mr.radon Posted February 10, 2009 Share Posted February 10, 2009 1989 GL SW, SPFI. I have to control idle with a vice grip on the rubber hose going to the idle control valve. I know the solenoid is good, valve is clean and works fine, what else do I check. It runs fine, but without the clamp on the idle air bypass hose it runs at 2200RPM. Been doing that for a few months now. Hum, right after emission check, was right at 775RPM. Oh, if I unplug the connector to the solenoid idle drops to 560 (warm engine only). Help please! Quote Link to comment Share on other sites More sharing options...
92loyale Posted February 10, 2009 Share Posted February 10, 2009 Check all your vacuum lines! That's where I would start. Quote Link to comment Share on other sites More sharing options...
torxxx Posted February 10, 2009 Share Posted February 10, 2009 You have a major vacumn Leak some where and the engine is trying to compensate for the leak EGR valve could be sticking, or the solenoid isnt functioning, holding the solenoid open. Quote Link to comment Share on other sites More sharing options...
mr.radon Posted February 11, 2009 Author Share Posted February 11, 2009 Anyone have a link to a Subaru Shop Manual vacuum diagram? I know the solenoid is good, the signal is coming from the ECU for some reason. If I hook up a PWM pot to the solenoid I can control the idle RPM just fine. Quote Link to comment Share on other sites More sharing options...
ihscout54 Posted February 11, 2009 Share Posted February 11, 2009 Check your coolant temp sensor and connection. There is probably nothing wrong with the IAC valve, its being told to stay open. Quote Link to comment Share on other sites More sharing options...
XT6 Magic Posted February 11, 2009 Share Posted February 11, 2009 Agreed. If it had a vacuum leak unplugging the valve would not lower the idle speed, correct? Quote Link to comment Share on other sites More sharing options...
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