Cleaning and Resetting Your Idle Air Control (IAC) Valve


(How to shown on 350 TPI engine)What you will need for the following procedure is carburetor cleaner and a wrench big enough to remove the IAC valve. Ensure your ignition if OFF.  Remove the connector to the IAC valve, located right below the Throttle Position Sensor (TPS) on the left side of the throttle body as you are looking at it from the front of the car.  You may find it necessary to remove the air intake snorkel assembly (don’t forget the MAF connector if equipped) as well as the breather and surrounding vacuum lines to the throttle body, to gain better access to the IAC valve.

Using a wrench, remove the IAC valve by turning it counter-clockwise (loosen) and remove the valve.  Spray it down with carburetor cleaner until it’s clean and then proceed to spray some WD-40 on it for that little added protection.  You can use a soft brush (like a toothbrush) to help with the cleaning.  Generally, carburetor cleaner adds enough coating to the valve, so WD-40 may be a little overkill. Before reinstalling the IAC valve, measure the distance that the valve is extended, from the motor housing to the end of the cone.  It should not exceed 1-1/8" (28.6mm), or damage to the valve may occur when reinstalled.  You should use a new gasket when possible.  If the valve exceeds the specified measurement, press firmly on the valve to retract it. Reinstall the IAC valve, reconnect the IAC connector and reassemble all components removed to gain access to the IAC valve (air intake snorkel assembly, hoses, vacuum lines, etc.).  If you removed the air intake, ensure you reconnect the MAF sensor (if equipped). Turn the ignition ON and leave on for several seconds then turn the ignition OFF to allow the ECM to reset the IAC valve. You should be good to go.  If you need to adjust your minimum air (idle speed), click here.  Any adjustments made to the idle speed, should be followed by adjusting your throttle position sensor (TPS). I will try to follow up with some additional images in the days to come. -  Allan -Allan Reinike

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3 Responses to “Cleaning and Resetting Your Idle Air Control (IAC) Valve”

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