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Weird IAC problem update, any ideas ? 700 1985

posted by  john sargent on  Sat May 1 06:07 CST 2004
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last visit: Wed Oct 22 09:07 CST 2014
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The IAC on your car is a three wire connection where the center wire is powered via the fuel system relay and the outer two terminals are alternately grounded for varying duration by the ECU. One terminal when grounded closes the IAC, the other terminal opens the IAC. One of the outer wires is always grounded, and thd duty cycle is continuous. If one wire is grounded 42% of the time, the other wire will be grounded 58% of the time.

Unplugging the IAC (with engine running) usually doesn't change idle speed as the IAC will usually stay where it was when unplugged and stay in that postition, giving you an idle speed between 700 and 2000 RPM.

I would check and set the Throttle Position Switch. The IAC will not be operated in idle mode by the ECU unless the Throttle Switch is closed.
--
john






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New Weird IAC problem update, any ideas ? [700][1985]
posted by  rduke  on Sat May 1 05:23 CST 2004 >


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