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Replacing IAC valve in 1992 Mercury Tracer

I have a new IAC valve for this car and want to know exactly how to proceed with the replacement. The car has a 1.9L engine.

The valve is meant to solve a problem with rough idle when the engine is cold. The AC causes the car to stall out at any time when I'm idling.

The valve looks simple enough to replace. However, the guy at the auto parts store told me to disconnect the battery when I make the replacement. Why is this necessary? More important, do I just disconnect the battery, replace the valve and then hook the battery back up?

Second, the valve has a black knob on the side. What is this knob for?

Finally, do I need to make specific adjustments in the idle speed? I just wonder if I'm going to need an RPM guage.

Thanks.

Reply to
Bob Jones
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just unbolt the old one (probably 2 bolts, maybe 8mm, on the intake manifold) and unhook the sensor. bolt the new one on and attach the sensor, and the iac is good to go.

the reason you are supposed to disconnect the battery is to clear the KAM (keep-alive memory). the car's computer "learns" information to optimize the fuel/emissions system where it's supposed to be, and when you replace a part that "taught" the computer bad info, you want the computer to be able to learn based on a fully-functioning part. the battery needs to be disconnected for at least a few minutes (or you can optionally just touch the two terminals together somewhere away from the battery).

ignore the little knob on the part, just assume it works, and don't touch your idle speed.

john

Reply to
John T. Waisanen

John:

I couldn't have asked for a more clear and concise answer. I easily installed the new IAC valve, and the Tracer is running great.

Bob

Reply to
Bob Jones

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