Need SR help BAD!!! SR will not stop getting lean on wideband and idles bad???

[mikesloud]

I have sr20det redtop in 93 240sx , It ran fine for 3 months on stock stuff,upgraded ecu twice, once with a 300zx tuner , then retuned at jimwolf , I have Z32 mafs, 50lb injectors, I have exhausted my self doing different manifolds, turbos , new pipes, bov, I cannot figure out what the heck is wrong!!! I have no place in town that can help either!! I have replaced part by part, I have super AFC2 , set at 1 in 1 out , I have tried 2 in 2 out and even without afc it still has problem. It idles like it has a miss or leak, but keeps leaning out to 14.8 -17 at idle , even if I turn fuel up to 50% it will get rich then turn lean again!!! Fuel pressure is fine ,pump fine. At wide open throttle it pulls good then stutters, like it has a boost leak, but cannot find it , it is not piping , could it be a manifold leak , injectors?? what else to try??vaccuum is at 15-16 at idle ?? I am tired and have no help !!

please reply with suggestions what i can try next?? it acts like a vaccuum leak , wont start and idle right!! you guys are my only hope besides driving 7 hours to a place in dallas!!

[mikesloud]

timing is fine by the way , I am so frustrated!!!

please help!!!

[Onizuka]

Wow, seems like quite the predicament.

Concider this:

The amount of fuel your motor gets is based primarily on the throttle posistion and measured airflow verses the rpms the motor is at. If your throttle posision sensor is not functioning it could be telling your ECU that the throttle is closed the whole time.

By the way, you WANT to be lean at idle (and when cruising). Rich conditions should only happen under acceleration and 12:1 should only be acheived at wide open throttle.

[pgt892]

Your idle vaccuum pressure sounds little low. Like JSpec said, if you are having unmetered air enter the engine via a leak, then that may be your problem. Try pressurizing the system and see if you can hear air escaping anywhere.

[mikesloud]

I can try to pressurize the piping and intercooler , how can I check past throttle body without taking intake off?

[S13240]

I can try to pressurize the piping and intercooler , how can I check past throttle body without taking intake off?

I believe you hook up a pressure gauge with a compressor and pump air into it to see if anything is leaking internally. Something like that!

[mikesloud]

Is it possible to have a blown head gasket that would cause it to lean out like that? Or intake gasket?? There is no water in oil or viceversa . it looks fine. I do not know what to do!@!

[biglipzit]

you can rule out a boost leak for sure cause if it was leaking boost it would run too rich. It might be your throttle position sensor like previously suggested. You should check that first. clogged injectors maybe? Could be that.