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Can anyone tell me what the butterfly in the photo does for the operation of the duramax? I know that the diaphram in the picture is the EGR Throttle Valve Diaphram, and it is attached to the butterfly and actuates it, so Why is there a butterfly here, and when does it cycle/Have to do with the EGR Valve? I only posted the link to the Ebay Auction, because I can't figure out how to insert a picture in this thread, so I thought I could just give the link to look at it.

The reason I am asking is because when I have the vacum line hooked to the vacum diaphram and the engine is warm, my truck runs like crap, and as soon as I disconnect the vacum line, the diaphram looses vacum, and the valve springs back to I believe the closed position, and the truck runs smoooooth as glass. WHY?????
 

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No linkey or is that linky? Oh well, there is no link in your post.
 

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Discussion Starter #3
Sorry for that..
John
 

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Throttle body? We don't need no steenkin' throttle body! I don't know what this seller is thinking or even if they know anything about diesel engines. That looks like an intake runner, and the MAF is certainly standard on a DMax, but the only reason that I could see for the butterfly and vacuum operator would be an air shutoff, required in some industrial and oilfield operations to prevent engine runaway if ingesting flammable gases/vapors. It is definitely not a "standard application for early DMax engines."

On edit, it may have something to do with EGR, I don't have an EGR engine so I may out of line here. If you have what you say is going on with yours, I'll wager the line CLOSES the butterfly to pull from the EGR and when you disconnect your line your butterfly OPENS on spring tension and you are getting unrestricted clean air and run better than when "sucking" exhaust gases with the line attached and the butterfly closed.
 

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I got a set of feed lines from that seller on ebay. His stuff was dead on for me. He saved me alot of money. Check the application for that part though it may be for a newer dmax(lly,lbz).
 

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That valve shows up in my 2000 Isuzu NPR 4 cyl's too. It is part of the engine braking feature, I believe. It controls airflow during engine braking to mute the noise.
 

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Idle_Chatter;1602602; said:
On edit, it may have something to do with EGR, I don't have an EGR engine so I may out of line here. If you have what you say is going on with yours, I'll wager the line CLOSES the butterfly to pull from the EGR and when you disconnect your line your butterfly OPENS on spring tension and you are getting unrestricted clean air and run better than when "sucking" exhaust gases with the line attached and the butterfly closed.
That's it.
 

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Discussion Starter #8
OK, now we are starting to get to some more troubleshooting with my engine. That valve is from a 2003 DMax with the EGR valve, I purchased a EGR and Cooler from the guy, and it was BRAND NEW. I swaped the EGR with mine, but it did not help my condition. So if I run the vacum line off of the EGR Throttle valve diaphram, it is in the open position? From looking at the picture, it is closed, and that should be the spring loaded position, and vacum opens it?
OK here is the senerio, with the vacum hooked up to the diaphram.
Cold start, idles fine, runs fine, no CEL at all. Drive and get it to operating temps and them comes back to idle, it runs rough, I can throttle it back up and up at say 1300 rpms or higher, it is as normal, but under that it is rough and sounds like a gasser dieseling when you shut the key off. Remove the vacum line and it smoothes out, but let it continue to idle, for about say 30 seconds and the CEL will come on with P0404 EGR PERF CKT OPEN. If I just idle it up 50 or so rpms, I will never see the light.

Again, the EGR has been swapped out for a BRAND NEW one, and I even installed a blocker plate at one time, but it just threw more codes. I am not looking at buying that part, because mine does work, I just wanted to stir someones mind to see if I can figure this out.

WannaDmxsub, I know you have seen me ask this question before, but I still have not figured out how to fix it.
Would EFI Live work to shut down the EGR system and stop all of the EGR Lights?

Looking for any help on this, it iskicking my Rear.
 

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I don't have EFILive but I believe you could get it not to set the codes.
Trace the vacuum line and see if there is anything obviously wrong.
The service manual has 3 pages for that code, P0404, in my 04 book. I tried to scan them for you but it didn't work... if you don't want to get the hard version see if you can find one of those cheap electronic versions on e-bay. Just a note, there are 3 or 4 tests for that code that require a TechII to command the EGR system.
 

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Discussion Starter #10
OK, I'm listening, how do I get it not to set the codes? I will trace the vacuum line in a few days, still recovering from the back surgery, and I would really like to see what your book says on those 3 pages, what manual do you have?

Also what cheap electronic version are you talking about? I know my way around Ebay, so please just give me some key words to work with, and I can search it from there.

Thanks for all the help so far AGAIN, but I really want to know why is this therowing the code, then I want to make it go away.
 

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Sorry for that..
John[/quote]

Oh, easy, thats your choke. It's for cold starting.



:joke:
 

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Helminc.com is the best place to get the manuals. I tried a search on e-bay for the disks and didn't find anything...go figure???
 

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Discussion Starter #13
OK, an update.

Today, I KILLED the cat, and straight piped the muffler, and man does it sound good, not to loud, but a grumble to let everyone know you are there, anyway, the check engine light I have been getting, is GONE! So far anyway, so my question is, could the cat be clogged up to a point that it would have thrown the code? (P0404) Maybe the muffler? I do not know, but Imy next step is to reconnect the vacum line to the EGR Throttle Valve diaphram, and see if it runs rough when it warms up. Maybe it is fixed for good, at least I hope so.

Just wanted to throw the update out there, Man do I Love my truck!
 

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Tolliwacker;1625358; said:
so my question is, could the cat be clogged up to a point that it would have thrown the code? (P0404) Maybe the muffler?
Interesting...How many miles on the engine?...Haven't some EGR solenoids gone bad, or is that mostly a LLY issue?

To answer one of your earlier posts, YES, EFI Live will fix all of your troubles :D
 

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Discussion Starter #15
174,000 and counting.........
I would think that since my truck was one of the first to get the EGR and Cat, I think it was just something sensitive to pressure, maybe... the code is for EGR Open I believe, but all of this is speculation, and I have not put enough miles on it since the cat delete to know if it is gone for good.
 

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Dumb question, but what trucks (years or sales location) have cats?
 

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Discussion Starter #17
Mine was bought and lived in TX, but it was a cali equipped truck. The Cat and EGR Started in 03 I believe, since some people argue that the LB7 Did not have the EGR and Cat. As for location, I guess some cali equipped trucks went to other than California
 

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Our Cali '02 came with a cat & EGR...One of them is gone, the other doesn't function properly :D
 

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Discussion Starter #19
OK, My CEL Came back yesterday, only after I reconnected the vacum line to the EGR Throttle Valve diaphram, afer the truck warmed up, and I came back to idle after slowing to make a turn, the truck ran the worst it ever has. Smoked like a sod fire, and rattling it's guts out, I could not even feather the go pedal and get through it like in the past. I did not shut the truck off, and just pulled the vacum line and plug it, and all back to normal, smoke cleared up, but the CEL is back, for the P0404, after letting it idle for more than 30-40 seconds after it is at operating temps.

Could it be a bad MAP Sensor? It is mounted on the item in the pics at the first of this thread.

OH Well, guess I will just live with it, until I get the change saved up for the EFI Live.

Please anyone, I just want to know what the problem is, I have this Phobia about everything working as advertised on my truck, it runs Great, as long as I do not have vacum to the EGR Valve Throttle Solinoid.
 

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Tolliwacker;1629864; said:
OH Well, guess I will just live with it, until I get the change saved up for the EFI Live.
Well, it's not that I don't want you to buy our product, but, if all you need taking care of is a few code issues perhaps look at a few of the vendors on here that use EFILive for tuning (I won't name them because I know I will forget someone!), but, maybe one of them might be really nice and cut you a good deal to just get the ECM programmed by them with those codes shut off.

Cheers,
Ross
 
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