Running Lean, need help!

[SRraider]

To give you a little backgroud info here, I have a 92 s13 hatch w/ a redtop sr swap and 5 speed conversion. I have the stock sr maf, 300 zx fuel filter and walbro 255lph fuel pump. Well I've been having idle problems for a while now. Car would run fine when I started it up cold, but if i started it up after it was already warm, it would sputter at idle, dropping to 400-700 rpms. Well today I installed my AEM air/fuel gauge and wideband 02 sensor. When i start my car up (after its warmed up) it idles low still and my afr is off the gauge, well above 18 afr! When I drive it, under boost it drops down around 12-14. Any ideas guys?

[compression]

you are definitely well above a healthy idleing AFR. Mine idles great right around 15:1 AFR.Check your vacuum line to the fuel pressure regulator, also make sure your fuel lines (feed and return) are hooked up correctly and you have the correct injectors installed. thats all i can think of right now.

[Blown240sx]

15-16 AFR for idleunder boost you want around 12.2 or lower for safe but the stock ECU trys to keep it around 14.7 which is stoch.

[SRPWR]

Dont you have another Maf? SOHC? Try that.

[SRPWR]

Gonna bump this for ya bro.

[SRraider]

Well I had a spare SOHC maf sitting around so today I wired it up, but it runs exactly the same. I start it up, and the afr sits at about 15-15.5 then after about 30 seconds it raises to over 18 and off the gauge. Another thing that concerns me is that I had a friend mess with my car trying to fix the idle and he realized that when he unplugged the idle air control valve (that thing in middle of the intake manifold) that it didn't effect me car at all. They told me that my car should die when they unplugged it, but it didn't. I'm not nessissarily saying that thats the problem though. What evers effecting my afr might be causing both problems. So again, anyone have any other ideas?

[Blown240sx]

yes it should die unless your throttle body is stuck open some. Try replacing that it might be stuck open to far.

[240sxdominos]

Any chance it could be the TPS (throttle position sensor) my idle was messed up and a buddy of mine fiddled around with that and it seemed to fix the problem.

[SRraider]

Any chance it could be the TPS (throttle position sensor) my idle was messed up and a buddy of mine fiddled around with that and it seemed to fix the problem.

I'm not sure. I seem to remember checking it and getting full voltage, but I'm not sure. I can check it out. Does anyone know what kind of voltage I should be getting? Also, it might be my coolant temp sensor. Is that the sensor behind the TPS?
Modified by SRraider at 9:34 AM 12/6/2006

[SRraider]

So ok, at lunch I got my car warmed up. I shut it off and when I restarted it, it started sputtering and running over 18afr. I unplugged the coolant temp sensor and the idle climber back up to about 1200 rpms and the afr when back down to between 14-15. I also tried unpluging the IACV but nothing happened, but if i adjust the screw on top it still alters the idle. Would it do that if the IACV wasn't working?

[Blown240sx]

Yes since the screw just allows more air to flow through. IACV holds the idle at a certian RPM and air flow.

[xero1]

my afr is 13.3 at 850 rpm(idle) is this normal?

[Blown240sx]

no thats very rich. We were tuning my buddies can and anything below 2500 hes running 14.7 AFR or higher. 16-17 AFR at idle.