High Idle 90 Corisca 2.2


YJKing95
10-19-2007, 10:05 AM
I got a 90 corsica w/ a 2.2 and it came in w/ a high idle around 1700 rpm all the time, IAC was not responding and no working the way it suppose to. replaced the IAC and motor still does same thing.
Scanner indicated that the IAC counts were around 140 and it normall should be around 30-50 at max, PCM voltage on the scanner incated that it was 4.5 to 7.3 volts, alternator is charging and working proprley.
I checked power and gorund at IAC and TPS and my multimeter showed that i was getting 12volts to the sensor, but from what i recall i am supposed to be getting a 5v refrence to the sensors and not battervolate?

anyone have any ideas? possibly a PCM? im stumped over here, any kind of help would be great.

jsgold
10-21-2007, 11:36 PM
Only things I could think of would be a massive vacuum leak, a bad TPS, or a CPU going bad. Your scanner should be able to show the percentage you throttle is opening / closing. Corsicas are known for CPU failure due to moisture, ours went out 5-6 years ago. It was giving false codes though, not running issues. My son had a 89 Beretta with same engine with a bad vacuum leak that caused a very high idle. When fixed it was OK. Maybe a leaking intake but I doubt that. Have you checked for error codes stored??

YJKing95
10-23-2007, 09:22 AM
Only things I could think of would be a massive vacuum leak, a bad TPS, or a CPU going bad. Your scanner should be able to show the percentage you throttle is opening / closing. Corsicas are known for CPU failure due to moisture, ours went out 5-6 years ago. It was giving false codes though, not running issues. My son had a 89 Beretta with same engine with a bad vacuum leak that caused a very high idle. When fixed it was OK. Maybe a leaking intake but I doubt that. Have you checked for error codes stored??

Yeah i finally figured it out, the throttle % was at zero with the throttle closed and it was in specs, the Battery volatege on the scanner said 5- 7 volts was very odd, had no vacuum leaks and the o2 sensor was flutuating like normal witch elimantes a vacuum leak , so i put in a new PCM and if ran fine!!! thanks for the tips.

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