LB7: Engine Starts and instantly dies

[tpijeep]

I have been battling this for a while and search has yielded no results. On occasion I will start my truck and it will fire and die in under a second, then you have to crank it about 3 times longer then normal for it to run normally. It generally does this when hot but not always.. I just put a new set of injectors in it because i had all the symptoms of injector failure, it now runs perfectly but today it pulled its no start trick.

After 2 days of wrenching it was dishearting to have it die again...

 

[messejme]

the plastic bleed screw on the fuel filter housing may me leaking air into the fuel system

 

[TheBac]

Could be the filter isnt quite sealed, too. May also be a very small air leak in one of the rubber fuel lines.

 

[tpijeep]

Okay, I am doing a H2O/Meth kit today, I will check the hoses, filter is new, didn't know if a leak on the low psi side could cause this. Thanks..

 

[S Phinney]

Does it set any codes? Sometimes the ignition fuses under the hood loosen up and doesn't make good connections causing similar problems.

 

[tpijeep]

No codes, checked the filter, checked the lines on the filter, went to real hose clamps rather than the factory clamps, still had the no start once after.. Dealer claims they have never had that issue, this was after they denied my injector claim at 117k

 

[StrobeLite]

Check your cam sensor. Sounds exactly like a problem I had.

 

[Max Power]

Are you sure it's not a passlock security issue?

IF you have EFI Live, try disabling VATS and see if that fixes it.

 

[S Phinney]

Are you sure it's not a passlock security issue?

IF you have EFI Live, try disabling VATS and see if that fixes it.

Thats what I was talking about with the fuse issue. When it loosens up the ecm thinks someones trying to steal it and shuts it off. If it's that fuse disabling the VATS will not change anything though. To check it out it will be harder to find. See if your door chime changes sound while wiggling the ign. fuses under the hood.

 

[tpijeep]

Double whammy here, no EFILive and the factory door chime was removed when I got rid of the factory radio.. I have never seen the Vats light flash when it did this so I am not sure... any other ideas with the cam sensor?

 

[ncalmax]

I hate to bring back an old thread but I have the same thing going on.
2004.5 duramax

Here is a quick run down of mine situation. It started doing this last summer when temps were over a 100*. If I shut the truck off when it's over 100* it will do it every time. Run for 15-20 secs then shut down(loses fuel preasure). It also does this if I shut it off if it's below 35*.

So now that it is starting to warm up it now does it when I shut it off at 85* and hotter. If the temps are between 35*-85* it will start fine every time no issues.

I have replaced two fuel filters I took it to the dealership they checked the housing and all around that area for leaks and found nothing.

Hope someone can help it's getting very old having to prime it back up.

 

[dmaxfireman]

if priming it starts the truck you are either drawing air or bleeding off pressure.

is your truck stock?

 

[ncalmax]

No not stock just a bullydog programmer and straight exhaust.

 

[duramaxGMC]

My truck is doing the exact same thing. The temperature over 85 is the same also. I prime the air out and it starts up after a few seconds every time. It is getting air in the fuel line from some where. I am going to replace my bleeder screw first. ???

 

[wes06dmax]

There is a line next your prime pump that looks like a spark plug line make sure it is all the way down I have a friend that had the same problem and we tryed everything i was getting agravated and just touched it and it made a clicking sound and it has run fine ever since

 

[ncalmax]

Thank you wes06dmax for the info. I checked mine and sure enough it was up a little bit so I pushed it back down. But it's still doing the same thing.

Has anyone had their filter housing leak at the actual pump housing under the torq screws. I might have seen some diesel there before on mine. I had it at the dealership a few months ago to test the housing and they said it was fine.

Still a very annoying problem

 

[duramaxGMC]

I am still having the hame problem too. New filter with O rings and bleeder screw.

 

[Vasbinder]

My water sensor on the bottom of the fuel filter had a hair line crack and sucked air. I could'nt see the crack but it sucked air and left me stranded on side of the road.