Idle Parameters (EFI)

[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

[dean]

My idle is right at 1000 rpm, my timing is about 12 degs and injectors at 1.82ms. My air fuel is right at 14 idleing.

[beepbeep]

Well, if you like your idle character then keep it. But you can also go Dean's route and lean out the idle/pull down the timing. It will use slightly less fuel and give better emissions.

Lower timing at idle will also give you slightly lazier throttle response when you prod the accellerator in neutral but I would still lean it out, if nothing else then just to keep emission guys happy. As long as you keep rest of map untouched your engine character would remain the same.

To bring it into contect: max CO for 930 79' in Sweden is 4.5% at idle. It's the only emission parameter they look for for car of that age. Running att AFR 11.8, you car would probably not pass Swedish emission check. But if you leaned out the idle to 14.0 or so, it probably would. Everything else would remain unchanged.

So I guess it boils down to your preferences, local emission laws and fuel efficiency issues.

[David]

1050 rpm, 14.2 AFR, 15.5°, and I still haven't set it up to log injection times.

I don't have an idle air valve and it really looks like I need one or something. It takes a couple minutes of assisted idling before it'll idle on it's own.

Now I have a new problem. Sometimes it won't start hot. I haven't really given it much thought, so I'm open to suggestions.

[Rory Mckenna]

What rpm should a stock US spec 1979 930 idle at?

[DonE]

Originally Posted by dean

My idle is right at 1000 rpm, my timing is about 12 degs and injectors at 1.82ms. My air fuel is right at 14 idleing.

Thanks guys.

When I received the base map, it had 20 degrees, and worked. When I started tuning it, I worked my way down a degree at a time. Around 15 degrees, it didn't want to idle at all, so I went back up. So, I tried 6 degrees and ended with 8 degrees, 14 AFR and 950 rpm with a stable idle.

Thanks again.

[Porschephd]

Don,

I run about 13.8-14 AFR and about 10-12 degrees. Keep in mind that different injectors may not idle with a high AFR like that. There are a lot of variances with injectors and two different sets may not idle the same.

[DonE]

My injector time jumped up to 1.80ms, raised the AFR and lowered the RPM. The injectors are mototron 60lb.

[930gt-40r]

1100 rpm- 17 degrees, 12:1 afr