PDA

View Full Version : Lean at Idle

Pages : [1] 2
sleepydsm
10-03-2008, 12:15 AM
My AEM o2 says normaly "---" which is max lean at idle, sometimes its between 18:1 and like 15:1. While cruising, the car sits at like 14.7 as it should.

Any ideas?
95talonracer
10-03-2008, 10:41 AM
Mine does the same thing. Where is your sensor placed in your exhaust system? How far down? Mine is where the second o2 us and I am thinking of moving it up farther but you dont think that should matter since when they dyno a car its at the very back tailpipe.
4g63tcrazy
10-03-2008, 11:15 AM
Wouldn't it make sense to have the car idle lean? Cars usually dont use up that much fuel just idling.
sleepydsm
10-03-2008, 12:35 PM
I thought it'd be at 14.7...

My sensor is 36" away from the turbo outlet, per the AEM instructions, which on my 1g places it just behind the axel and between the crossmember. Perfect :)
dsm9sec
10-03-2008, 12:46 PM
I thought it'd be at 14.7...

My sensor is 36" away from the turbo outlet, per the AEM instructions, which on my 1g places it just behind the axel and between the crossmember. Perfect :)

Have you gotten your car tuned prior to installing the WB?

Better yet, are you on a stock ECU?
sleepydsm
10-03-2008, 12:49 PM
yeah, stock ecu, pretty much stock everything else. Has a stock set zero'd out MAFT and stock 450s. Aeromotive AFPR and walbro 255hp. stock 14b also. stock 6 bolt kinda.
dsm9sec
10-03-2008, 12:51 PM
yeah, stock ecu, pretty much stock everything else. Has a stock set zero'd out MAFT and stock 450s. Aeromotive AFPR and walbro 255hp. stock 14b also. stock 6 bolt kinda.

Then I probably wouldn't worry about it. The stock ECU adjusts fuel trims as it sees necessary.
Goat Blower
10-03-2008, 01:19 PM
Mine does the same thing, and it's not right. In closed loop, your a/f should hover around 14.7, that's where it's supposed to be. Mine goes lean and the idle drops to 900rpm and it stumbles. I haven't had time to mess with it, it might be the removed honeycombs on my maf, I'll find out soon enough.
JET
10-03-2008, 01:49 PM
Sleepy, it sounds like your WB is probably getting too cold and not giving a reading any more. Mine used to do that at idle sometimes too. I was actually too rich causing the sensor too cool too much at idle. I can really see the problem with it being that far away from the engine, that is a long ways away.
dsm9sec
10-03-2008, 02:08 PM
My WB is right where it sounds like Kevin put his. 1" behind the half shaft @ the center of the motor and mine didn't cool. I thought they were self-heated?

One thing I do know for sure is DO NOT put it right where the turbo outlet is if it's a street car. Mine burned up in 2 months @ that spot.