2004 Duramax LLY Air in Fuel

[MAXIMUM69]

My '04 Silverado Duramax LLY just broke 100K miles. It has been a great truck, but recently started something that has be a bit confused. When I park it with the front higher than the back, even slightly, it gets air into the fuel system and I have to bleed it at the filter housing to start it. If I park it with the front end lower, it starts right up.

I read several threads here including this one:

http://www.thedieselpageforums.com/tdpforum/showthread.php?t=36784&highlight=duramax+fuel+filter+air

I also took it to a shop that specializes in Duramaxes and he told me the same thing. He said that I could replace the filter housing and all would be cured. But he suggested that I install a FASS auxiliary lift pump and NOT replace the housing. I am reluctant to go blow a bunch of coin without knowing for SURE what the problem is.

Am I on the right track here in terms of the problem and should I replace the housing or just install an auxiliary lift pump?

Thanks in advance for the help....

[Kennedy]

I would highly recommend the addition of a lift pump although I prefer a quite different setup than waht was suggested to you. Simple, quiet, efficient Kennedy Twin pump setup. If your filter head is leaking it will then leak externally, but I doubt that it will.

[MAXIMUM69]

Thanks much - for now it seems to be working. I replaced the filter, WIF sensor, bleed screw and hose clamps. After that, it fired right up, but I just completed it tonight. I like the look of your lift pump, though, and it's priced right.

[More Power]

If the problem continues, try loosening the fuel filler cap, then run it loose for a few days to see whether a poorly vented cap might be contributing to the problem. A cap that holds too much vacuum (like after an overnight shutdown) could make a minor air leak in the fuel supply system much worse. An air leak still needs to be eliminated, but....

Jim

[denber]

I have a 2004 6.6 Duramax, LB7,which will barely pull itself. It will not reve over 1800 rpm and there is a lot of light blue almost grey smoke out of the exhaust. On a scope there are no codes and the duration of opening is almost exactly the same for all 8 cylinders. Could alot of air in the fuel cause this problem?
Would love some opinions.

Thanks
Denis

[denber]

I meant to say no codes and the duration of opening of the injectors is almost exactly the same on all 8 cylinders. The truck has 270k and all 8 injectors were replaced at 200k and then 4 on the left bank were replaced at 243k due to fuel leaking into the crankcase.
Thanks
Denis

[More Power]

Here's a link to a fairly recent forum thread that discusses how to test for an air leak using a modified cap.

http://www.thedieselpageforums.com/tdpforum/showthread.php?t=43065

Aside from the modified cap, we've been recommending the same procedure since the 1990s. A tightly wrapped oily rag can be effective to seal the air hose well enough to allow testing.

Jim