ok guys i need some lean idle help.

well recently i rebuilt my turbos, added 1 stage colder plugs, and the car was driving around fine, then one day it started to idle at full lean. the only way for me to get the AF to 15 where i have it set for is if i 0 out my afc at my 800rpm setting. the stft are at like 0 and -2. im getting 15-16 spark timing at idle. but when im driving the car seams to run perfect. still hits 11.0 Af at wot at 20psi.. ok so i figure for some reason my car is pulling fuel. so i went back to my 450cc injectors, i replaced the plenum gasket my outer electrode of my spark plugs are white. my oil was thin from gas getting in so, for some reason i was running rich and the ecu is deciding to pull fuel im assuming? i have normal idle speed, and if im crusing at just coast with clutch in, it seams to stay at about 15.2 AF where i have it set for. but as soon as i come to a stop it idles at full lean and the exhaust starts to pop a bit. any ideas of what it could be? i also noticed a crack in my manifold before the turbo, idk if that has anything to do with it or not.

well recently i rebuilt my turbos, added 1 stage colder plugs, and the car was driving around fine, then one day it started to idle at full lean. the only way for me to get the AF to 15 where i have it set for is if i 0 out my afc at my 800rpm setting. the stft are at like 0 and -2. im getting 15-16 spark timing at idle. but when im driving the car seams to run perfect. still hits 11.0 Af at wot at 20psi.. ok so i figure for some reason my car is pulling fuel. so i went back to my 450cc injectors, i replaced the plenum gasket my outer electrode of my spark plugs are white. my oil was thin from gas getting in so, for some reason i was running rich and the ecu is deciding to pull fuel im assuming? i have normal idle speed, and if im crusing at just coast with clutch in, it seams to stay at about 15.2 AF where i have it set for. but as soon as i come to a stop it idles at full lean and the exhaust starts to pop a bit. any ideas of what it could be? i also noticed a crack in my manifold before the turbo, idk if that has anything to do with it or not.

The crack can do it. I would first eliminate that problem before pulling your hair out trying to find something else. Any leaks before the O2 sensors can cause some weird a/f ratio readings.

ok well heres the thing. im running open o2 housings at the moment. and my wideband is in my front o2 housing and the crack is in the rear manifold. idk if that has anything to do with it or not. vac leaks usually cause an increase in idle speed and a richer condition, i idle at normal idle speed.

The placement of the wideband is null. If the crack is before a factory o2 then the ECU is going to freak out hence giving you your crazy idle AF.

The placement of the wideband is null. If the crack is before a factory o2 then the ECU is going to freak out hence giving you your crazy idle AF.

so do u think my manifold crack is the culprit?

Sounds like it very well could be.

It could also be the fact that you aren't running a downpipe. Put one of those on... please

Oooh, good thought Hans.

I remember IPO having a lean issue on SL-T and it turned out to be caused by the positioning of his wideband and the open dowpipe.

Running no downpipe is a good way to crack valves.

yea. im working on making my downpipe. but how can that crack valves?

I believe it has to do with the properties of metal and the vavles being hot and cool air being allowed back in and cooling the valves too fast.