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High Idle 98 OBW


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#1 hankosolder2

hankosolder2

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Posted 05 November 2007 - 06:51 PM

Greetings All--

My '98 Legacy OBW 5MT has a high idle 1100-1500 rpm when hot. I think the problem began after the car sat for a week.

I don't think it's the CTS as the fans cycle normally when the engine is warmed up- so the computer knows the engine is up to full operating temp.

I did a cusory check for vacuum leaks. I suspect a sticking idle air control valve. Attempted cleaning of the IAC didn't do it. I'll track down the problem, but I have a question-

I know that the ECU is programmed to cut fuel to one cylinder & set the CEL when the idle RPM exceeds a particular number. (I read this somewhere and experienced it first hand a while back with a stuck open IAC on an engine which had sat for a year.) Does anyone know what the magic RPM number is?

Nathan

#2 porcupine73

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Posted 05 November 2007 - 08:24 PM

I know that the ECU is programmed to cut fuel to one cylinder & set the CEL when the idle RPM exceeds a particular number. (I read this somewhere and experienced it first hand a while back with a stuck open IAC on an engine which had sat for a year.) Does anyone know what the magic RPM number is?

Sorry I don't know the magic number but I know there is a note on endwrench.com about exactly what you mentioned.

#3 hankosolder2

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Posted 05 November 2007 - 11:46 PM

Sorry I don't know the magic number but I know there is a note on endwrench.com about exactly what you mentioned.


I found the endwrench note and it doesn't give a specific RPM; it just states that then the ECU determines it has lost control of the IAC, it kills the injector pulse to one cylinder at idle.


Nathan




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