Vrank

iTrader: (4)

Incorrect. Bpu will not affect this. You have other problems. I guarantee. You're masking problems. I've done a holset/fmic/intake/exh on 3 of my personal cars, as well as countless customer cars with different brand turbos, this doesn't affect that.

megamax

iTrader: (9)

so explain to me how I can mask a leaning problem when there is more air flow and not enough fuel(hence low stock fuel pressure/small injectors)??

there is no vacuum/exhaust leaks, if there is more air then fuel then it will lean out in throttle. if you press the pedal and the numbers come down, then it's your stolic idle pressure that is the issue.

Vrank

iTrader: (4)

Okay buddy, believe what you want. How come everybody with a single and stock regulator doesn't have these issues? How long has your car been running?

Ali SC3

iTrader: (10)

The stock fuel pressure regulator is almost never the problem, and you don't really have that much airflow at idle if anything you have a restriction on the motor off idle. The ecu always adjusts to perfect AFR if you don;t have enough air flow you will have a very low idle, that is about it. on the aristo ecu I can turn my throttle body down to where it idles at 4-500 rpm's and shakes but the AFR is always dead on. Vrank is right a fuel pressure regulator of the adjustable variety would mask the problem and is a good way to risk having to worry about a fuel leak for no reason. its gotta be a fuel problem like the injectors or the o2 sensor not homing in, or you could have a cloggged injector or a downpipe leak triggering a false lean, whatever it is its not the fpr those a bulletproof even on the n/a motors. IF you rewired the o2 make sure the shielding is not touching the main signal part of the wire or you can also have that same problem as the factory shielding is grounded.

99SC42

iTrader: (44)

It sounds like an ECU Problem to me to be honest...

Get another ECU and see what if that fixes the problem.

smiley954

i got it rebuild at driftmotion but if i can get another one i will try that

Ali SC3

iTrader: (10)

I actually do see a 17 afr on mine only on a hot start and it goes away pretty quick. toyota's fix for that is a vsv to increase the fuel pressure but its really not needed so check the work you did with the fuel pump and bypass.

also I just remembered if you are popping you could have some misfires for one reason or another, and that might show a lean reading on the wideband since the air in that cylinder doesn't get burned and shows up on the o2 sensor (and the fuel pops in the exhaust). did it ever idle right or is this the first time running the motor? compression test? check coilpack connectors? bad injector? anything that would cause it to missfire? it really does also fit a bad ecu also.

turb0g33k

It's called Electronic Fuel Injection. It is impossible for an only a FMIC or exhaust to cause a lean out like that. That's what MAP/MAF is for.

Something beyond the control of the computer is causing this.
Did it previously run fine and for how long?
Is the wideband now feeding the O2 signal to the ECM in place of the OE O2S? Is the ECM setup for this? Did it start doing this once you installed the AEM wideband? The details are a little vague.

megamax

iTrader: (9)

over a year now..