air fuel lean rich, uhh. damn.

[jynxtrix]

Right, so the car is running now. It idles really lean (in the red), but goes green when driving. (please don't flame me for using a narrowband A/F Gauge, it's all I've got to work with at the moment). I've heard and read arguments both ways one this. that they are worthless, and that they are better than nothing, whatever the case, it is my only basis for judgment at the moment.Under boost, she remains rich, but stumbles. I'm not entirely sure what to make of this.My current setup probably isn't ideal either. ca18det in an s14 with a stock ecu, vafc (yes, i know, honda, but it was laying round, so I'm trying it out...) stock s14 fuel pump, and a t-25 turbo that smokes out the exhaust and the turbo when I give it gas(hopefully I'll get the rebuild kit for that this week)It runs like crap cold, for about 2-5 min, then idles and drives fine aside from the stumble at 5 or so psi.when she's cold she idles rich (normal i know), but once she warms up it's all lean idle. I need a better FPR, mine is stock, but that will come a little later. Any Ideas? I started out on chevy's as a kid. Carbs are my best friend. Fuel injection is starting to piss me off.

[zero_gripS13]

pull codes form the ecu, also do a boost leak test i made something at home depot for like 8$.

i had the stumble at 5psi and it was form the knock sensor rewired it and bam no stumbling and nice smooth driveability below 3500.

[zmannz]

maf, knock sensor, 02 sensor, tps last resort

[jynxtrix]

(*&)(*! I forgot to wire my knock sensor! I'll get on that first thing after work! damn I can't believe I forgot that!

[zmannz]

Hey I spent 4 days tuning my car to overcome a bad knock sensor lol....

[jynxtrix]

hooked up knock sensor. no codes, same problem.

[float_6969]

Is it a heated O2 sensor? If not, the output of the O2 sensor isn't correct at idle due to lack of temperature of the exhaust at idle.

[jynxtrix]

so does that mean the lean reading is wrong? it's not heated. and it goes red when I let off the gas, normal I'm sure with the fuel cut, but it starts to do it again after 5 psi. I wish I had someone with experience around here.could the fact i have a stock fuel pump, or maybe a stock FPR have any effect on this? it also keeps wanting to run hot, never in the red, but pretty damn high none the less.
Modified by jynxtrix at 9:58 AM 7/25/2009

[zmannz]

Sounds to me like your ecu is getting either a varied signal from maf or tps, or your ecu is not reading afr corectly. Do you have a thermometer to check egts? If you can't get an exact afr, try driving the car hard a few minutes, let it stumble how it will, then hop out and shoot your turbo/downpipe with the thermometer. If its over like 900 on a 4 cylinder, you might be way lean, maybe even at lower temps than that. This only applies to a nearly stock motor, more horsepower increases average egt usually. If the temps stay low, you are rich.

[float_6969]

Wait, it goes lean over 5psi as well? Something isn't right.

It is possible for the FPR or fuel pump to cause these problems. The only way to verify would be to hook up a fuel pressure gauge and drive the car.

[jynxtrix]

yeah, slightly lean aft 5 or 6 psi.quick question, pulled my turbo off and there's a puddle of in the intake side of it. so i've decided to rebuild it, but how the hell do i know hat kit to get (i hate ebay, but it's my best bet for parts around here) so that being said, do i just tear it apart and figure it out from there or what?