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Running lean on stock sr20det

17495 Views 17 Replies 7 Participants Last post by  wussmonster
I am running extremely lean on a stock sr set up my aem wide band gauge is maxed out at idle and when cruising the gauge reads in the 16s.. I am running a walbro 255 fuel pump and getting 40 psi fuel pressure. I have already checked timing cleaned maf checked voltage coming off the maf and smoke checked for vacuum leaks all injectors are firing. The problem is causing me to stall out when i shift into neutral. Could the sr o2 sensor be bad?
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It maybe the 02....
U should check the obd...
Idunno when i did my swap i connected the check engine lite wires so i could check the o2,and the codes...
Turn up ur fpr 2 43psi...and see wat happens..
The point of having a adjustable fpr and wide band is u can play with the setting ever so slightly and runnin a little rich wont hurt anything that much u may even spit fire out the exhaust...i kno i do...
Sounds like a vacuum leak.

its not fuel pressure i have had the fuel pressure up to 50 psi and hardly any change in the afr. There is no vacuum leaks it pulls a full vacuum on my gauge and also i have checked for leaks with a smoke machine and found nothing. It is frustrating i just want to get out and drive it!
Do you have an open-air BOV? This will cause you to stall out like you are describing, if you went from your stock re-circ valve, to an open air BOV.
I do have a open bov but that wouldn't cause my car to run lean all the time.
An exhaust leak could cause your wide band to read lean.
I do have a open bov but that wouldn't cause my car to run lean all the time.
nooo, but it will cause your car to stall when shifting to neutral. As for running lean, what other fuel mods do you have, besides a fuel pump and FPR? Do you have any kind of tune or air-fuel controller? Also, when are you reading 40psi on the FPR gauge? With vacuum attached or not?
The rest is stock. I have 50 miles on the car after the swap just trying to get everything running right before I add any fuel management. I was reading the fuel pressure at idle when the vacuum was attached. I have also noticed my vacuum gauge fluctuates between 15 and 20 at idle and i know it should be 18-20 but I tested for vacuum leaks and could not find any.
your vacuum gauge? or your boost gauge?
well its the boost gauge but it reads vacuum too.
vacuum system leaks will usually make you run rich, not lean

Arent you supposed to run really lean at idle?
This thread is confusing
^^^Yes, I too am confused, just trying to get him to lay it out a little better.
ok my thoughts are that the car is running lean causing it to stall. when idle the vacuum moves around from 15-20 on my boost gauge (vacuum side) when the vacuum is pulled down to 20 (where it should be) the afr is able to be read and it is around 16-17 still very lean... i do have a atmospheric bov but that would cause the engine to run rich for a moment (when shifting) and it doesn't as soon as i let off the gas and shift to neutral the air fuel gauge reads straight lean. when cruising down the street the afr reads upper 14 to 16 and i feel that is still very lean. I pulled the plugs and they were white so the gauge is reading correctly.
then ur fpr isnt werking rite 50psi on fpr is stupid rediculous cause ur runng injector so close to the height of their duty cycle...
im at 43psi and im running rich.....
i have an atmospheric bov wit no probs.....and im rich in boost and lean out when i let off...
nissan motors have a tps control that controls f/pump voltage.....when u let off it lessens voltage..when u wot it increaces....
so i have tested voltage on maf (1.6v idle stock maf), tps (.5v at idle), o2 (.03V at idle extremely lean), and water temp (i dont remember the exact voltage but it was in spec with the fsm) also when in safe mode (maf unplugged) it seems to run a whole lot better infact it runs rich in safe mode with an my vac reads 20 in-hg in safe mode instead of 15 in-hg the o2 in safe mode reads .8v. I have no idea what it could be since all my sensors seem to be reading correct. I appreciate any input i can get.
my car runs as driftsyndicate states as well. rich in boost and when i throw it in neutral it leans out. i've also seen AEM widebands read about 1-1.5 off when compared to the A/F gauge on a decent dyno.

personally i don't think this problem is causing you to stall out when shifting into neutral after building up boost. re-circulate your BOV and tell us how the car responds.
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