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Try again --- the computer took control of my keyboard
The IAC, idle control valve, is a permanent magnet "motor", or Valve. The internal shaft of the motor\valve is connected to the actual valve and the valve turns clockwise and counterclockwise depending on which contact of the connector get the + voltage from the Computer(and not neccessaryily the full +12 volts, or if it is full 12 volts it is only pulsed and not full on). The middle pin of the connector is ground. You can test this booger by connecting +12V to one of the end pins and the shaft will turn to full one end and against the stop(full open).Then put the +12V to the other end pin in the connector and the shaft will turn to the other end stop(full closed). The middle\center pin is ground.
This little booger works like a "flutter valve" and the ECU sends + voltage to whichever connector pin needs to be energized so that the air control valve, IAC, moves more open or more closed depending on whether it need to increase or decrease the idle speed.
You can bypass this dratted valve by disconnecting the connector and plugging up the hose with a broom handle (or other type plug), and then you can brute force set the idle with the "black knob" on the throttle body. This is not so elegant as the auto system, but it surely works and will get you home and prevent stalling at all stop lights(or idle "run away").
It is probable that the IAC is just stuffed up with crud. Give it a generous bath with WD 40 (shoot it full right into the hose from the throttle body) and that might loosen it up so that it will rotate easily and then work as it should. It might take more than one douch to do the trick. If yoiu have it out in your hand, you can douch it and reach in and turn the shaft by hand to ensure easy movement. That's what I finally did to mine. I also took mine apart to get a good look at the innards to ensure that I know how it worked (or didn't work).
They are contrary for sure Good luck
bob rjstulsa@aol.com
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