05GMC4.8

Before my 80e swap all was good as far as fueling, but my truck sat for about 3 months before i could get it back on the road. During that time i swapped in a used 08 silverado flex fuel pump and a fpcm from an 08 flex fuel suburban. obviously i couldnt drive it but it started and pressures were just like before the pump swap.

Once the shop put in the 80e they took it for a test drive but forgot to hook up the power wire for the oil return pump and they said white smoke was going everywhere and once they got it back there was a puddle of oil on the ground under the turbo (rear mount). once i drove it home it was stumbling so i pulled the charge pipes and there was oil all inside them and in the intercooler. i cleaned everything out and ran seafoam thinking the intake was dirty from the oil. that didnt work. I checked for leaks boost and vacuum and have not found any. it builds boost to 6 psi like before. i was thinking maybe the seals on the turbo went bad and is letting oil into the intake still but im not finding any more oil in the charge pipes.

It idles fine and cruises like normal. Fuel pressure according to my auto meter fuel pressure gauge hooked up at the rail is about 44 or so at idle and cruise and when i get on it pressure jumps to 58-59 psi. But once pressure goes up, my truck goes lean and stumbles. If i go more than half throttle while crusing or while going up a hill it stumbles there as well. ive pulled the injectors and ohmed them out (all about 12.5 ohms) and noticed one was gummed up inside, so i replaced it thinking that was my problem and it didnt solve my issue. I get no codes and i took it back to the tuner to see if he could see anything, he said its going lean on the drivers side. i can also see it goes lean on my afr gauge but cant tell what bank it is. I attempted to put the stock pump/fpcm back in but on start up it wouldnt build pressure so i figured the pump died.

ive replaced the plugs, and the drivers side O2 sensor and that was no help either. that did clean up the idle some but it was already fairly smooth. now im thinking that the used pump has a dirty fuel filter in it so im looking to put a new pump unit in it unless yall think it could be something else. i want a stock type pump that i know will last. i attempted to take apart my stock fuel pump assembly but im pretty sure i destroyed it or i would just put a walbro 450 in it. i've also looked for loose electrical connections but no luck there. Im stumpped!!

i was looking at airtex website comparing pumps and they had technical data with flows and pressures of their replacement pumps, but wasnt sure which to get. heres some info on the pumps for crew cab models:

2007 -2008 5.3 non flex fuel pump -Turbine type, GPH (Free Flow) 70-80, Max Pump PSI (Not System) 85-95
2007 -2008 5.3 flex fuel pump -Rollervane type, GPH (Free Flow) 65-75, Max Pump PSI (Not System) 85-130

The pumps have different flows for the 2009 and the 2010-2013 trucks too tho

2009 non flex fuel (4.8, 5.3, 6.0) - turbine type, GPH (Free Flow) 70-80, Max PSI (Not System) 90-100
2009 flex fuel (5.3, 6.2) - turbine type, GPH (Free Flow) 60-70, Max PSI (Not System) 55-62

2010-13 lists only flex fuel but 3 diff models with different flows,
E4005M (4.8, 5.3, 6.2L)- Turbine type, GPH (Free Flow) 100-110, Max PSI (Not System) 95-105
E4008M (4.8L, 5.3L) - Turbine type, GPH (Free Flow) 120-130, Max PSI (Not System) 90-100
E4009M (4.8, 5.3L) - Turbine type, GPH (Free Flow) 120-130, Max PSI (Not System) 85-95

seems like the 10-13 pumps are better but whats different that makes them special for those years? different electrical connectors? I would just get the E4008M if i knew it would plug in and work since i have both a flex and non flex FPCM.

Any help is greatly appreciated

FFDP

iTrader: (2)

All I can tell you is that you never want to buy an airtex pump, ever.

They are nothing but pure junk, we won't even put them in customers cars at work because we do not want a come back.

05GMC4.8

better of getting a new ac delco unit then? i believe they arent much more cost wise

07NBSChevy

I agree 100%. Longest i had one last was 6 months before failing.

Tig

iTrader: (2)

Like said, Airtex is junk. Mine lasted a few months and I was back at it again.
Went with a Delco and has had no problems since.

Have you checked all of your injectors? If one was gummed up, more than likely the others are to. Check them out and see how they look.

05GMC4.8

yea i was sure to check them all once that i saw that one. ive had the injectors out 3 times now and that one was the only one that looked nasty just by looking down into the inlet of the injector. whats weird is that im not getting any misfire codes and it feels great up till about 50% throttle/load or so.

could a faulty bov cause this type of issue? its a greddy type rs, ive tryed tightening up the set screw on it some thinking it was opening some under boost and and that was no help, but i dont ever hear it open up when i let off the gas, just the wastegate opening and closing sounding like flutter which isnt good for the turbo