IAC Motor Test

Dirtbuster1

Well-known member
Joined
May 13, 2008
Messages
649
Location
Georgia
Is there a way to test my IAC motors. I have driven about 20 miles now & they still have not reset. Is there a way to ohm them out. If I took them out when starting should they respond.

The car is still not idling up when cold. If you try and drive it cold, it is very sluggish & tries to stall.I don't want to buy new motors at 70.00 a piece & find out there is another problem.
 
Is there a way to test my IAC motors. I have driven about 20 miles now & they still have not reset. Is there a way to ohm them out. If I took them out when starting should they respond.

The car is still not idling up when cold. If you try and drive it cold, it is very sluggish & tries to stall.I don't want to buy new motors at 70.00 a piece & find out there is another problem.

They have 4 pins?? if so, two have some continuity, the other two will have damn close, and there is NO conduction betewen the pairs....

the IACs I have on my L98 t body are similar, I suspect....screw in jobs abut 1.5 inches diameter and like a 1/2 NPT thread size....unscrew the things are clean them with carb cleaner, then blow them out, and a small dep of silicone spray....spray out the tbody IAC passages.....clean the tbody around the airvalve....black gunk buildup.....

put it all together and do the IAC set proceedure.....

hope that helps...

:smash::twitch:
 
they are STEPPER motors!!!!!!!!!!!!! You can NOT just test them like that.
 
Update,

I took the motors out today and checked them out. Both ohm 57 ohms on both sides of the motors. Put ECM in diagnostic mode, and they both move in & out about 1/8" inch. I reset them to 15/16" and reinstalled. changed ECM again for the hell of it, & the front IAC didn't move. The Rear IAC moved all the way in and stopped. The motor wasn't running even. Took them back out and remeasured gap. Same result.

If I screw them in & out by hand, one of them works ok, the other shaft does not want to go in unless I put alot of pressure on it. I unscrewed the shafts again, & put on some loctite. Don't know if this will help, but what the hell. Called O'Reillys and I have 2 coming tommorow if I need them. 70 bucks a peice.

Any suggestions
 
they are STEPPER motors!!!!!!!!!!!!! You can NOT just test them like that.


I"m checking just continuity.....I know they are steppers...

just covering a base....I have never had one fail completely and cleaning has allways fixed the sluggish behavior....tbody need be clean in and out, the passages, and the blades...holes....carb cleaner and a air jet does it right in place....I suspect same for the cross fire....

:thumbs:
 
I've never had one fail either, well..they do fail if people try to move the pintle themselves. It's just a std. GM delco stepper motor.
 
I've never had one fail either, well..they do fail if people try to move the pintle themselves. It's just a std. GM delco stepper motor.

STANDARD?? no such thing from what I seen...they have some 3 differant pintle heads.....and of course differant passages, and then we get down to these things are no longer screw in but some plastic bolt on

getting to like bending sheetmetal anymore....

Mass production my ass.....

a box is a box is a box allready....fine one that works well, produce IT, and fix the problems with the existing BOX, not reinvent the wheel....

ah nevermind, I in a pissy mood, fucking idiots of the world.....

lousey day at work with much adoo over nothing....

:clobbered:
 
I've never had one fail either, well..they do fail if people try to move the pintle themselves. It's just a std. GM delco stepper motor.

TT,

Could you explain to me about moving or damaging the pintle. Is it normal to be able to unscrew the shaft. I am assuming since there are 2 coils that flux moves the shaft in & out.

Any suggestions would be great.
 
Does the stud thread into the motor, or is the stud supposed to screw in & out for some other reason?
 
Just read an article that I found.

Clarify this for me. Do you push the shaft in & out, or screw it in & out. This might be what I am not understanding.

I will attach the file. The files to big to attach?
 
Just read an article that I found.

Clarify this for me. Do you push the shaft in & out, or screw it in & out. This might be what I am not understanding.

I will attach the file. The files to big to attach?


Excerpt taken from the url I referenced above.

The pintle valve is on a worm gear, rotation of the stepper motor moves it in and out. The coils take turns to rotate the pintle by 90º. At any time, one coil is 'enabled' and can rotate the pintle in either direction, the other coil is in a neutral position (will not cause the pintle to rotate). Applying a voltage to Coil A will turn the pintle 90º in one direction. (The opposite polarity (on coil A) will turn it in the opposite direction.) Applying a voltage to coil B will rotate the stepper motor in the opposite direction by 90º, or back to the original position.

A worm gear would imply that the shaft screws in or out. Did I understand you correctly?? You didn't loctite the worm gear did you?

Bullshark
 
Bullshark,

If the worm gear is the shaft that screws in the motor with the pintle on the end of it, yes.:smash::smash: I was thinking that the shaft would move in and out by the coil flux. Why would there be threads on the shaft other than connecting it.

:bomb: I'm about fed up with this Damn Crossfire.:bomb::suicide:

Any body got a match? I took it for another ride. The motors did not reset, and I almost didn't make it back home. I got a code 44 when pulling up to my house. That's probably why it felt like it was running out of fuel. It took very little throttle, or it would try and shut down.

Help
 
:bomb: I'm about fed up with this Damn Crossfire.:bomb::suicide:

Any body got a match?

Been there, done that. Time to take a break and let it sit awhile. I have almost burned mine numorous times. 81-82 ECM controls are rudamentary at best, and can drive you nuts.:suicide:
 
I just replaced the 2 IAC motors. As I suspected they did not help. Yes they will move in & out in the diagnostic mode, but it seem that when the car gets hotter they don't readjust themselves. I seems like when the car gets hot, it's starving for gas. But with the IAC motors fully open that would happen.

I'm going to make up a gauge to check fuel pressure to eliminate that. It just runs to good cold to confirm that is the problem. Is it possible for a CFI to Vapor Lock? If the car was running in open loop, would that throw a code?

I also have ordered an ALDL cable for Win ALDL to see what's going on.
 
I also have ordered an ALDL cable for Win ALDL to see what's going on.

Good idea, it's hard to shoot from the hip in the dark:D I doubt vapor lock is the culprit. Starting to shape up like a heat sensitive intermittent. Maybe a bad connection or bad circuit in the ECU. More data needed.

Bullshark
 
I have 3 ECM's. Maybe I will try the 3rd. It's probably something simple, but it's getting very costly.
 
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