DonE

I would like to compare my idle parameters with others who have EFI. For example, my car idles at 1050rpm, 22 degrees timing, 1.68ms on the injectors and 11.8 AFR. The idle is dead on, recovers after any throttle position, good oil pressure (the reason I set it to 1050) and immediate throttle response transitioning to acceleration.

The AFR would say its rich, but even the plugs are relatively clean after an extended idle (4 or 5 min). I'm just interested in what anyone else is running. Thx

Geoffrey

My experience suggests that your idle is unnecessarily rich. I set the cars to run at about 900rpm warm, and as lean as possible which varies with injector brand (quality) and camshafts, but is in the 13.8-14.2:1 range. If you do not have an idle air control valve, a 900rpm warm idle will generally not allow for a cold idle on a cold start until about 30 seconds after the car has started.

I think that if you did oil analysis on your engine oil, you will find that there will be an abnormally high fuel content in your oil which is not a good thing.

DonE

But it does not want to idle at anything leaner or lower (rpm). It hunts and is rough. ??

Geoffrey

I've never not been able to tune a 911 turbo engine as I described above. Your ignition timing values are much higher than I use which may be a contributing factor to your idle issues.

fast951

DonE, you have a PM.

turbobrat930

Well Don, since you asked...... My idle depends on how fast I can move my two legs.... and my AFR depends on wether or not I had Mexican last night!!!!!! HAHAHAHAAAHAHA

DonE

Funny Brad - go eat a doughnut.

When tuning the idle, I started at 20 degrees (because thats the base file I got and it seemed to work) and tried working my way down a degree at a time. When I got to about 15 degrees, it didn't want to idle at all. So I stopped, and went back up. Today, I set the timing at 6 degrees at got a stable idle at 8 degrees, 14 AFR at 950 RPM.

Thanks gents.

Geoffrey

Exactly! I generally have about 5 degrees of ignition timing at idle.