My IAC pig tail was soo badly dry rotted that it finally crumbled last time i removed it. I was left with 4 bare metal pins.

I pickedup a replacement from a store online, but I dont know which wire is matched to which pin?

Anyone got a diagram for this?

I have green/white green/black, blue/black and blue/white..

 

So I finally found the required info.. am posting here for posterity..

pin A blue/black
pin B blue/white
pin C green/white
pin D green/black

With the ALDL pins A&B shorted with a paper clip (top row far right), you should read 5.5V on each pin with a volt meter, that is with the ground on the battery/body and the red probe on each pin. Just put the ignition on, don't start the car.

Next remove the IAC motor and test it..

Remove the motor with a large wrench, clip the pigtail back on, wrap the motor in a cloth. Short pins A&B again, then turn the ignition on, don't start the car. The IAC pin should rotate out, along with the spring, if you didn't use a cloth its on the other side of the garage..if it doesn't come out give it a rotate and try to free it up. Once it comes out, lube with a drop of grease and reassemble screwing the pin and compressing the spring all the way home into the IAC Motor.

Re-insert the motor and set..

Re install the IAC valve/motor, and reconnect the pigtail. With the paper clip still in the ALDL connector, turn the ignition on, this will push the IAC pin out into the throttle body, wait 30 secs. Turn the ignition off, remove the paper clip from the ALDL connector.

Set the IAC start position by removing the pig tail then starting the motor, the engine will idle at about 1000-1200rpm, wait for 20 secs. Shutdown.

Reconnect the pigtail to the IAC, start the car. Expect it to idle at about 550-650rpm, depending on engine temp.

If idle is much higher check for leaks in vacuum lines, to the throttle body, there's one on the pax side, and below front driver side, and the vacuum tree coming from the MAP sensor at the rear of the plenum. check for leaks in the intake and plenum gaskets, at the vacuum canister and cruise control. Spray carb cleaner liberally, and look for a drop in engine RPM. Fix if found..

This worked for me and gives me a really nice rock steady low idle, and fixed the problem of the car intermittently dyeing at stop signs..

 

im having some idle issues but i believe its because of my speed sensor im in the middle of fixing that but a couple of guys said to check my IAC well mines drywrotted aswell it still works but my question is why do you prep the system like that by shorting the system out?

 

Because it proves that the iac motor is working properly, and when you reinstall it it sets the pintle to the correct position.

Honestly I'd be surprised if your idle problems were related to the vss, after checking timing, plugs, rotor and cap, wires, I'd check the iac motor, make sure it's clean use a can of carb cleaner in the passage between the throttle blades, then check the throttle position sensor.

My iroc idles at a rock solid 550rpm when warmed, so happy with it!

 

yeah i agree with you on being doubtful about the VSS but the car ran perfect tranny went wout and i swapped a junk yard tranny in and couldnt hook up the VSS and now my car has stalling problems at idle but i got it in the garage right now figured out how to put my stock VSS back on so im doing that and i'll have one of my guys clean my IAC definitely appreciate the post though and i would love a 550rpm idle that would be great lol