues since this truck has no more bypass valve for excessive turbo pressure, don't know if the vane regulation is enough or the egr is also used to regulate the excessive turbo pressure - that can only be answered by the gm diesel techs here on this forum...

Max power, what are your thoughts on a block off plate where gasket #2 is in the diag. for us cali boys? Are there any other sensors that detect actual flow of the egr or is it just looking at motor position? Should also take some of the heat load off the coolant system. A person surley would'nt run a pipe from his rear end to his mouth and breath exhaust gasses, I feel the same way about my motor!!! lolhttp://www.dieselplace.com/forum/smileys/HiHi.gif Good post thanks Mark

socaldieseltech,
looks like the circuit simply compares actual and ref positions of the egr valve itself via the pos. sensor but NOT the actual flow of air through the egr.
This means there is a "fairly easy" solution without tempering with that egr at all (so no codes should be set). The pipe connecting the exhaust to the intake (with the egr valve in between) just needs to be closed at air intake side with some kind of metal plate. I have done the same many years ago with my 2 Landcruisers with the 4.2 ltr. inline six diesel. Worked like a charm!
That way the root cause of the "egr problem" is solved and nobody will even notice a small 1/8 inch thick (or thinner) metal plate at all!
Since I do NOT have my truck yet I don't know how the plate should look like.
Happy modifyingEdited by: mahalkita

So far so good

Just disconnected mine,


Noticed that when I blip the throttle, I get a nice puff of soot out the tail pipe. Any one else notice that?


It didn't do that before, so I can only assume that with the EGR connected it was moving that soot into my engine.


Next step may be to remove the cat,





Rob

Howdy everyone,

I'm new here, and this is my first diesel. Great forum for information or just laughs, really glad I found this place.

Just tried unplugging it myself, and no codes (I am in so cal). It may just be manifesting it, but it seems that the RPM is a tad higher, can anyone confirm this?

Other than that, it seems much more responsive from idle and the turbo spools up a bit faster. Definately smell the exhaust more so now, it is of the stinky diesel, not as much of that lemony smell anymore.

Just a thought, could problems with wishy washy codes all together be a direct correlation of where the truck was mfgr'd?

Max Power,


I'll be happy to scan and post the circuit once the book comes in. That is, if someone else doesn't beat me to it.


Dennis

I'm unplugging mine today. I already removed the cat so we'll see if this improves anything. The SES light came on when I first removed the cat but no longer comes on. At least I can put everything back if I need to go to the dealer for any work.

socaldieseltech,
looks like the circuit simply compares actual and ref positions of the egr valve itself via the pos. sensor but NOT the actual flow of air through the egr.
This means there is a "fairly easy" solution without tempering with that egr at all (so no codes should be set). The pipe connecting the exhaust to the intake (with the egr valve in between) just needs to be closed at air intake side with some kind of metal plate.

Neat idea. One question. Has anyone taken this thing off? Looks like it might be bit of a PITA. Helms manuals on the way.

JimEdited by: jholly

jholly,
like I mentioned before I have done this only on my 2 diesel Landcruisers before without any problem. I do not have my truck yet so I cannot tell how to do it, but I assume no big deal!
What kind of Helms manual you are getting?
Maybe Socaldieseltech could tell us what manual to get, seems he is "sitting on the source" of all necessary information.

What kind of Helms manual you are getting?
Maybe Socaldieseltech could tell us what manual to get, seems he is "sitting on the source" of all necessary information.

Frank,

The service manual from Helms and as I understand it, they are the factory service manuals. They are about the only manuals I know of.

Jim

For those of you trying this it would be best to let the truck sit overnight, start engine and then shutoff. Go under hood and disconnect the plug. The reason for doing it this way assures the it's closed before disconnect. It is diabled when the engine cool temp is cold or when at full throttle so I doubt it will make any more power but it may well increase throttle responce.

Jim,
thanks for the info. How to get those Helms Service Manuals - directly from GM?

Frank

It is a spring return so shouldn't it always return to the closed position?

Diesel Tech, can you think of any negative aspects to doing this?


My current tank of fuel is going to be my best tank so far by a long shot. It should be right up there with what I was getting out of my LB7. http://www.dieselplace.com/forum/smileys/Big Smile.gif

Just studied a book about turbo charger construction. It was mentioned that a bypass valve is not required with a vane regulated turbo and all the pressure can be regulated via the vanes. So IMHO there should be no negative effect not using the egr at all, only less fuel wasted (better for our nature), cleaner intake (you will be surprised how much black sludge deposits will build up on your intake after 100 K miles or so with all the soot going over it - not good....and of course better trottle response!
But only a real diesel specialist can answer that question properly.

2005 GMC 2500HD L?? CCSB SLT 4x4 Dark Blue Metallic ordered

Update:


Disconnected mine before my trip home from vacation (256 miles) it seemed to help. The throttle response was better; my mpg's were better even though I was bucking the wind all the home.


I have a new noise from this or I believe it is from this, but when I pulled the tuck into the garage to park it, I let it cool down a little before I shut it off and when I shut it off I got a "gurgle" sound from the engine so I started it back up again and shut it off and it did it again. I let it sit for about 2 minutes tried it again with the hood open to get a better listen and when I shut it off it did not do it that time. I am pretty sure it was coming from the egr tube because the "gurgle" sounded like it was in a tube.


Has anyone heard this since they have disconneted their's?


My truck had sat overnight before I did this so not sure if this is good or bad thing to have happen but something from the heat I would guess??? Maybe need to look at closing the tube off completely...

Coolant gurgle? Try plugging the EGR back in and see if it still gurgles. I think you are probably just being too critical because you changed something. Chances are it will do the same thing with the EGR plugged in.

It is possible it could have been a coolant gurgle but I have not heard this before. It just sounded like a emtpy tube sound. I am going to leave it unplugged for now but I might try some testing but I need to do it when the motor is hottest because it didn't do it after it sat for those couple of minutes

I think dmaxhd is right with the tube sound (hollow tube sound like a gurgle). I have heared something like that also when I first disconnected the egr (vacuum) at my Landcruiser. The intake return tube is still open to the egr valve (which is now closed all the time because the connector is removed). Therefore I recommend to close the connection at the air intake with a metal plate - the noise should go away. But anyway its not a bad sign, just some "normal noise" which should not be too annoying.
Just my 2C

Jim,
thanks for the info. How to get those Helms Service Manuals - directly from GM?

Frank
Frank,
www.helminc.com ... $135 for the set, add $50 for the tranny book

JimEdited by: jholly

It will interesting to hear when someone makes a plate to close their system because I will probably want to do it myself but I would want to make sure we close it off at the right place.

I might make a plate. I'll try to spend some time on it shortly.

<H1 style="MARGIN: auto 0in">Exhaust Gas Recirculation (EGR) Syste<st1:PersonName>m</st1:PersonName> Description</H1>


The Exhaust Gas Recirculation (EGR) Syste<st1:PersonName>m</st1:PersonName> is used to reduce the a<st1:PersonName>m</st1:PersonName>ount of nitrogen oxide (NOx) e<st1:PersonName>m</st1:PersonName>ission levels caused by high co<st1:PersonName>m</st1:PersonName>bustion te<st1:PersonName>m</st1:PersonName>peratures. At te<st1:PersonName>m</st1:PersonName>peratures above 1,371°C (2,500°F), oxygen and nitrogen co<st1:PersonName>m</st1:PersonName>bine to for<st1:PersonName>m</st1:PersonName> oxides of nitrogen (NOx). Introducing s<st1:PersonName>m</st1:PersonName>all a<st1:PersonName>m</st1:PersonName>ounts of exhaust gas back into the co<st1:PersonName>m</st1:PersonName>bustion cha<st1:PersonName>m</st1:PersonName>ber displaces the a<st1:PersonName>m</st1:PersonName>ount of oxygen entering the engine. With less oxygen in the air/fuel <st1:PersonName>m</st1:PersonName>ixture, the co<st1:PersonName>m</st1:PersonName>bustion pressures are reduced, and as a result, co<st1:PersonName>m</st1:PersonName>bustion te<st1:PersonName>m</st1:PersonName>peratures are decreased, restricting the for<st1:PersonName>m</st1:PersonName>ation of NOx.


The EGR valve <st1:PersonName>m</st1:PersonName>otor is a direct current (DC) stepper <st1:PersonName>m</st1:PersonName>otor utilizing a wor<st1:PersonName>m</st1:PersonName> gear that extends fro<st1:PersonName>m</st1:PersonName> the <st1:PersonName>m</st1:PersonName>otor to push on the EGR valve ste<st1:PersonName>m</st1:PersonName>. The wor<st1:PersonName>m</st1:PersonName> gear is not attached to the valve ste<st1:PersonName>m</st1:PersonName>, and can only force the valve open. A return spring is used to force the valve closed.


The <st1:PersonName>m</st1:PersonName>ass air flow (MAF) sensor signal is used by the engine control <st1:PersonName>m</st1:PersonName>odule (ECM) to detect the proper a<st1:PersonName>m</st1:PersonName>ount of EGR flow. One EGR flow test is perfor<st1:PersonName>m</st1:PersonName>ed per ignition cycle. The ECM will close the EGR valve for 5 seconds, then open the EGR valve to 100 percent for 5 seconds. The ECM will then calculate the MAF difference and deter<st1:PersonName>m</st1:PersonName>ine if the proper EGR flow has been detected.
<A name=ss1-1369855></A>[/url]
<H5 style="MARGIN: auto 0in">[url="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1369855&amp;evc=sm&amp;pubid=437&amp;cellI d=84208&amp;mspsdsubkey=3243#ss1-1369855ss1-1369855"]Exhaust Gas Recirculation (EGR) System Operation (http://service.gm.com/servlets/BlobShtml?ShtmlFile=1369855&amp;evc=sm&amp;pubid=437&amp;cellI d=84208&amp;mspsdsubkey=3243#ss1-1369855ss1-1369855)</H5>

</v:stroke></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:

I think that what you guys have the right idea, but I'm surprised no DTC's have been set yet. The ECM is monitoring the EGR system, without a doubt. I'm sure DTC's will show, they'll just illuminate the MIL, no limp mode or things of that nature.


The <st1:PersonName>m</st1:PersonName>ass air flow (MAF) sensor signal is used by the engine control <st1:PersonName>m</st1:PersonName>odule (ECM) to detect the proper a<st1:PersonName>m</st1:PersonName>ount of EGR flow. One EGR flow test is perfor<st1:PersonName>m</st1:PersonName>ed per ignition cycle. The ECM will close the EGR valve for 5 seconds, then open the EGR valve to 100 percent for 5 seconds. The ECM will then calculate the MAF difference and deter<st1:PersonName>m</st1:PersonName>ine if the proper EGR flow has been detected.

socaldieseltech,
looks like the circuit simply compares actual and ref positions of the egr valve itself via the pos. sensor but NOT the actual flow of air through the egr.


See above post

Unplugged mine. CEL came on after a 2nd start up. Not sure if its for the EGR or the insufficient flow thingy. All I know is that my mpg went up to 19.6mpg on a 200 mile trip this afternoon. Heck I will drive around with the stupid light on to get this kind of mileage.

No light here. Odd that some do it and some don't.

My MIL light seems to have came on as well, after a 3rd cycle of the engine. Oh well, like emerick, I'll live with the light being on.

Diesel Tech,

Would a code being set via these conditions be reprogrammed to not fire under Tow Tune?

40 mi no light, seeems to smoke slightly more as throttle is applied. TTS tow tune, exhaust, and -cat makes it hard to judge an improvement in throttle response(already greatly improved), low speed throttle response may have improved slightly. Heading to Columbus,OH this weekend, I will check mileage and report the results 8/16.

PM me for more info


mahalkita wrote:

<TABLE cellSpacing=0 cellPadding=1 width="100%" bgColor=#999999>
<T>
<TR>
<TD>
<TABLE cellSpacing=0 cellPadding=2 width="100%" bgColor=#ffffff>
<T>
<TR>
<TD class=text>
What kind of Helms manual you are getting?
Maybe Socaldieseltech could tell us what manual to get, seems he is "sitting on the source" of all necessary information.</TD></TR></T></TABLE></TD></TR></T></TABLE>

pulled mine earlier, not enough driving yet to see a difference or not - but it did set a code right away after i drove away, p1404 - emissions related, i cleared it and next trip back to office set again... so by removing this are we at harm of doing any damage to the truck - it sounds like from what ive read above that it wont and its more than likely a better thing but want to make sure

There should be no damage done by this mod as long we can be sure the EGR is closed and not allowing anything through. I plan to dissasemble and see what I can see. http://www.dieselplace.com/forum/smileys/Cool.gif





You say that you set a code. Are you seeing a check engine light or just a code? I expected a code but as long as their is no check engine light it will not bother me. You are obviously not worried about emissions because you have no cat anyways. http://www.dieselplace.com/forum/smileys/Big Smile.gif

check engine light comes on and upon scanning for codes, i get the above mentioned code ? should i plug back in for time being or is it safe to assume its closed ?

I assume you are getting a check engine light because you have a california truck.


I am pretty certain it is closed. I just want to confirm for peace of mind. Even if it is not closed you aren't really worse off then you are with it connected because it would be open most of the time anyways.Edited by: Max Power

I've had mine unplugged for 4 trips now and about 75 miles....I CAN feel an improvement in spool up and less lag. No Check Engine light yet and so far impressed.....http://www.dieselplace.com/forum/smileys/Big Smile.gif

Mileage? Not enough miles yet?

My mileage is at 19.4 after about 265 miles of being unplugged. Check engine light still on.

so do you think it should be unplugged like dieseltech says to ensure it is closed or are we assuming that it is indeed closed ?

Not sure. IMO I think it should be closed either way. But diesel tech seems to think that might not be the case so that puts doubt in my mind. In my opinion if there is no power driving the stepper motor, it has to be close due to the fact that it has a spring to return it to the close position. So my thoughts are that even if you were to have it plugged in and fully open, as soon as you unplug it the spring should return it to fully closed. Of course I have not confirmed this by cracking it open and testing it. This is just what I gather from the GM information that my first post links too.


I'd love to be able to confirm this.

My mileage is at 19.4 after about 265 miles of being unplugged. Check engine light still on. Can you get the codes read to confirm that it is EGR related? It's funny some do it and some don't. I can understand (and expected) the california trucks but you are from NY. http://www.dieselplace.com/forum/smileys/Geek.gif

Update on the "gurgle" sound I heard...


I had my wife shut the truck off when I was under the hood and the sound was being echoed through the air intake like it was trying to gasp for air. I plugged the wire harness in quickly and started the truck back up and then shut it off and it did not make the sound. I am not worried about this but wanted to update....

Odd. A gurge sounds would indicate a liquid gurgling, right? So what is the liquid?

You are right MP, after hearing it closer I probably need to change the terminology from "gurgle" to something else. It sounded like it was trying to suck in air or trying to release air through the intake so I am not sure what to call it.

Max Power,


If the EGR motor uses a worm gear it may be possible to stay open when shutting down unless a signal is sent. Could it be possible that the EGR motor works in both forward and reverse?


I wonder if dmaxhd's sound is cylinder compression leaking past the valve on shut down


Jus thinkin out loud


Rob

If I unhook my EGR and I get a check engine light, will plugging it back in make the light go off or is it a trip to the dealer or what?http://www.dieselplace.com/forum/smileys/Confused.gif

The code will be there no matter what. Even if you don't set a light, you will still get a code. If you do get a light, after you plug it back in for a while the light will eventually go off.


If you're not sure about this mod, or don't know what you are doing don't do it. We are still very early in the testing phases. A few more miles with the EGR connected won't hurt anything until we get some stuff sorted out.

Unplugged mine yesterday and got the check engine light after 3 starts. Get some black smoke and possibly better spool up. Hard to tell. Have not driven it enough to know about mileage.

Max Power


Thanks for the advise, I will wait for an outcome.


Dan

My mileage is at 19.4 after about 265 miles of being unplugged. Check engine light still on. Can you get the codes read to confirm that it is EGR related? It's funny some do it and some don't. I can understand (and expected) the california trucks but you are from NY. http://www.dieselplace.com/forum/smileys/Geek.gif

NY trucks would have the Northeast emissions, NOT the Federal emisions. So would VT, CT, NH, ME, RI, MA.

Northeast emissions are mostly like CA, but not as strict on some things. Not surprising that a Northeast truck behaves like a CA truck on something major like the EGR.

The stepper motor is a by directional until, that why there are 4 wires. 2 drive the motor in the forward direction and 2 to reverse the direction. The spring is in the egr valve itself so when the stepper motor backs the worm gear out the spring pushes the valve closed. If the stepper motor had the worm gear out and the valve open when you unplugged it it will stay open until you plug it back in and the ECM commands it closed. This is why I let you know when to do it. As far as the codes go GM makes two sets of diagnostics code for the trucks and it depend on what state your in when the truck was sold as to what you get. California is no longer alone with the extra emissions stuff, there are 13 states with the same rules. Your truck will have a label under the hood that will state if you have Federal Emissions or Calif. and Northeast Emissions. Bet you can guess which ones will turn the light on and which ones will not.

http://www.dieselplace.com/forum/smileys/Clap.gif My hats off to you guys willing to take the risk with these kind of mods. I'm not mechanically smart enough to understand it, nor do I have the "b_lls" to try it myself with a $40k+ truck. Hope all goes well. I'll continue to follow the posts to see how it goes. http://www.dieselplace.com/forum/smileys/Geek.gif JJ

The stepper motor is a by directional until, that why there are 4 wires. 2 drive the motor in the forward direction and 2 to reverse the direction. The spring is in the egr valve itself so when the stepper motor backs the worm gear out the spring pushes the valve closed. If the stepper motor had the worm gear out and the valve open when you unplugged it it will stay open until you plug it back in and the ECM commands it closed. This is why I let you know when to do it. As far as the codes go GM makes two sets of diagnostics code for the trucks and it depend on what state your in when the truck was sold as to what you get. California is no longer alone with the extra emissions stuff, there are 13 states with the same rules. Your truck will have a label under the hood that will state if you have Federal Emissions or Calif. and Northeast Emissions. Bet you can guess which ones will turn the light on and which ones will not.


This sounds similar to GM's statement. That makes sense to me now.


The EGR valve motor is a direct current (DC) stepper motor utilizing a worm gear that extends from the motor to push on the EGR valve stem. The worm gear is not attached to the valve stem, and can only force the valve open. A return spring is used to force the valve closed.


I don't understand your theory on having 4 wires. 2 to forward and 2 to reverse as you state. If it truly is a stepper motor as GM claims it is, it can not work that way. Actually I don't know of any DC motor that would work that way. I am sure I am just misunderstanding you. I'm not saying you're wrong, I just don't understand.


If a stepper motor were to use 4 wires, one would be common between 3 fields and the other 3 would be the other end of the winding for the 3 individual fields. So - on the common and pulse + on field 1, then field 2 then field 3 would yield 3 steps and one complete revolution. To reverse, change the common to + and pulse - to field 3, 2, 1 and you have one complete reverse revolution.


IIRC there are 5 wires going into the stepper motor. This could mean 4 fields with the above principal to provide more precise smaller (1/4 rev) steps.


I need to dig into this further. This is strictly speculation on my part.


Irregardless of that, the principal of the return spring is still the same and you are correct, we need to be 100% certain that the EGR is completely closed. From the results that I and others are seeing, I would say that the EGR must be closed or very close to it.


I think a restrictor plate is still a good idea to make sure it is completly closed up.


Edited by: Max Power

Max Power,


I think your right about the plate, That is a common mod for closing off EGR operation. Then let the valve open and close to its heart content,


no light yet on mine,


Do you get a puff of soot when you give it a shot of throttle?





Rob

MP,

Here is a quick reference to a simplified unifilar stepper motor that uses 4 wires. Unifilar Stepper (http://www.ams2000.com/stepping101.html) This is most likely what is in the EGR. The fields are pulsed positive in sequence then negative to generate motion.

However, I don't think the statement that two wires are for forward and two are reverse is quite correct. More likely, two are pulsed first for forward and the other two pulsed first for reverse.

Diconnecing the EGR Stepper motor physically from the actual valve may be an option to avoid codes. Need to know more how the position sensor is attatched.

MP,

Here is a quick reference to a simplified unifilar stepper motor that uses 4 wires. Unifilar Stepper (http://www.ams2000.com/stepping101.html) This is most likely what is in the EGR. The fields are pulsed positive in sequence then negative to generate motion.

However, I don't think the statement that two wires are for forward and two are reverse is quite correct. More likely, two are pulsed first for forward and the other two pulsed first for reverse.

Diconnecing the EGR Stepper motor physically from the actual valve may be an option to avoid codes. Need to know more how the position sensor is attatched.

The only gotcha is the MAF measuring the flow with the valve open and close to determine it is working.

Jim

Max Power,


I think your right about the plate, That is a common mod for closing off EGR operation. Then let the valve open and close to its heart content,


no light yet on mine,


Do you get a puff of soot when you give it a shot of throttle?





Rob








I am running the juice and attitude so I'm not a good person to ask. Yes it does give a small light colored cloud when you stab it at idle.

Thanks fingers. I know how stepper motors work in my mind but it's hard for me to put down in writing.


I did some more testing this evening. I pulled off the stepper motor. Of course it is sealed so I couldn't get at the windings without doing some damage. The stepper motor worm was fully retracted and was not putting any force on the EGR valve at all. Therefor I know for a fact that mine was fully closed. http://www.dieselplace.com/forum/smileys/Big Smile.gif


DieselTech is correct in that the stepper motor operates in both directions. There is a spring on the stepper motor that pushes outward but not with enough force to actually move the stepper worm drive. I assume it is just there to keep tension on it. There is another spring that holds the EGR valve itself in the closed position. This spring is quite strong. There is enough force on that spring/valve to push the stepper motor worm back to it's fully retracted position. I did a simple test to confirm this. I pulled the stepper motor out as far as it can go without falling out. I then pushed it into place carefully and the worm pushed in and the EGR valve didn't move. It took a LOT LESS force to push the stepper motor worm in then it does to push the EGR in. This tells me without a doubt that when the truck is off, the EGR will push the stepper motor all the way back in and the EGR will be fully closed. So we have no worries there.

As for the California and other emission trucks discussed above, we need to determine if the reason that the light is being illuminated is because the ECM isn't seeing the stepper motor or if it is because the MAF isn't reading the correct flow. I assume it will be the latter which leaves them S^%# out of luck unless they don't mind the check engine light being on. No other damage should occur. If it is simply because it is not reading the position of the Stepper, it will be a simple solution. A restrictor plate would be the answer then.


As for us non high emission trucks. At this time I don't think I will go to the trouble of making a restrictor plate. My thoughts are that with the EGR valve closed, it is probably stopping 99.9 if not 100% of the exhaust gas flow back into the intake anyways. While this might not be perfect, it is definitely no worse off then I was with the EGR connected properly. So with the gains I am seeing, it is good enough for me.


I also hooked up the EGR back up for a quick blast. The turbo spool up and throttle response difference is definitely there. Not a doubt in my mind anymore. http://www.dieselplace.com/forum/smileys/Big Smile.gif I am now disconnected permanently unless I discover some really adverse affects down the road. ( I HIGHLY doubt it though).


So now I am going to find a way to seal up the stepper motor plug and the wire plug.

Here is a better pic to give you guys and idea of what I am talking about.



<TABLE>
<T>
<TR>
<TD align=middle>(1)</TD>
<TD align=left>EGR Valve Position Sensor</TD></TR>
<TR>
<TD align=middle>(2)</TD>
<TD align=left>EGR Valve Worm Gear</TD></TR>
<TR>
<TD align=middle>(3)</TD>
<TD align=left>EGR Valve Return Spring</TD></TR>
<TR>
<TD align=middle>(4)</TD>
<TD align=left>EGR Valve Head</TD></TR>
<TR>
<TD align=middle>(5)</TD>
<TD align=left>EGR Valve Stem</TD></TR>
<TR>
<TD align=middle>(6)</TD>
<TD align=left>EGR Valve Motor</TD></TR></T></TABLE>


http://www.dieselplace.com/forum/uploads/FZ4_1382620.gif

Have had mine unplugged two days now and no codes. Will let you know of any changes

Max Power: Have you or any of the other folks with the Federal Emmisions package (Non CA and Non Northeast) run a scan to see if any codes have been set after disconnecting the plug? (This is not the same as not lighting up the Service Engine Soon light.)

I understand that if you do not have a scanner, some of the parts stores (IE AutoZone, etc.) will do a free scan.

Thanks.

I haven't but I am sure that there will be a code for insufficient EGR flow which doesn't worry me at all. I will get my hands on a scanner asap.

Anybody here have a late 03 truck w/ the egr? I think mine was a Cali truck cause it used to have a cat. I do have the long sliver can but mine doesn't look like the illustration. Mine looks like it has some sort of vac thing on the end instead of the servo gear. No plug for me?http://www.dieselplace.com/forum/uploads/CCA_EGR_001p.jpg

http://www.dieselplace.com/forum/smileys/Question.gif Will eliminating the soot from being recirculated through the intake and re-introduced back into the firing chamber help minimize injector problems? I've seen other posts where the LLY's may be experiencing some injector issues http://www.dieselplace.com/forum/smileys/Shocked.gif , or are they totally separate and unrelated? JJ

Unplugged mine and so far so good. No codes, federal emissions on my truck (OK). There is a major inprovement in the way the truck drives. It feels more like my LB7 on take off and is much more responsive. I do not notice any more or less smoke but I am running a Juice with Attitude so I really cannot say with certaintly either way. I will know more about mileage in a few days.


I also notice a "swooshing" noise at shut down from the top of the engine. I would like to know what is causing the noise and if it is good, bad, or indifferent.


Thank for the tip Max Power I feel much better knowing that soot is not traveling back into my motor http://www.dieselplace.com/forum/smileys/Big Smile.gif!!

Diesel Techs, where are you? We need for you to weigh in on this swishing sound they're hearing. Could it be back-pressure blowing by the EGR when the engine is turned off since it seems to go away after restart and turn-off (OK, that might be a dumb question but it may get the discussion rolling!)? http://www.dieselplace.com/forum/smileys/Rock On.gifJJ

http://www.dieselplace.com/forum/smileys/Question.gif Will eliminating the soot from being recirculated through the intake and re-introduced back into the firing chamber help minimize injector problems? I've seen other posts where the LLY's may be experiencing some injector issues http://www.dieselplace.com/forum/smileys/Shocked.gif , or are they totally separate and unrelated? JJ


anyone with some info on this one ??

Now I'm really confused. My silver thingy says Tokyo Radiator. I looked them up on the net and it shows its a cooler for an egr? http://images.google.com/imgres?imgurl=http://www.tokyo-radiator.co.jp/seihin/photo/egr.jpg&amp;imgrefurl=http://www.tokyo-radiator.co.jp/seihin/egr.html&amp;h=220&amp;w=260&amp;sz=13&amp;tbnid=AmndDHD4jqQJ:&amp;tbn h=90&amp;tbnw=106&amp;start=4&amp;prev=/images%3Fq%3Dtokyo%2Bradiator%2B%26svnum%3D100%26h l%3Den%26lr%3D%26ie%3DUTF-8%26safe%3Doff%26sa%3DN (http://images.google.com/imgresimgurl=http://www.tokyo-radiator.co.jp/seihin/photo/egr.jpg&amp;imgrefurl=http://www.tokyo-radiator.co.jp/seihin/egrl&amp;h=220&amp;w=260&amp;sz=13&amp;tbnid=AmndDHD4jqQJ:&amp;tbnh=90 &amp;tbnw=106&amp;start=4&amp;prev=/images%3Fq%3Dtokyo%2Bradiator%2B%26svnum%3D100%26h l%3Den%26lr%3D%26ie%3DUTF-8%26safe%3Doff%26sa%3DN)


Remember mine is an 03 LB7. What the hell?

http://www.dieselplace.com/forum/smileys/Shocked.gifThe answer to the girgling question just might be in here. They mention the combination of the EGR, CAT and turbo creating backpressure. I got this off the dieselpage for the LLY. OK techies, do your stuff.
Cooled EGR: EGR flow is controlled by the LLY's brand new E60 ECM and digitally controlled EGR valve, with programming that takes into account the heat load imposed on the engine's cooling system by the hot exhaust gases. EGR flow can occur when IAT (intake air temperature) is above 41.5°F and with an engine temperature between approximately 140°F and 211°F. Terminating EGR flow above 211°F helps to preserve the cooling ability of the engine. The EGR stepper motor and control valve assembly are serviceable, and new OBD II diagnostic procedures allow the technician to monitor/test the operation of the EGR. EGR flow is disabled if any of the EGR related DTC's are set.http://www.thedieselpage.com/duramax/LLY01.jpg
The arrow near the top of the image on the left points to the stainless steel cylinder that is part of the cooled EGR system. Engine coolant is used to cool EGR flow. Exhaust gases are scavenged from the right side turbo exhaust inlet pipe, cooled by coolant flow, then injected into the intake manifold on the engine. The combination of exhaust restriction produced by the turbo, catalytic converter and exhaust system raise the exhaust backpressure to a level above intake manifold pressure. For now at least, EGR flow is not being routed through the intercooler.
Hope this helps! http://www.dieselplace.com/forum/smileys/Geek.gif

interesting info, thank you - what does it actually mean to us though ?

http://www.dieselplace.com/forum/smileys/Clown.gifDamn Tbone, I just ask the questions, answers are a different story. I just remembered reading on the dieselpage site something about the EGR. It may be that "the combination of exhaust restriction produced by the turbo, catalytic converter and exhaust system raise the exhaust backpressure to a level above intake manifold pressure" may have something to do with that "girgling" sound guys have been hearing. Is it possible I'm way, way, way, way out in left field, you betcha! http://www.dieselplace.com/forum/smileys/Confused.gifJust trying to get our brain cells engaged to resolve that issue. JJ

LOL - i know, thats just the way my brain works. I was just trying to re-confirm that this isnt something that will cause us problems that are not know at this time - thanks again

I really don't think that the gurgling sounds is a result of disconnecting the EGR. The only gurgling sound I hear can be duplicated with the EGR plugged in or not.


You have to remember we are not really doing anything drastic here. We are disconnecting the Stepper motor that pushes on the EGR valve. Nothing more. There are lots of times that you will start and shut off the engine under normal conditions (Stepper hooked up) and EGR will not cycle. So as far as I am concerned, there is nothing to go wrong or even change for that matter.

The other nice thing about this mod is that the engine should run cooler while towing. Some are complaining about there LLY's getting too hot while towing. Disconnecting the EGR should help keep everything cooler based on the following statement:



Terminating EGR flow above 211°F helps to preserve the cooling ability of the engine.


We are terminating EGR flow at all temperatures. http://www.dieselplace.com/forum/smileys/Big Smile.gif

http://www.dieselplace.com/forum/smileys/Thumbs Up.gif I noticed the Powerstroke 6.0 owners are doing the same thing. Damn the EPA, full speed ahead!http://dieselplace.com/forum/smileys/Evil%20Smile.gif I'm pulling the plug on mine tonight.


JJhttp://www.dieselplace.com/forum/smileys/Big Smile.gif

I disconected about 100 miles or so ago. No engine light. Mileage up over 1 mpg around town with a/c on. Thanks again for the great info.


RobEdited by: IdahoRob

Wow, what an interesting thread here! I have a Cali truck and am considering doing this. So, the steps to make absolutely sure that this valve is shut all the way is to:

*Leave truck sit overnight.
*Start in morning and then shut off to make sure EGR valve
is shut. Is this immediate or let it idle for X amount of
seconds/minutes?
*Disconnect EGR.
*Drive to test change made to engine.

hamsalad. You will be safe just unplugging it when the truck is off. But that procedure will work too.

Thank you for the quick reply, Max. I will be attempting this mod this evening and will report any codes or strange behavior!

All of this discussion has made me ask a question I have been wondering about for a while. I am assuming that the ECM controls the EGR. If this is true, then why would the Edge and other modules not just overwrite this output from the ECM and keep the EGR commanded closed. Or similarly, modules such as TTS or even other programmers would just overwrite this section of the programming and never command it to open. At the same time, they would also be reading the inputs from the EGR system, and could tweak them to be within limits, eliminating setting codes. Or, just adjust these limits altogether with a programmer so that you would never be outside of the acceptable range.


I may be way out in left field with this, but it seems like they found solutions to up the horsepower real quickly, and seem to have done it well. I just imagined that there would be a fix to the EGR by now also, since it is evident that so many people do not like having it. Anyone have any ideas on this? I imagine that it is way more complicated than I am making it sound, but it is just something I have been wondering about.

Mine has been disconnected for a few days...no engine lights yet...definitely a quicker spooling turbo and better throttle response. Thats the cheapest mod in the world and its definitely noticeable. MAX...thanks for researching this one...again wonderful post and info! This site is of great value for all Dmax owners and threads like this are why!http://www.dieselplace.com/forum/smileys/Rock On.gif

NOW ALL WE NEED TO DO IS FIGURE OUT HOW TO TRICK THE ECM SO I CAN TURN THE DAMN LIGHT OFFhttp://www.dieselplace.com/forum/smileys/Angry.gif. STUPID COMPUTERS.

All of this discussion has made me ask a question I have been wondering about for a while. I am assuming that the ECM controls the EGR. If this is true, then why would the Edge and other modules not just overwrite this output from the ECM and keep the EGR commanded closed. Or similarly, modules such as TTS or even other programmers would just overwrite this section of the programming and never command it to open. At the same time, they would also be reading the inputs from the EGR system, and could tweak them to be within limits, eliminating setting codes. Or, just adjust these limits altogether with a programmer so that you would never be outside of the acceptable range.


I may be way out in left field with this, but it seems like they found solutions to up the horsepower real quickly, and seem to have done it well. I just imagined that there would be a fix to the EGR by now also, since it is evident that so many people do not like having it. Anyone have any ideas on this? I imagine that it is way more complicated than I am making it sound, but it is just something I have been wondering about.






I am sure they could do this. Liability would be the main reason.

Well...My 03 has a vac assisted actuator with a vac line running into it. I disconnected and capped off both ends and she ran pretty good for about 20 miles. I decided to romp 1-3 and hellow SES light. Took it to the dealer and he cleared the insuficient egr flow. I'll stick with stock and use the isiot light for something major.

Smokeymax, did it run poorly after the idiot light came on? If not and you liked the performance increase several others have elected to live with or cover up the light. Good luck. JJ http://www.dieselplace.com/forum/smileys/Rock On.gif

This may seem like a stupid question but I'll ask anyway. I disconnected my egr last night and drove it around 80 miles or so. I didn't notice any dramatic change in milage in my instant mpg according to my dic. But I will say that the turbo does seem to spool up a lot faster and the bottom end is better. It was quite windy yesterday so I'll have to try it on a little bit calmer day. Anyway on to the question. The lly's have an elevated Idle that aids in cold weather warming. How is this accomplished? To my knowledge there is no wastegate so it doesn't do it like the 7.3 furds. So do you need the egr for this to work.

THANKS MAX POWER !!! You just may have saved me thousands of dollars $$ from buying a different truck. Unplugged the EGR valve on my LLY and have driven it all around with town/highway driving . Have had NO lights, troubles , or buzzers ! The only trouble im gonna have is I may need some tires sooner than i thought . LOL Baahhahhaahhahttp://www.dieselplace.com/forum/smileys/Clap.gif Like everyone else is saying ;feels more like my old LB7, quicker spool up , more power, mo-better !!


Looks like mileage may go up to just by looking at the instant economy on the DIC but who knows yet as i cant keep my foot out of it. ha

In JJ post above it says "EGR flow is disabled if any EGR codes are set" Would that mean on cali trucks you could unplug set the code then plug back in to turn off SES light and EGR would still be disabled due to the set code?

I think that those without federal emissions will be SOL. I think the light is being set due to the low EGR flow determined by the MAF sensor and not just because the motor is unplugged.

so i got a north east truck if i go unplug it and i set a code and the light comes on can i just plug it back in and th elight goes away?


i dont like lights. and if the light doesnt go away do i have to go to a dealer or can i just reset the code my self?

The light should go away after a few starts. There will still be codes there but no light.


This is also likely why some are seeing codes after removing their cat and others aren't.

i just disconected it did about 5 miles and it runs fine revs a little quicker and takes off a little better. i also pluged it back in and re did the 5 miles and their is a deffernce.


their is no more smoke and it does feel quicker.

correction my chjeck engine light is on. will go off? if so in how long? i dont like lights on.

I really didn't notice much difference. If there was an extra MPG I would be suprised. One thing to remember is the egr cooling can has the cab heater flow going through it...might be a cold winter and...the return exhaust will warm the engine faster.

I think this EGR mod only helps the LLY guys. I noticed a big difference right away. If you have an '03, I don't think it has the same programing/symptoms as the LLY.

Smokey Max, I just filled up my second tank. Combonation city/hwy driving and I am up 2.4 mpg better then my best tank before.

I would be surprised if you DIDN'T see at least a 1mpg improvement.


We did fine with our LB7's with no EGR. No cold winters yet.

Max Power,


You know, I was just going through the upfitters guide (electrical) and noticed they have wiring for LLY. Check out page 195 of 308. We'll see how it compares to Helm's tomorrow.


Dennis

Max Power,


I'm sure our temps here in Georgia at 90+ make a difference. I get 18-19 when its 55 degrees.


http://www.weathercentral.com/weather/canada/cities/mb_winnipeg.html

Oh, yeah, here's the link. You just have to 'save as' the link for 2003 and beyond electrical guide.


http://www.gmupfitter.com/publicat/ld_2004.htm


Dennis

Max Power,


I'm sure our temps here in Georgia at 90+ make a difference. I get 18-19 when its 55 degrees.


http://www.weathercentral.com/weather/canada/cities/mb_winnipeg.html





We get over 90 here in the summer as well. It's cool today but at the end of the week they are calling for above 90 temps.


Irregardless of temperature, I know there is an improvement.


****Edit, well they were. Now they're calling for mid 80's http://www.dieselplace.com/forum/smileys/Disapprove.gifEdited by: Max Power

All of this discussion has made me ask a question I have been wondering about for a while. I am assuming that the ECM controls the EGR. If this is true, then why would the Edge and other modules not just overwrite this output from the ECM and keep the EGR commanded closed. Or similarly, modules such as TTS or even other programmers would just overwrite this section of the programming and never command it to open. At the same time, they would also be reading the inputs from the EGR system, and could tweak them to be within limits, eliminating setting codes. Or, just adjust these limits altogether with a programmer so that you would never be outside of the acceptable range.


I may be way out in left field with this, but it seems like they found solutions to up the horsepower real quickly, and seem to have done it well. I just imagined that there would be a fix to the EGR by now also, since it is evident that so many people do not like having it. Anyone have any ideas on this? I imagine that it is way more complicated than I am making it sound, but it is just something I have been wondering about.








Simple, the EPA would sue the hell out of anyone disabling smog devices. EGR is an inert gas (can't burn again). Thus, since it doesn't burn, it can't create heat which causes NOX (oxidesof nitrogen-basically a chemical change when air is super heated, and nitrogen atoms split off and become NO (nitrogen and oxygen). This is the stuff that turns air yellow. When you inject exhaust back into the mixture, you are basically displacing oxygen that would create heat. What causes NOX? super high compression ratios, advanced timing and very lean mixtures.

I got to thinking about this before I did it...

An EGR system is for recirculating exhaust gases to reduce oxygen in the combustion process so NOx (nitorgen oxide) is not created. Is the EGR only on at idle or under acceleration through the gears, too?Edited by: hamsalad

hamsalad, in my first post there is a link to another post. In that post it defines the conditions in which the EGR will be open.

http://www.dieselplace.com/forum/smileys/Confused.gif I went to pull the EGR switch tonight and couldn't find a five wire connection by the oil dipstick and behind the intake. Yes, its official, I'm a moron! I almost disconnected an electrical connection that was similar to 2 others by the injectors. I'm dangerous I tell ya! Does anyone have a good picture, other than the diagram posted earlier, that shows exactly where this connection is at. I want to pull it in the morning before I drive to work. Thanks! http://www.dieselplace.com/forum/smileys/Embarrased.gif

below the intake and to the driver side of the dip stick.

Max Power,


I'm sure our temps here in Georgia at 90+ make a difference. I get 18-19 when its 55 degrees.


http://www.weathercentral.com/weather/canada/cities/mb_winnipeg.html





We get over 90 here in the summer as well. It's cool today but at the end of the week they are calling for above 90 temps.


Irregardless of temperature, I know there is an improvement.


****Edit, well they were. Now they're calling for mid 80's http://www.dieselplace.com/forum/smileys/Disapprove.gif





Send some of that 90 degree stuff to the states! We are having highs in the low 60's here in Minneapolis!!


BTW, disconnected the EGR a few days ago, so far so good, but the wife has been driving and she cannot tell the difference. However, it would most likely take an added 100hp and 10mpg for her to notice!

We are having awful weather this year. Probably similar to you guys.

Max Power,


You know, I was just going through the upfitters guide (electrical) and noticed they have wiring for LLY. Check out page 195 of 308. We'll see how it compares to Helm's tomorrow.


Dennis

195 of 308? where did you get that thing? what I got off the web only went to page 80.

Jim

http://www.dieselplace.com/forum/smileys/Confused.gif I went to pull the EGR switch tonight and couldn't find a five wire connection by the oil dipstick and behind the intake. Yes, its official, I'm a moron! I almost disconnected an electrical connection that was similar to 2 others by the injectors. I'm dangerous I tell ya! Does anyone have a good picture, other than the diagram posted earlier, that shows exactly where this connection is at. I want to pull it in the morning before I drive to work. Thanks! http://www.dieselplace.com/forum/smileys/Embarrased.gif





ya i had a hard time to. just get uo 5 min early take the tube that goes from the air box to the engine. its only 2 screw clamps. as soon as u move that tube its right their. it got all differnt collor wires. as soon as u move that tube its right their. i know it took me a while also to find it. it is also easier to work with that way. its hard to pull off.

I was able to find the EGR and disconnect it, but my SES came on and won't go off. I re-connected it and I am not sure what to do next. Anybody have some suggestions?

It will go off on it's on just give it a couple days of starts and stops. You are in Cali, it was discussed above that the light would come on. Either that or go to a autozone or something like that where the read and clear the codes for free.

Max Power,



You know, I was just going through the upfitters guide (electrical) and noticed they have wiring for LLY. Check out page 195 of 308. We'll see how it compares to Helm's tomorrow.



Dennis




195 of 308? where did you get that thing? what I got off the web only went to page 80.

Jim


Jim,


Try this link. It should automatically start Adobe and download the pub. It's a shade under 4 MB.


http://www.gmupfitter.com/publicat/2004_BB/2003_Beyond_LD_Electric_CK.pdf


Good Luck,
Dennis

Easy way to find the 5 wire plug in on the EGR is stand on the passenger side of truck, find dipstick, about 4"s from dipstick just under the plastic 4" rippled air intake tube. I would think this only works for the LLY guys. Put about a 150 stop and go shut off and start miles on it tonight and REALLY like the quicker response . VERY noticeable to me. I too was looking ontop of the motor and to the back by turbo but then Max Power told me where it was so dont feel bad.http://www.dieselplace.com/forum/smileys/Embarrased.gif

Very cool!


I did notice a better off the line feel, less turbo lag and what seems to be better fuel mileage, I reset my mileage and it has gone up by more than 3 mpg.


Thanks for the advice!!!

Every morning when I back out of my garage down my driveway and onto the road I can hear the difference. The turbo spools up backing out of my garage where it never did before. I can get up to ~6 lbs of boost backing out of my driveway. With it plugged in I get 0. Kinda cool to hear that turbo when you're not expecting it.http://www.dieselplace.com/forum/smileys/Cool.gif

Yep me too. I could hardly spin out on rocks ( upon initial takeoff) now it rips up the gravel when im not even trying in the driveway. I did a 4 wd launch today (pavement of coarse) with it unplugged and it ripped the shiat out of the tires where as with it plugged in you had to REALLY REALLY pwr brake it up to get boost and to squeak them.

Dennis,

Thanks for the linkhttp://www.dieselplace.com/forum/smileys/Big Smile.gif http://www.dieselplace.com/forum/smileys/Big Smile.gif http://www.dieselplace.com/forum/smileys/Big Smile.gif

Jim

This mod sounds so cool and easy, too. I don't mean to be a party pooper at all, but what exactly does this do to the combustion process? So, exhaust gases are not being recirculated back into the manifold...so that means more oxygen, right? Any chance for carbon or soot buildup? Would more oxygen mean higher pressure and temps during combustion?
Sorry, but I am just trying to wrap my tired brain around this tonight http://www.dieselplace.com/forum/smileys/Big Smile.gif

Would disconnecting the cat help even more?

You are actually decreasing the carbon/soot build up in the intake side. Basically the engine can now burn clean oxygen which will increase power, increase fuel mileage and should also decrease exhaust gas temperatures. Also because the EGR cooling tube uses engine coolant to cool the Exhaust gas being recirculated back into the engine it should also allow the engine to run cooler.


From what I understand of this there are many benefits. Some go much deaper then meets the eye. But there is one downfall and that is higher emissions.


Bottom line, if GM was not forced into meeting higher emission standards the EGR would not be there. Why? Because of all the reasons listed above.

6 lbs of boost backing out of my driveway! How fast you going Max? Later! Frank

Would disconnecting the cat help even more?


I don't think you will see much of a difference by disconnecting the Cat at stock power levels. IMO the only way that the cat affects performance and economy is the added back pressure. At stock levels that is not likely an issue. One of the biggest advantages you will see is that the turbo will likely spool up quicker because of the reductions of back pressure. This won't really give you any extra power or fuel economy it will just make it snappier off the line.

6 lbs of boost backing out of my driveway! How fast you going Max? Later! Frank Not very fast at all. It makes that much difference!

With my 34" H2 tires and wheels, I can use more low end. I am waiting for Banks to make the new LLY kit available for sale.

Man, this thread is going too fast, can't keep up. I finally disconnected the EGR last night and drove it about 20miles stopping and starting several times (honey do list). I really did not expect to feel any difference, but like all you other guys, there is a noticable difference--it does run stronger!! No lights, tonight I am taping the ends of the connection to keep the dirt and crap out and do not plan on reconnecting unless it goes in for warrenty work. Cool, easy mod that works, thanks maxpower! Also, made it to the dealer and showed them my bubbled side molding, service lady was perplexed, then a dude came out and said yep that is a problem with that color, put him on the list--I guess the molding is on back order--but they will call me when it comes in. Funny thing is we did these same mods to our cars back in the seventies when EGR and cats came out for gassers, it worked then and it works now, which really surprises me with all the computor controlled crap now days. Wonder what this would do to a modern gas motor? prob. set codes like crazy. Juice should be here tomarrow or next day--will post results. Now to get ride of the kitty and that huge muffler!

Yeah, but Max Power has two black streaks that start just inside the garage door and go all the way out to the street!http://www.dieselplace.com/forum/smileys/Big Smile.gif


Dennis

I've done the egr thing and it seems to work well. But what about winter time. The lly's are equipped with elevated idle. Does it have to have an operable egr for this to work properly. After all it does recirculate exhaust gasses which is heat which in turn would heat up the engine faster, correct. So is this feature still going to work?

I'm certainly getting better fuel mileage now with the EGR disconnected,


But how will this decrease exhaust gas temps?


Isn't the EGR system designed to decrease the combustion temps and therefore that should decrease the exhaust gas temps? I would have thought that disconnecting the EGR would increase EGT's slightly.


I made a run to the city yesterday, mostly all highway at about 110 to 120 km's per hour, faster than normal and still didn't use as much fuel as I normally did running at 90 to 100 on previous trips


Thanks Max Power!


Rob

Yeah I too would like to know more on the relationship between EGR and elevated idle.

Right from John Kennedy's website tech tips:







<DIV align=center>
<H3>Manual High Idle System Description</H3></DIV>


The diesel engine has a high idle system to improve the warm-up time of the engine in cold weather conditions. This system allows the engine control module (ECM) to increase the idle speed above the normal calibrated value.

The ECM increases the idle speed using the following adjustments:


<UL>
<LI>The fuel injection timing is changed.

<LI>The fuel injection quantity is changed.

<LI>The turbocharger vane position is commanded closed. the vane position will be farther closed than any other normal operating condition.
</LI>[/list]


The instrument panel will indicate the high idle system is active one of two ways:


<UL>
<LI>The Driver Information Center (DIC) will indicate an active high idle system on Light Duty Trucks.

<LI>An indicator lamp will flash on medium duty trucks.
</LI>[/list]

sweet!

The high idle is computer controled. It should have nothing to do with the EGR at all. We had high idle on LB7's that don't even have EGRs.


My theory on cooler exhaust gas temperatures is just that, a theory. I assume that becuase the engine is not having to burn, unburnable exhaust gas, and now can burn clean oxygen it shouldn't require as much fuel (therefor better fuel mileage) to burn properly. Therefor a cleaner burn and lower exhaust gas temperatures. We know that the more air we can pump into the combustion chamber, the cooler our exhaust gas temperatures will be. Maybe I am way off on this one.


As far as I know the EGR isn't designed to decrease combustion temps rather just recycle exhaust gasses to reduce emmissions at any cost.

http://www.dieselplace.com/forum/smileys/Clap.gifYeah Baby Yeah! Disconnected the EGR this morning (thanks MaxPower) for the intel. For those of you mechanically challenged like me from the front left side of the truck look under the plastic air intake tube and to the right of the dipstick on top of the engine and you will see the EGR connection with the five wires. Take a screwdriver and push it off (surprisingly easy to come off). Turbo spool up does seem better, but I didn't see any black smoke when I pushed it getting on the interestate. I'll advise on MPG after the weekend.
As for the EGR post above, this if from the LLY engine page: "Engine coolant is used to cool EGR flow. Exhaust gases are scavenged from the right side turbo exhaust inlet pipe, cooled by coolant flow, then injected into the intake manifold on the engine. The combination of exhaust restriction produced by the turbo, catalytic converter and exhaust system raise the exhaust backpressure to a level above intake manifold pressure. For now at least, EGR flow is not being routed through the intercooler."
OK, my take on this and no laughing please!http://www.dieselplace.com/forum/smileys/Evil Smile.gif Since GM was going for the 2007 EPA standard with the LLY, in order to route unburnt gases back into the engine for recombustion without creating an overheating affect they have to cool these gases first, otherwise they would drive temperatures even higher. http://www.dieselplace.com/forum/smileys/Geek.gif My parunts wuz wrung, all dat stuf I drankded in my yungar yars didn damage ma brayne(lol).
I do notice the truck seems to have less resistance when coasting to a stop. This might be attributable to the lack of backpressure noted above. One concern is when I'm towing heavy I like the way the D/A slows the truck on its own. I have to think part of the effectiveness is with backpressure. We'll see. http://www.dieselplace.com/forum/smileys/HiHi.gif

Anyone,


Do any of you have an aftermarket EGT gauge to tell if the temps are higher after unplugging the egr?


Scott

Anyone,


Do any of you have an aftermarket EGT gauge to tell if the temps are higher after unplugging the egr?


Scott





too early to tell, my egr's have been pretty low since i removed the cat - but i will be towing this weekend and will get a better idea of the egt's when towing, which is what i want to know, although IMO it doesnt really matter if it doesnt lower it, just curious. Gas mileage is better so far after 50 miles

I do, but its hard to tell with any degree of accuracy due to so many variables. One thing is for sure, it doesn't increase EGT's any measuarable amount. Not a concern for me at all.

OK, my take on this and no laughing please!http://www.dieselplace.com/forum/smileys/Evil Smile.gif Since GM was going for the 2007 EPA standard with the LLY, in order to route unburnt gases back into the engine for recombustion without creating an overheating affect they have to cool these gases first, otherwise they would drive temperatures even higher. http://www.dieselplace.com/forum/smileys/Geek.gif My parunts wuz wrung, all dat stuf I drankded in my yungar yars didn damage ma brayne(lol). I realized I didn't finish my thought process above (duh). If 100% of the hot exhaust gases are being pushed out of the engine without restriction (backpressure) versus whatever % is being rerouted, cooled and burned again, one could reason that the EGT's should be lower. Did that make sense? Anyone running juice/attitude with EGT monitor should be able to answer this question. Well? JJ

Tbone, how much did your EGT's go down when you removed the CAT? I tow heavy and EGT's are a major concern. I've read several posts where they state removing the CAT doesn't lower EGT's, and the vehicle won't operate as well since it is calibrated for the CAT.


Also, did you change your exhaust? The stock exhaust is huge on these trucks, I'm having a hard time believing 4" versus 3.5" will make a huge difference. I'm spent quite a bit of money in the 8 weeks I've had the truck, Mama is losing her patience and wants a new washer for the RV. Wazzup? JJ http://dieselplace.com/forum/smileys/Ermm.gif

JJ - i installed a Magnaflow Turbo Back - 4" all the way through ( 5" tip exhaust tip ), and it definitely lowers the egt's - i would say by 60-100 depending on conditions - it flows better, truck runs better, quicker spool up, better response - so i would say that whoever told you opposite didnt have correct info, as mine is completely opposite and its definitely better !! It does smell more now though, but oh well, it hammers, especially with TTS Tow Tune and Edge/*** set on 5 http://www.dieselplace.com/forum/smileys/Big Smile.gifEdited by: tbone1227

Question about California trucks. When the egr is disconnected it will set a code and the SES light will come on. Then reconnect and after some cycles the SES light will go off. Question is will the egr be working normal again? I think read in a previous post the ECM will disable the EGR due to the code being set.

Well if thats the case then you are in luck really. You'd be running with the EGR off and no light.

That's my question are we that lucky?

Cooled EGR: EGR flow is controlled by the LLY's brand new E60 ECM and digitally controlled EGR valve, with programming that takes into account the heat load imposed on the engine's cooling system by the hot exhaust gases. EGR flow can occur when IAT (intake air temperature) is above 41.5°F and with an engine temperature between approximately 140°F and 211°F. Terminating EGR flow above 211°F helps to preserve the cooling ability of the engine. The EGR stepper motor and control valve assembly are serviceable, and new OBD II diagnostic procedures allow the technician to monitor/test the operation of the EGR.<font color="red">EGR flow is disabled if any of the EGR related DTC's are set.</font>

The arrow near the top of the image on the left points to the stainless steel cylinder that is part of the cooled EGR system. Engine coolant is used to cool EGR flow. Exhaust gases are scavenged from the right side turbo exhaust inlet pipe, cooled by coolant flow, then injected into the intake manifold on the engine. The combination of exhaust restriction produced by the turbo, catalytic converter and exhaust system raise the exhaust backpressure to a level above intake manifold pressure. For now at least, EGR flow is not being routed through the intercooler.

The EGR will more than likely be working again. After several key cycles the computer will have figured out that it is working in spec's again and will just store the code to let a technician know that at one point in time there was an issue with the EGR.

http://www.dieselplace.com/forum/smileys/Geek.gif With the EGR operational the LLY is pulling a percentage of the already "superheated" exhaust, cooling it slightly, then reintroducing it with fresh air to be combusted again and again and again. Without the EGR we are only pulling cooler "fresh air" through the intake for combustion and 100% discharge with no backpressure. Doesn't that sound like a formula for lower EGT's and better MPG's? I drove my truck down the interstate during lunch and the turbo is much more responsive as is low end throttle response. MPG's to post over the weekend. JJ http://www.dieselplace.com/forum/smileys/Rock On.gif

I would think it will work again. I took my stepper motor off and and plugged it into the harness and it was cycling. So my truck would have a code set and it was still activating the stepper motor.

http://www.dieselplace.com/forum/smileys/Geek.gif With the EGR operational the LLY is pulling a percentage of the already "superheated" exhaust, cooling it slightly, then reintroducing it with fresh air to be combusted again and again and again. Without the EGR we are only pulling cooler "fresh air" through the intake for combustion and 100% discharge with no backpressure. Doesn't that sound like a formula for lower EGT's and better MPG's? I drove my truck down the interstate during lunch and the turbo is much more responsive as is low end throttle response. MPG's to post over the weekend. JJ http://www.dieselplace.com/forum/smileys/Rock On.gif



Your mileage will probably be worse because you keep checking turbo response improvements. http://www.dieselplace.com/forum/smileys/HiHi.gif

I think JJ is right. The only issue I wonder about the EGR being off is at that oxygen levels would be higher. Would that elevate the temperatures during combustion negating the benefit of the recirculated/cooled exhaust being shut off?

You know this discussion about cooled EGR also makes me think the load on the cooling system won't be near as great as it was with the EGR, if engine coolant is what is reducing exhaust temperature prior to intake, then that heat load (and probably a very big one) will be gone, therefore less load on the coolant and (probably) lower underhood temperature as well since you won't have another hot pipe coming right into the middle of the engine bay. I wonder if that will help solve some of the heat issues people are having (poor A/C, transmission cooling)? Any thoughts?


Dennis

I did not think about what baimpala said. Food for thought...I bet he is right.

http://www.dieselplace.com/forum/smileys/Cry.gif Somebody out there thinks JJ could be right! If you guys only knew how big a d_psh_t (fill in blanks) is out here on the other end of these posts. The way I see it, if I can pose enough questions to get you smart guys out there to spill your gutshttp://www.dieselplace.com/forum/smileys/Throw Up.giffor me to go to school on I'll be happy.


Just how thick is JJ you might ask. JJ purchased Mobil Delvac 1300 thinking it was the synthetic oil (Delvac 1). Yeah, thought I got a bargain at $5.88 a gallon at Wally World, then found it mighty strange that all the other people on this site were paying $20-22 per gallon. Duh!


I really do appreciate you techie guys allowing me to pick your brains and to "go-to-school" on your experiences with these trucks. http://www.dieselplace.com/forum/smileys/Hug.gif


MaxPower, you are so right on the mpg's. Maybe I better have Mama drive the truck for the mpg check. She gives me such a pathetic look when I hit the pedal and launch "the beast". Mods are comin! JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

You know this discussion about cooled EGR also makes me think the load on the cooling system won't be near as great as it was with the EGR, if engine coolant is what is reducing exhaust temperature prior to intake, then that heat load (and probably a very big one) will be gone, therefore less load on the coolant and (probably) lower underhood temperature as well since you won't have another hot pipe coming right into the middle of the engine bay. I wonder if that will help solve some of the heat issues people are having (poor A/C, transmission cooling)? Any thoughts?


Dennis






I think I said that earlier, it just wasn't put as eloquently. http://www.dieselplace.com/forum/smileys/Big Smile.gif



And I agree. It has to help some.Edited by: Max Power

If it is that easy to cool my truck, I will do it the next time I tow. I just wish we could have some sort of formal acknolegement that this will not hurt anything furter down the road. The only reassurance that I have is the fact that this thing shuts when the engine temp goes above 211 anyway. That is normally when everything is going full blast. If the program shuts it down at full blast, then running normal with it shut should have no bad effects besides emmisions. If it is true that federally, they are meeting some 2007 guideline, then why would it be illegal for them to admit that they do not have the cooling capacity for this, reprogram it and next year (or before 2007) come up with a cooling system that can handle it?


Has anyone thought of any other ways to disable? Fuse? Relay? Hate to have wires danglin, what about putting something in the connector to insulate, and then back together?

Great minds think alike, apparantly one of them just doesn't listen. Ha ha. Well, good news, the Helms manual just arrived from the Big Brown Truck (a diesel). Good Gawd, this thing is big. The one for my Impala was two volumes about 2" thick each. This thing is FIVE volumes, each about 2-1/2" thick. Holy crap this thing is awesome! Give me some time to browse through it and then I'll figure out the EGR thing.


Dennis

A quick look at the Engine Control Schematics shows the gmupfitters guide is dead on with their circuit.


exford, no the signals and controls all come directly from the ECM. I don't think anyone would give you a 'formal' acknowledgement that this will not hurt anything. Just do it, if it causes problems, plug it back in and take it to the dealer. Are you already out of warranty?


Dennis


BTW, I did mine this morning. . . Like buttah.Edited by: baimpala

No, not out of warranty, just don't want to go back to dealer. It is nice to have a warranty when you are on the side of the road, but you are still on the side of the road. I usually have my wife and 1 year old with me and my wife can really scream.

I am in ny and have had a code set for a long time because I installed a 4" system 20,000 miles ago. the code is insufficent egr flow. I am assuming this is because of the MAF sensor. Were is this sensor, and how can I trick this sensor into thinking it is getting enough egr flow. I am sick of having this light on, and I want to know if something else goes wrong that the light will come on. ps I also unplugged my stepper motor today.

I'm with you on that one. They make earplugs, you know, usually about 31 dB gain.http://www.dieselplace.com/forum/smileys/Big Smile.gif I have a 2-1/2 and a 10-month old. I doubt seriously if you would do any long term damage (the LB7's are going strong without one, which was my reasoning behind going ahead with it).


Dennis

Here are some words out of the Book of Helms for DTC P0401:


DTC P0401 EGR Flow Insufficient


Conditions for Setting the DTC: The MAF difference monitored by the ECM during the EGR flow test indicates an insufficient amount of EGR flow.


Actions Taken When the DTC Sets-California:


- The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a fialure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.


Actions Taken When the DTC Sets-Federal


- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
- The driver information center, if equipped, may display a message.


Conditions for Clearing the MIL/DTC


- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and DTC with a scan tool.


Same type of information for:
P0403 EGR Solenoid Control Circuit
P0404 EGR Open Position Performance
P0405 EGR Position Sensor Circuit Low Voltage
P0406 EGR Position Sensor Circuit High Voltage

It would be interseting to know if Diesel Tech (TTS) has 3 different programs with his TTS tune. California, Federal etc.


If all of his tunes are Federal, those of you with a check engine light could just get a TTS tow tune and no longer have check engine light. http://www.dieselplace.com/forum/smileys/Big Smile.gif

so basicly all i got to do is turn my key on and off 3 times and it clears the code?

MP


I'm assuming that since I have no check lights disabling the EGR valve that I'm also safe to remove the cat as well without tripping a light with the rig I have, Do you think thats a fair assumption?


I need that TTS tow tune,


Rob

yamahagrizzly,


I thought you had to actually start the truck for that to work and it would only clear the current DTC. To clear one from history it would take 40 warm-up cycles (whatever that means, I suppose heat up to normal temp before shut down).


04ROB,


If you have Federal Emissions, you are most likely safe to remove the Catalytic Converter without fear of getting the light.


DennisEdited by: baimpala

so basicly all i got to do is turn my key on and off 3 times and it clears the code?


Probably about 10 or so normal start and stops and it will go off. Just forget about it for a day or two.

MP


I'm assuming that since I have no check lights disabling the EGR valve that I'm also safe to remove the cat as well without tripping a light with the rig I have, Do you think thats a fair assumption?


I need that TTS tow tune,


Rob











I would assume that as well. I don't know for sure however. Try it and let us know. http://www.dieselplace.com/forum/smileys/Big Smile.gif

Thanks MP and Dennis,


Think I'll look into that change.





Rob

I tried unhooking my EGR and my empty mileage went up, but towing went down. Any thoughts??

Likely just conditions. There is no reason it should go down as a result of the disconnecting the EGR.

I tried top read all the post but just couldn't get it done. i disconnected mine this evening and tomorrow while I am running around I am going to put the Tech II on and see if anything is going on.

Greg

You will get codes Greg. There isn't any doubt about that. But if it means better mileage and longer engine life, I'll live with a few codes. http://www.dieselplace.com/forum/smileys/Big Smile.gif

No doubt you have to have codes but I want to see what they are.

We have been doing funny things on VW TDI egr's for sometime. I can tell one thing for sure and that is the intake WILL get clogged over time if you don't do something with the egr. But this is a different style egr and it might not plug as easy.

Greg

After putting 285's on, my truck felt kind of sluggish. Now it has more get up and go. Thanks for sharing MP!

I unplugged my EGR this evening and drove it around. I got an engine light on the second time I started it up and the light has stayed on over a few startup and stops.

The turbo spools quicker and the throttle seems to respond a little snappier, too. Overall, I can feel the change quite well. No change in any engine noise.

I wish that light would go out!

Unplugged mine on the 8th. Definate turbo spool improvement. Easier to break the tires free when doing powerbraking starts. SES light came on when I started the truck the 2nd time after disconnecting the EGR. I haven't been light on the peddle so no noticeable improvement in fuel mileage yet. I should see what it did for fuel mileage in the next week or two.

OK so ive been following this post and maybe I missed somthing.......when do we unplug the EGR?


In the am when the engine is cold and hasnt been started overnight or let it warm up to norm op temp, shut it off, then unplug it? Thanks...

Thanks for the tip M.P. disconnected mine yesterday and a noticable difference http://www.dieselplace.com/forum/smileys/Big Smile.gif 200 miles &amp; no s.e.s light yet http://www.dieselplace.com/forum/smileys/Big Smile.gif Edited by: DMAX-MIKE

Tech says,


When the engine is cold, start it, (I'd let it run for about 15 seconds)then shut it off, unplug and you now have completed the............


"Max Mod"


Saves fuel, spools turbos quicker, runs cleaner, lasts longer, grows hair,


(naw, doesn't grow hair, I was just kiddin ya) http://www.dieselplace.com/forum/smileys/Embarrased.gif





Rob

I just unplugged mine after truck had been sitting for about 5 or 6 hours and have NO problems at all yet !

thanks guys...............

Unplugged mine about 9:00 this morning, took about a 15 mi. trip around town and so on, no SES light..


A tad more smoke at IDLE to Pre-turbo spool up, no differance at speed, IMO!!!!


BTW: I run 4" MBRP T-409SS exhuast and NO Cat. (for about 2000mi. now)


BIGhttp://www.dieselplace.com/forum/smileys/Big Smile.gif

I unplugged mine last night and could feel the turbo spool up quicker and I noticed the nocking sound the engine used to have is gone. I also noticed that the grade braking does not feel as pronounced as it used to . I will be towing my 7000lb trailer this weekend so I will see if there are any differnces.





I do have a question, what will happen when I go for my emmisions test next year, I live in Utah and it is required. Just curious.

I notice that some of you report a little bit of smoke just off of idle. My truck has never smoked and now, after the mod it still does not smoke even if I throttle it hard. I run Chevron diesel fuel since the truck was new. Not that I want it to smoke, but it was something I noticed.

I unplugged mine last night and could feel the turbo spool up quicker and I noticed the nocking sound the engine used to have is gone. I also noticed that the grade braking does not feel as pronounced as it used to . I will be towing my 7000lb trailer this weekend so I will see if there are any differnces.





I do have a question, what will happen when I go for my emmisions test next year, I live in Utah and it is required. Just curious.





Plug the EGR back in. Have the codes erased to be on the safe side as well. As soon as the EGR is plugged back in, it should meet emmssions again.

Thanks for the reply, would I need to go to the dealer to get the code erased?

[QUOTE=falk1rk] I also noticed that the grade braking does not feel as pronounced as it used to . I will be towing my 7000lb trailer this weekend so I will see if there are any differnces.


I noticed the same thing when I exited off the interstate the truck seemed to coast with very little engine resistance in comparison to having the EGR operational. I wonder if the backpressure created by the EGR had an affect similar to an exhaust brake? I won't be towing this weekend since we have "Bonnie" and "Charley" heading our way with lotsa rain and high winds. Let us know how it goes falk1rk. JJhttp://www.dieselplace.com/forum/smileys/Approve.gif

Thanks for the reply, would I need to go to the dealer to get the code erased?


Anyone with a code reader can do it. I think you can go to a place like Autozone and have them read the code and clear it for free.

Thanks for the reply, would I need to go to the dealer to get the code erased?


get yourself a code reader/eraser from an autozone, they work good, you can see exactly what code it is and what it means and erase if choosing so.


- more observations on my part....... hmmm, i hand thought about the towing yet but will be towing this weekend and will check out the grade braking as well... my truck hardly smokes either, even with the TTS and Edge setup, but i dont have a cat either so that might be part of it, not sure... I have noticed that it seems that my tranny temps have been lower ?? 2 days in a row now !!

Mine smokes some when i mash it at idle . I think it seems more responsive when cruising at speed and just giving it a nudge of throttle too . Prolly doesnt help top end power but i think off idle and when giving it some gas it helps. Im still reporting a http://www.dieselplace.com/forum/smileys/Thumbs Up.gif !

get yourself a code reader/eraser from an autozone, they work good, you can see exactly what code it is and what it means and erase if choosing so.


On that note, does anyone have specifics regarding code readers/eraser's that work on a 2004 LLY? Models/makes, and where you got it? What kind of "port" does our truck have?


I'm interested in one of these, if they're not too expensive. (like less than $150).

Just got done putting the Tech II on the LLY. It has only one code the P0410 egr insufficent flow.

Greg

the code readers will work for any vehicle from 1996 and up I believe that have the ODB interface which we have - I paid $149 for mine and I have an LLY.


The codes that I keep getting are: 0401,0405,0404, and 14_ _?? not sure on the last one now, ill check again - but they are all EGR / Emissions Control / Flow - as I have no cat, and now disconnected EGR

Just got done putting the Tech II on the LLY. It has only one code the P0410 egr insufficent flow.

Greg

Thanks Greg!

Greg,


Great info. It seems like Max Power's suspicions were dead on the money. Those with Federal emissions are pretty much set. Got the Juice/Attitude today, this is starting to get fun.


Dennis

Anybody running guages?.....What kind of boost psi + or -?.....How about egt + or -?

Boost is the same because its only going to give it what it asks for. What you will do is spin the wheel a little slower because it won't have to work as hard.

EGT looks the same but I will give it a couple more days.

Greg

Boost and EGT will remain the same. You might see a slight increase in boost but give it alittle time running and it will go right back to where is was to start with. If it doesn't you will get a CEL for boost control. These are closed loop systems and they adjust in to preset values. If outside of the adjustment range it sets a code. EGR works the same. So what most of you feel is the quicker spool up of the turbo and possible better mileage but I'm not so sure that (mpg) will last after the ECM adjust itself in.

Boost and EGT will remain the same. You might see a slight increase in boost but give it alittle time running and it will go right back to where is was to start with. If it doesn't you will get a CEL for boost control. These are closed loop systems and they adjust in to preset values. If outside of the adjustment range it sets a code. EGR works the same. So what most of you feel is the quicker spool up of the turbo and possible better mileage but I'm not so sure that (mpg) will last after the ECM adjust itself in.


Sure, just go ahead and rain on our parade http://www.dieselplace.com/forum/smileys/Big Smile.gif

So, I picked up a scanner at autozone for 149.99 No codes yet, and mine has been running for about 125 miles with it unplugged.


So far, so good!

No egr . No codes, no problems, ordered truck from a Florida dealer. This state is very leniant on emisions, you could run exhaust out the hood if you wanted... Better mpg and much better low-end response, just like my old LB7.http://www.dieselplace.com/forum/smileys/Clap.gif

Even if the EGT's, boost, turbo spool up and all the other great things we anticipated don't pan out, we're still not running soot back through the intake over and over again.


Still waiting to hear the MPG verdict. Wazzup? JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

UNHOOKED EGR DROVE 15 MILES HOOKED BACK UP TOOK TO DEALER FOR INJECTOR PROBLEM HAD P0404 P0405 AND ONE OTHER CODE AND THEY EVEN KNEW HOW MANY MILES AGO I HAD UNPLUGGED.. THEY WERENT CONCERENED AT ALL I DIDNT SEE ANY IMPROVEMENTS IN PERFORMANCE BUT I LIKE THE IDEA

UNHOOKED EGR DROVE 15 MILES HOOKED BACK UP TOOK TO DEALER FOR INJECTOR PROBLEM HAD P0404 P0405 AND ONE OTHER CODE AND THEY EVEN KNEW HOW MANY MILES AGO I HAD UNPLUGGED.. THEY WERENT CONCERENED AT ALL I DIDNT SEE ANY IMPROVEMENTS IN PERFORMANCE BUT I LIKE THE IDEA


Question for the diesel techs.

How much information can the dealers service centers get about what we do to our vehicles behind their backs (at least that's what we like to think)? If they were able to tell when mil5t disconnected his that could become an issue if something does fail regardless of whether it's caused by the EGR not being connected or in it's original state. Also when we erase the codes before going to the dealer (using the autozone method for example) can they still tell when and if it was disconnected?

if you clear the codes yourself, I don't think there's anything they can know about it

Would this be applicable to those who have their SES light activated? It's the procedure I use to clear the light in my Z, and I've used it on other GM products as well.


Mark
Instructions on How to Reset the LS1 ECM
<SMALL>Submitted by: Scott Harroff</SMALL>
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<CENTER>
<TABLE width="75%">
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<TR>
<TD align=middle width="100%">
This is intended to reset that aggravating 'Service Engine Soon' light so many of us seem to see. The light is normally set due to a loose gas cap or a high frequency error on the mass air flow sensor in front of the intake manifold. If the light persists, you may want to have you car checked by a GM dealer. It may be a good idea to remove your K&amp;N air filter, and replace it with the stock filter or equivalent before your visit to the dealer. Dealers, in the past, have been known to blame the MAS error on excessive oil in the K&amp;N leaking onto the MAS. If the fuses aren't removed in this procedure, the codes will be stored in the ECM until the fuses are removed, or the dealer clears them with a scan tool. Rumors have it that stored codes retard timing and spark ignition which will hender the performance of you LS1.
1. Turn key on but don't start car.
2. Pull PCM BAT and PCM IGN fuses in engine compartment.
3. Wait a few minutes.
4. Turn ignition off.
5. Replace fuses.

It will take the car a while to relearn the fuel and timing curves so don't worry about a temporary performance loss.
</TD></TR></T></TABLE></CENTER></DIV>

? on above, will doing that make it so the codes dont keep coming up or is this just a preventitive measure against the stealer ?

preventative

lakingslayer,


The computer writes a bunch of information to the memory any time a fault code is generated. If you clear the fault code, the other stuff goes away with it. It's a database, if you clear a record, it's gone.


Dennis

I should have prefaced that comment with, "I'm not a tech but IMO."


Dennis

I don't know about the Duramax - but my Tahoe you need to wait for 24hrs and drive about 30 miles for the codes to completly clear - I had to do this for State Insp. - failed the emisions 2 hours after clearing code - passed the next day. If the state computers can dig out the old codes, I would have to assume that GM can also. Had a mechanic buddy tell me this also - but then again he could of been blowing smoke up my .............

Unhooked mine yesterday! http://www.dieselplace.com/forum/smileys/Approve.gif Better throttle response and MPG has incresed http://www.dieselplace.com/forum/smileys/Clap.gif

My real concern is what the long term effects might be.

I guess we'll have to wait and see.

Long term effect will be nothing but good. There is nothing good about running exhaust gasses back through your intake.

ok, i disconnected both my egr and my dad's. it seems to help on fuel and both are not smokeing now and they were before. could the egr be making the llys smoke????????

Would this be applicable to those who have their SES light activated? It's the procedure I use to clear the light in my Z, and I've used it on other GM products as well.


Mark
Instructions on How to Reset the LS1 ECM
<SMALL>Submitted by: Scott Harroff</SMALL>
<DIV align=center>
<CENTER>
<TABLE width="75%"><T>
<T>
<TR>
<TD align=middle width="100%">
This is intended to reset that aggravating 'Service Engine Soon' light so many of us seem to see.
1. Turn key on but don't start car.
2. Pull PCM BAT and PCM IGN fuses in engine compartment.
3. Wait a few minutes.
4. Turn ignition off.
5. Replace fuses.

</TD></TR></T></T></TABLE></CENTER></DIV>





IIRC I believe that GM went to non-volatile memory components, so removing power may not erase stored data... http://www.dieselplace.com/forum/smileys/Geek.gif

There are two types of code storage in the ECM. In one case it records everything at the time the code was set includeing odometer reading! The other type codes that donot store all this information may or maynot turn on the CEL. As far as clearing the codes without a scantool by pulling fuses, it only works on current codes provided they are not emmissions related and will not touch the historical codes.

socaldieseltech,
looks like the circuit simply compares actual and ref positions of the egr valve itself via the pos. sensor but NOT the actual flow of air through the egr.
This means there is a "fairly easy" solution without tempering with that egr at all (so no codes should be set). The pipe connecting the exhaust to the intake (with the egr valve in between) just needs to be closed at air intake side with some kind of metal plate.

Neat idea. One question. Has anyone taken this thing off? Looks like it might be bit of a PITA. Helms manuals on the way.

Jim

Blocking the EGR passage is not going to solve the light issue. The ECM looks at the flow based apon a change in the MAF when the EGR is opened Vs. when it's closed. So blocking the EGR will stop the egr but it will also not allow a change in the MAF to occur when the valve is turned on by the ECM. So you will still get the light.

Blocking the EGR passage is not going to solve the light issue. The ECM looks at the flow based apon a change in the MAF when the EGR is opened Vs. when it's closed. So blocking the EGR will stop the egr but it will also not allow a change in the MAF to occur when the valve is turned on by the ECM. So you will still get the light.

correct. Another thread on the egr issue a member suggested disabling the stepper motor after the diagnostics run. This will probably work since the diagnostics only run once per ignition cycle. This approach will probably fix throwing the P04xx codes. The one I haven't spent any time thinking about is the P1404 code. From an earlier post it seems the diagnostics for this run continously. The question is will it throw a P1404 if the stepper motor is diabled.

Waiting on the helms manuals. I could probably go back and re-read the posts on the discriptions also. http://www.dieselplace.com/forum/smileys/Big Smile.gif Thanks for you inputs Diesel Tech.

JimEdited by: jholly

I just disconnected my 2005 GMC. Off the line it is a lot slower than my 2003 was. This seems to help a little. Does anyone else notice the surge of torque when it shifts to second gear? With the EGR disconnected it is more noticable.

nevermind.


Edited by: McRat

Jim,


I'm pretty sure it will. From the book of Helms:


DTC P1404


Circuit Description


The engine control mudule (ECM) uses the exhaust gas recirculation (EGR) position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference cicuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position, is sent from the sensor to the ECM through the EGR position sensor signal circuit. The ECM compares the actual EGR postion with the desired EGR position when the EGR is commanded open or closed. If the ECM detects a difference between the learned closed position and the commanded closed position for a calibrated amount of time, DTC P1404 sets.


Conditions for Running the DTC


- DTCs P0642 and P0643 are not set.
- The ignition is ON for more than 0.5 seconds.
- The ignition voltage is between 11-18 volts.
- The intake air temperature (IAT) is between 0-150.75*C (32-303.35*F)
- The engine coolant temperature (ECT) is between 57-99.75*C (134.6-211.6*F).
- The barometric pressure (BARO) is more than 72 kPa.
- The power take off (PTO) is not engaged.
- The EGR has been commanded to more than 35 percent.
- The current desired EGR position is 0 percent.
- This diagnostic runs continuously while the above conditions are met.


Dennis

It goes on to say that California emissions equipped will still get the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. Federal emissions equipped trucks will NOT get the MIL.


More from Helms:


Conditions for setting the DTC


- The actual EGR position is 0.80 volts, 6 percent, more than the learned closed position when the EGR valve is commanded closed, or the EGR learned minimum position is more than 1.25 volts.
- The above condition is present for more than 5 seconds.


So if you can figure out a simple circuit to substitute the signal in to the sensor circuit for the value it's looking for, you could defeat this DTC.


Dennis

Does anyone else notice the surge of torque when it shifts to second gear?


See this thread:


http://dieselplace.com/forum/forum_posts.asp?TID=13087&amp;PN=1


I don't understand why more forum members don't see and/or write about this. I've seen references to it in several threads but no direct discussion.


On my truck torque is definitely being held back until very late in first gear.

Jim,


I'm pretty sure it will. From the book of Helms:


DTC P1404


Circuit Description


The engine control mudule (ECM) uses the exhaust gas recirculation (EGR) position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5-volt reference cicuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position, is sent from the sensor to the ECM through the EGR position sensor signal circuit. The ECM compares the actual EGR postion with the desired EGR position when the EGR is commanded open or closed. If the ECM detects a difference between the learned closed position and the commanded closed position for a calibrated amount of time, DTC P1404 sets.


Conditions for Running the DTC


- DTCs P0642 and P0643 are not set.
- The ignition is ON for more than 0.5 seconds.
- The ignition voltage is between 11-18 volts.
- The intake air temperature (IAT) is between 0-150.75*C (32-303.35*F)
- The engine coolant temperature (ECT) is between 57-99.75*C (134.6-211.6*F).
- The barometric pressure (BARO) is more than 72 kPa.
- The power take off (PTO) is not engaged.
- The EGR has been commanded to more than 35 percent.
- The current desired EGR position is 0 percent.
- This diagnostic runs continuously while the above conditions are met.


Dennis

Dennis,

If I'm reading it right, the only commanded position it checks for P1404 is the CLOSED position. So it seems to me that if you disable the EGR after it runs the flow tests and it has learned the closed position then it should not set the P1404 code. As for the P0401 code, it opens the EGR valve full, then closes the valve and makes a determination with the MAF between these two positions. I'm guessing that if you let it run the full open and full closed cycle an then disable the stepper your should be code free for at least P1404 and P0401. Need to find out about P0403 and P0404. It could be that P0404 will be the bugger. That is probably the sentence about comparing to the comanded open position to the open position. I think P0405 and P0406 will be a nop.

comments?

Jim

I see what you're saying. I agree, but you would have to disconnect just the EGR motor wires after the start-up DTC runs, and leave the sensor circuit intact. If you did that, any time the commanded position was shut and the DTC 1404 was running, the sensor circuit would return the correct value and no code would be set. That is, if I'm reading the words correctly.


My earlier comments were based on just unplugging the whole dang thang.


Dennis

Smoky and Skyhook - what you both are observing is the fact that the max torque in the vehcile is generated only in 2 -3-4 - 1 & 5, the Alli is protected so it doesn't tear tself apart.

For those of you that are following this and have an '04 LB7 Cal EGR...


Mine has a vacuum pump. The pin is opened using the vacuum supplied from the pump. I pulled the vacuum line from the diaphram on the EGR and plugged it. Second start-up got the light P0401.