Why Is This Towing Again On The Freeway And Truck Lost All Power. Did Not Turn Off Just Had No Throttle Response. Coasted Off The Freeway And Sat For A Sec Then Poof Like New Again No Check Engine, And Yes Brand New Filter Truck Runs Great Just Happens Out Of No Where. What The Fuuuuuc Ccc Kkkkkkkk!!!!

Might get better response if you filled out your signature with the year and mods.:)

Do you have a programmer on it? My Predator makes my truck do that every once in a while when the engine is cold. I've never had it do that after the engine is warm or with the stock tune loaded.

Basically for around 10 seconds you have no increase in RPM's regardless of how much throttle you give it and then it's back to normal correct?

K So I Got My Sig Filled Out Sorry New To All This Please Forgive Me And Thanks For The Response I Do Have Programmer And What Would Make My Programmer Cause This And How To Stop It. I Know Lots Of People Who Have Programmers And Dont Have This Problem

I've had the same issue with a 2001 LB7 with no mods---bone stock and extremely well cared for all it's 70K life now. The throttle postion sensor was changed out a couple years ago because the dealer said it had a short in it. Well the problem still exists and they can't find anything wrong. I get no SES light etc.. I've taken it in a couple more times because it really P's me off, but they can't explain the problem. It seems to do this more when towing, more in hotter weather with higher humidity, and usually only when the truck is up to full operating temp. It will also do it in hot weather without towing, but not as often. I pull over to the side, the truck idles fine, I turn it off for a minute, usually have to restart a couple times, and presto my throttle works fine like nothing ever happened. The really bad part is when it does it in busy stop and go traffic---$HIT!!! The cruise control also works just fine when the throttle goes out so I can drive by cruise until I decide to stop. The cruise operates on a different circuit so hence no issues and the truck runs fantastic. I'll be interested to find out if you can find the problem and resolution for this issue??!!

I would seriously advise installing a lift pump. Seems like as soon as you guy's are really working the engine (demanding more fuel) it's not there.

Wow Walowic1 Hit It On The Nail Exactly Whats Going On Suck You Did Say It Was Just Changing The Throttle Position Sensor That Would Have Made My Day. This Pisses Me Off As Well. So Lift Pump You Say Cuz My Dodge Diesel Did This A Wile Back And It Was The Injection Pump Going Out Got It Fixed Not Cheap And It Was Like New Again. So I Hear Our Duramax Does Not Have A Lift Pump. If So Then Is It Easy To Just Buy And Hook Up, How Much And What Exactly Does This Do To Keep The Fuel Going To The Motor Cause Correct Me If Im Wrong The Injection Pump Seems To Not Be Keeping Up That Would Be The Cp3 Right.

Our CP3's work off vacuum from the fuel tank. They have to suck all the way from the tank through the fuel filter and into the CP3. When running chips or towing and pushing engine to where fuel demand is very high, sometimes the CP3 Bascially starves for fuel.
Installing a lift pump gives you anywhere from 5-15PSI of pressure into the CP3. So whenever the CP3 needs fuel there is always some there.

Thats where i would start if i was you.


On a side note the reason that your dodge injection pump went is because of low fuel lift pump pressure (Very common) on 1st gen 24v engines (VP44) which i'm assuming it is. Don't forget that in all that fuel is lubrication for injectors, injection pumps, etc...

Sounds like injection pump getting weak....CP3. You can help it with a lift pump. There are many available......
Check the injector rates, either with TECH II or dealer. Check fuel pressure. Desired and actual. Check rail pressures.

Cool I Will Start With Buying The Lift Pump That Makes Sence Where Can I Get A Good One At And Are They Hard To Install ?

Many sell them..

PPE
Kennedy Diesel
FASS
Air Dog

Just to name a few...

No they are not hard to install at all. Might need a drill, a couple tools, some wiring and something to cut the fuel lines depending on what pump you are going to install.

Kool Love This Site Thank You Guys Your All The Shit!!! This Forum Is The Best Only Cus Your All About The Dmax. Thanks For The Help I Will Hit You Guys Back And See If The Lift Pump Help Might Take A Couple Of Weeks To Test It Out Once I Get It Done Also Does Having A Lift Pump Add Hp Or Does It Just Help When The Cp3 Want The Fuel?

I really don't think a lift pump will help with this situation. When you're sitting in traffic of just cruising along you aren't demanding a lot of fuel. I don't know what the problem could be but I'm almost 100% sure that it has nothing to do with having a lift pump.

Nick

This has absolutely nothing to do with the lift pump IMO. If it were the lift pump then why does the truck run absolutely perfect with cruise control on running 70 plus mph? Take the cruise off to use the throttle and you might have nothing at the throttle. Put the cruise back on and accelerate with the cruise button and works like nothing is wrong. I can then drive into a rest area coasting to a stop pulling approx 7K of boat and trailer, park for 10 minutes, and then come back start the motor and have full throttle like nothing ever happened. The throttle might not go out for hours again or it might go out in 10 minutes, but the cruise will always, always work. Around town I might go back n forth to work for a couple weeks and nothing happens, then all of a sudden $HIT---no throttle!!

posibility pedal is going bad

you are right the CC and pedal run on different circuits sounds to me like your throttle circuit is going bad but that is rare in any vehicle.. have you ever had any water in the motor compartment or control center? when you do hit the throttle dose the motor bog or dose it do nothing at all? what about boost any at all when this happens? smoke? anything out of the ordinary beside no power?

Never any water under hood or anywhere in cab. Not even excess snow on the floor mat in the winter. Mine does absolutely nothing to alarm you that it's going out---push down on the pedal and nothing when it happens. Truck idles fine like nothing is wrong. When the cruise is on and you go to hit the throttle you get nothing when this happens. Turn the motor on and off a couple or few times and it resets itself like nothing ever was wrong and no SES light. With falls cooler weather coming I'm guessing I'll go all fall, winter, and spring with no issue until we get to the heat / humidity of summer again---that's been the pattern. The dealer did say it throws a code for the throttle when I took it back in, but they can't find anything wrong with it. It definitely is a PI the A when it happens!!!

Yea i never had water under hood either. My boost just drops to nothing, throttle is no response, no smoke , or any weird noise, feeling or shaking just truck loses all throttle response. I coast to the side of the freeway and wait maybe 5 to 10 sec, and then back to normal like nothing happened. Mind boggeling.

You say you wait 5 to 10 seconds and all is fine? You don't have to turn the truck off at all? I get nothing unless I leave it sit for 5 to 10 minutes off or turn the ignition on and off a couple or more times to get it to reset itself and get the throttle pedal back. Damn thing did it today 2 times on the way to work which was the first time in a couple weeks. One thing about today was the outside temp was higher and the humidity is up some---this is one of the things I've noticed as a common factor when it goes out and the truck is up to full operating temp. I still think it's some short in the pedal circuit whether the TPS itself or something to or in the PCM, but that doesn't explain why it seems more affected on hotter and humid days. I've recently toyed with the idea of installing a slightly lower thermostat temp to see if anything changes.

2001 LT Crew 4X4 LB7 Stock--Westin Platimum Bars, Extang Bed Cover, LT265's

Yup I just pull off the freeway and then within a couple seconds its back to normal no turning it off. weird huh

Mine has been doing this lately while towing. It will be running fine then it seems to happen when I put the pedal to the floor then it will just dog out and the motor won't go over 2000 rpms. I'm pretty sure that it's the engine limp mode. I coast to the side of the road and shut truck off for a minute or two, start up and it's fine until it happens again. Only happens while towing. I'm fairly confident that it is my cp3 getting weak. I changed out my fuel filter thinking it was getting plugged, and also returned my PPE programmer back to stock in case that was messing with things, but niether helped. Seems to do it more frequently once the fuel tank gets more empty. I think the weak cp3 is starving the motor of fuel, and when it's not getting the fuel it's asking for, it goes into limp. Not sure if this is the same thing you guys are experiencing, but it sounds an awful lot like what's happening to me. I'm going to have my rail pressure tested with a tech 2 and probably replace cp3. Also I was reading back on some threads from awhile ago about this, and apparently a lift pump won't cure a weak cp3. It might help some but it won't cure it completely. Do a search on weak cp3 and read for yourself if you want. It really sucks, I know what you guys are feelin:(

well does it throw a code when it happens to you cuz i get no code and if it limps out. then it should throw a code right and i dont turn the truck off it just comes back within seconds of being at idle, stoped

That sounds more like a fuel supply problem which I'm fairly certain is not my problem. I get no bogging or anything and remember my cruise works just fine even when trying to accel with the cruise button---runs like a champ! My filter is brand new, but I did have a injection pump replaced under warranty several years ago and that was blowing a code causing the SES light to come on. Strange thing is that the truck ran fine then, but I don't think it would have for long.

2001 LT Crew 4X4 LB7 Stock--Westin Platimum Bars, Extang Bed Cover, LT265's

you might try replacing th TPS just to see if it happens again i know you did it once but maby you got another bad one... im a electronic engineer and humidity dose affect some electronics if it is high enough like 70% or higher but to my knowledge the motor companys stay clear of these kinds of circuit... last winter i was out playing in the snow and got some snow dust in my EC and shorted out my starter and AC but we are talking ALOT OF SNOW... well good luck and keep me updated if you get it fixed.

Thanks

Chris

We have a problem 01 like that at the shop, added a PPE lift pump upon his request, nothing changed with the limp condition, just made his weak FPR go out. Then we changed the MAP and BARO sensors, nothing changed. Then we put a PPE boost fooler/code eliminator on and it worked for about 200 miles then it limped again. I have looked at the charge pipes, no holes, no leaks anywhere, so I am thinking it's the MAF sensor. The customer has taken it to the dealer and nothing from them either, so I am stumped too.

I don't believe it has anything to do with a weak CP3 pump, as almost anytime it limps is is just cruising down the freeway (~5 psi boost) at around 70 mph (empty or loaded). You can drive it all over town and it will never limp, beat on it and it runs like a raped ape, no fueling issues at all when it is raced.

My symptoms were the same as this guys. Only happened when hauling heavy load.

Prior to the following, I have replaced every sensor on the truck.


You might try this.

Use EFILive to go into the Fuel Pressure Limits table.

Adjust Max to no more than 150 bar.

The limp mode stopped.

Installed new cp3, returned pressure to normal, no more limp mode.

good luck

My truck was lazy when towing on hills and at times would have no response for the approximate 10% of pedal around town. I had a dealer check all the above mentioned systems everything was in spec and graphed the accelerator pedal twice. My cruise worked pefectly also, cruise and pedal are 2 different systems. I found a pedal sensor online for $40. plus shipping, it made a whole different truck out of it. A different dealer explained it to me this way. The sensor has 3 curcuits in it 2 work from 0 to 5 volts and 1 from 5 to 0 volts. The ECM looks for the 3 curcuits to work together if 1 is out the ECM trys to work with the signal it's getting. If 1 curcuit fails the ECM defaults to idle so the engine doesn't run away. Yes if the pedal sensor fails it should set a code mine didn't. An easy and cheap way {2 10 mm nuts and 1 plug} to check would be to switch pedals with another truck and see if the problem followed the pedal. I hope this helps.

I've had a couple people mention the ECM just as you have here. Defaulting to idle is EXACTLY what happens to my truck when this happens. Absolutely nothing else shows up as a problem. I can stomp on the pedal when all appears normal and the truck runs like a raped ape. I don't have anyone to swap a pedal with, but getting a decent priced new or used one on-line has crossed my mind as a place to start with first. If my memory is correct when the dealer replaced it a couple years ago it really wasn't an expensive part---$80 is what comes to mind now.

2001 LT Crew 4X4 LB7 Stock--Westin Platimum Bars, Extang Bed Cover, LT265's

Ya, see mine only cutts out when towing about 7000 pounds, usually when im on the throttle and going up a grade where im in need of the fuel. It just cuts out, no throttle responce. See what boggles me is why no code. my dodge use to do this and it would throw a code everytime it did it. Has to be a ecm issue something im sure efi live could fix. Like i said my dodge did this and it was vp44 going out on me. Im in aww on where to start. Do i go with TPS, New Modified CP3 with lift pump, or just have someone fix with efi? All good choice, Just one problem $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

Here are a few cp3 threads.

http://www.dieselplace.com/forum/sho...t=Phantom+limp

http://www.dieselplace.com/forum/sho...d.php?t=250142 (http://www.dieselplace.com/forum/showthread.php?t=250142)

http://www.dieselplace.com/forum/sho...=248977&page=4

Cam Sensor
Crank Reluctor gear
Cam or Crank sensor ring.

my truck does this as well when towing.. stock or with tuner on... and it always seems to happen at 50mph. it does not throw a code, but when i go in and check for codes i get some random MAF codes tho

Ya i get the same randon maf codes and thats about it, no other codes. it suks so im torn in this hole thread its a toss up of tps, lift pump, etc. what to do?

MBDmax---can I ask where you found the throttle sensor on-line at for $40? Was it used on Ebay or a regular parts site and if so can you post the site? I've found a couple not searching long for similar prices, but only showing 2500 HD with the 6.0 gasser.

Thanks

2001 LT Crew 4X4 LB7 Stock--Westin Platimum Bars, Extang Bed Cover, LT265's
Offline

MBDmax---can I ask where you found the throttle sensor on-line at for $40? Was it used on Ebay or a regular parts site and if so can you post the site? I've found a couple not searching long for similar prices, but only showing 2500 HD with the 6.0 gasser.

Thanks

2001 LT Crew 4X4 LB7 Stock--Westin Platimum Bars, Extang Bed Cover, LT265's
Offline

http://www.rockauto.com/

OK, I know you have a new fuel filter, but sure sounds like plugged fuel filter problem. I suggest that you replace the fuel filter and then cut the old one open and check for debris and water. Only going to cost $20 and then you would know for sure. Lot cheaper than the other parts. :cool:

well a filter is cheap so i could just try that first, couldt hurt.

Mine has been doing this stupid throttle game for awhile now and that includes with the old filter last summer and the brand new filter this summer. Once again, if it were a fuel supply problem the truck would not run like nothing is wrong using the cruise control pulling 7K lbs. I'd be shutting down then as well for a fuel supply issue, but as we know the cruise operates on a different circuit and mine runs like a new truck when pulling or not using cruise.

2001 LT Crew 4X4 LB7 Stock--Westin Platimum Bars, Extang Bed Cover, LT265's

These things may not help but they won't hurt to try:

If you haven't cleaned your MAF sensor (takes a minute or two) you should.

Check your driverside inter-cooler downtube for a hole where it rubs the power steering lines.

Ok that's my small contribution. Now let's go back to listening to the guys who know a helluva lot more!

Good luck Pimpin'.

as far as the idle only issue,are any of you guys running k&n air filters?have seen many contaminated mass air flows from over charging air filter,also have changed 3 accelerator pedal position sensors in 4 months on seperate trucks for same problem.cruise operates off of different side of app that throttle does,watch app1 and app2 values with tech2 or snap on scanner,may not set a code if only partial failure of app,also check connector under dash at app,might have been kicked or floor mat compromising integrity of connections

Stock filter on mine and just recently changed along with the fuel filter changed. I'm suspecting APP more than anything else and like you say---partial problem with APP won't necessarily throw a code or SES light which is how mine reacts. I can sometimes go days or a week or more with nothing, then it will happen 2 or 3 times in a day and REALLY P's me off!! Seems to be more suspect in hot humid weather, but not 100% of the time. I don't believe a fuel problem as some suggest because of cruise working perfect whether towing or not and when throttle resets itself after it goes out the truck runs like a raped ape like nothing ever having happened. I'll take your advice and check the connections once again. This time I'll unplug the connections and make sure they are clean then re-plug since it can't hurt to try. The fact that you mention changing a few of these acting the same is interesting because I've read elsewhere that they seldom go out, but this suggests it's not that uncommon. Thanks for the help!

2001 LT Crew 4X4 LB7 Stock--Westin Platimum Bars, Extang Bed Cover, LT265's