car running lean under boost

U

usetaboost

SAY CAR RAMROD!!
Joined
May 4, 2005
Been battling this for some time now. Alcohol pump is producing over 200psi, fuel pressure is rising and holding under boost, chip is setup for car. I got a redsxp pump witha hotwire kit. I got 55lb injectors. Maf seems to be reading and pegs at 255, tps runs through voltage nice and smooth from what i can see, everything looks normal. I can't even run anything close to what the chip is set for. I even changed out the methanol. 02s drop like a freakin rock with any real amount of boost. cross counts are cycling and everything. Fuel rail holds psi with key on while sitting. running an lt1 maf and translator, translator is set to where it should.

at idle

iac is around 10
blm is 126
02s low .800s
maf 7
fuel psi with liine of is 45lbs

I'm running a stock 237 regulator. no weird psi swings that I could see, everything looks good. I even tested it in the garage with compressed air and psi went up accordingly and the road test looked fine.
 
yeah a little. Today when I went through everything the 02s dropped so far the car popped
 
Find a known good MAF (not a reman) and see if that helps. If its bad it will lean it out at WOT. I thought mine was good until I did this. Solved it right away
 
usetaboost said:
Been battling this for some time now. Alcohol pump is producing over 200psi, fuel pressure is rising and holding under boost, chip is setup for car. I got a redsxp pump witha hotwire kit. I got 55lb injectors. Maf seems to be reading and pegs at 255, tps runs through voltage nice and smooth from what i can see, everything looks normal. I can't even run anything close to what the chip is set for. I even changed out the methanol. 02s drop like a freakin rock with any real amount of boost. cross counts are cycling and everything. Fuel rail holds psi with key on while sitting. running an lt1 maf and translator, translator is set to where it should.

at idle

iac is around 10
blm is 126
02s low .800s
maf 7
fuel psi with liine of is 45lbs

I'm running a stock 237 regulator. no weird psi swings that I could see, everything looks good. I even tested it in the garage with compressed air and psi went up accordingly and the road test looked fine.
Click to expand...
How much boost are you running? What chip. Has this set-up worked correctly in the past?
 
At wot the boost is around 21lbs. When I roll into it, it starts going lean around 17lbs. Voltage is 14 at boost. Back when I had the 42lb injectors I couldn't even get past 21lbs. Swapped injectors and ran 23 just fine. Over the summer it seems like it has been inconsistent. Some days I could run 26lbs just fine, other days I had to turn it down. Seems like the problem has slowly been getting worse.
 
at 6pm I went out and flipped the key on to pressurize the fuel system. Got back about 10 minutes ago and had just over 15 psi still reading on the guage.
 
Air quality ad temp can make quite a difference in how the car runs but it sounds like something mechanically or electrically is the problem. I was thinking maybe you have inconsistant gas? But, I doubt thats the case. Then I was thinking maybe a weak alternator? But if voltage is staying consistant, that rules out a bunch of problem areas. I thought maybe the socket on your "voltage" bulb was getting lose or corroded.

I dont know man, I think I would try a known good regulator. Then a known good MAF. I didnt even think about the O2 sensor, thats always a good one to change anyways.
 
Well I can try the maf off the grand am, I know that's good for sure but that's probably not it. Bob mentioned that i should check the voltage going to the pump. Anyone know which wire it is to check? I can check that out tomorrow and I'll make sure the ground has some good bare metal grab on to.
 
I'm gonna order a diaphram for the regulator. I want to check everything I can in between that time though.
 
Sounds like the pump is shot and or voltage/ground issues or the chip doesn't have enough pulse width where you need it
 
Have you tried bumping the fuel up in the Chip?
Oh yeah again... What Chip?
Turbo?
Heads?
 
LOL I was just gonna send you a link to this brian. So you think maybe it's not so much a pressure thing, but volume? I too still think it may be the chip but I wanna check all posibilities before I send the chip back to eric. Can you tell me which wires to probe on the harness or do I need to get right to the main wire on the sender? What is the walbro supposed to put out gallon per minute? You're gonna have to dumb all this down a bit so I can diagnose it. I'm at home right now so I can do the wiring checks at least.
 
Even still, at part throttle when I'm not even at wot it bucked hard today, thought I killed it...knock on wood for the 5th time
 
Has the chip been re-burned after switching turbos?
 
yup. The only thing that has changed is the stall. I had to have the chip burned because I switched to the 55lb low imp injectors and modded ecm while you had my turbo. When I had the 42lbers in I couldn't get much more boost than what i had now on safe tune
 
Email Eric and find out the pulse width after you verify pump/wiring is ok
 
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