idle surge

I have a 1982SC and I have serious idle surge at start up and after the car is warm. I've replace the fuel regulator, cold start valve, plug wires, fuel injector seals, and still the same surging problem. Any ideas Thanks

Check the aux. air reg. The fuel pressure reg. and the aux. air reg. are timed together so that the air by-passing the throttle plate is calibrated to the fuel enrichment. If the aux. air reg. is sticking, your engine won't have proper fuel/air ratio during or after warm-up. Also check the throttle micro switch. It's the one on the right side of the throttle housing with two wires connected to it. This switch should be closed at idle. The idle switch modifies the time the frequency valve cycles on and off, and this could also cause an engine surge.

Good Luck,
Lee

Sounds like you need to get your idle CO adjusted.

Joe

My dad has an 80SC with the same problem for four years. He had the engine rebuilt, the car runs great, except the idle hunted around 800 to 2k when it was warming up. He replaced the warm-up regulator three times. Each time was with a "known good unit". Somewhere there is a article about drilling out the adjustment screw on these and making it adjustable. He then replaced it a fourth time. The idle was better, a little off (not 2k rpms). He was told to have the sensor plate checked for center within the manifold. Please forgive my non-technical names.

Either way good luck
Nick
'85 Carrera

I think your problem may be in adjusting your airflow sensor plate. I had the same problem with my 78 911 Sc. It would surge from 850 to 1500 rpm. Check it with the engine off and see what position it is in. You need to get the specs on it for your particular setup. Start the engine and if the problem still persists, adjusted the screw under the sensor plate - raise it a little at a time and see if that doesn't solve the problem.

Steve

Do you have a success report based on the advice given? Something else? I've been experiencing the same thing and been unable to isolate the problem.

I had the same problem and replaced fuel pump check valve, fuel accumulator and Warm Up Regulator. The Idle hunt was still there. I took it to my mechanic and all he did was check the fuel pressure and adjust accordingly.

Hmmm... Spent the weekend isolating the components hung on the front (in driving direction) side of the engine, using handiwrap to block airflows. Idle hunting still there, but magnitude greatly reduced. Will thoroughly check the WUR this weekend.

In the process, finally solved the extended high idle speed when cold. "Drive in the plug" in the aux air regulator similar to the technique used to adjust the WUR.

[This message has been edited by Brian K. Haggard (edited 01-03-2000).]