Hey guys. I pulled my IAC out and checked to make sure it was working by plugging it into the harness again and turning the key on while the diagnostic A&B ports are jumpered. But being an idiot, I did not have the motor in the housing and the shaft and spring zoomed right out as soon as I turned the key. I tried putting 12 volts to the connector in a few different configurations to try to reverse the motor and pull the shaft back in correctly, but it won't move. Which terminals do I put voltage to so I can fix my little mishap and drive the car?

Thanks,
Adam

 

The IAC being a stepper motor, best bet it to use the ECM in the same manner as before. Only this time reverse two of the leads. With some jumper clips connect the connector to the IAC while switching the 2 green leads. That should work. If not, also switch the 2 blue leads. One of those two wiring setups will cause the stepper to run in the opposite direction.

Just be careful to not short the leads together.

RBob.

 

Ok I figured it out! When you turn the engine over with the throttle closed the IAC opens completely to allow air past, so I hooked it up and plugged the holes in the throttle body. When I turned the car over the motor reversed and pulled the plunger back in. SOLVED!! Thanks for the help though.

-Adam

 

You could have simply assembled it by hand, but it DID make a nice story.

 

Assembling it by hand wasn't really an option considering the design of the shaft. The bottom half of the shaft is threaded to match the inner sleeve of the motor, and the upper half is smooth with a keyway in it in order to prevent the shaft from spinning when the motor turns. In order to fully thread in the IAC motor, that shaft has to be threaded in past the point where the keyway stops it from turning, so the only way to get the shaft far enough in is to use the motor to pull it back in. Thus my problem. You're right though, it DID make for a good story. I got a few laughs from freinds as well.

 

It isn't really threaded. If you examine it closely, you'll see those "threads" are actually complete rings, not a continuous thread. The pintle and spring are positioned, the two flats on the pintls shaft are aligned with the keys in the stepper motor nose, then the pintle can be rocked back and forth while being pushed gently inward. The rocking alternately engages the opposite rack gears in the stepper motor, allowing the pintle to "walk" into the gears and IAC housing. It takes about 5-6 minutes to work a pintle in all the way. Your way is faster, but depends upon the IAC being commanded to step in the proper direction when the ECM is powered up.

 

Touche Vader, Touche. Good to know. Prior to my little mishap I had no idea what a stepper motor even was. In all honesty I was very lucky I didn't break the motor or pintle in my tinkering to figure out a way to fix it. I had no idea that was how the inner workings were. Well lesson learned and again thanks for your help. The car still has issues however with a stumble at higher rpm's, but I'll have to post another topic to get that straightened out.