IAC Testing

craig1701 · #1 (**permalink**) 08-28-2010, 04:52 PM

I would like to know how I can test the IAC motor I have been having issues with the engine idling and saw a post by Donsbolt about his IAC motor sticking and that is what i found wrong with my IAC motor. I pulled the IAC off the back of the EZ-EFI and the plunger was stuck . I had to pull on the plunger to get it to move it was definitely stuck.
It moves freely now in and out which it did not do before The reason i would like to test the IAC is i am in the process of changing the cam right now and do not want to wipe off the breakin lube on the cam if i have problems with the IAC not working.
I did hook up the IAC motor to the wiring harness and looked at the Live Data display and it showed 90, I moved the plunger in and out and the display never changed from 90.
Thanks

craig1701 · #2 (**permalink**) 08-28-2010, 05:34 PM

I found a post on here and it said that i should have 50 ohm between a pair of pins on the IAC motor
Do I have a bad IAC?
I checked my IAC motor and it shows 48.8 ohm on one pairs of pins and 48.9 ohms on the other pair of pins.

David_H · #3 (**permalink**) 08-29-2010, 02:26 AM

I would think your close enough in the ohm range. but you mentioned it was stuck right did you free it up? what was it stuck on?

craig1701 · #4 (**permalink**) 08-29-2010, 01:53 PM

Yes it was stuck
It was stuck internally. I think it was a defect in the Manufacturing process
I just pulled out on the plunger really hard and now it moves in and out with out the plunger sticking
Does the plunger only move in and out when the engine is running ?

David_H · #5 (**permalink**) 08-29-2010, 04:48 PM

The thing is was it stuck or did you break it by freeing it up?
I never took one off so I don't know you will have to wait for one of the tech guys to chime in on this one...

craig1701 · #6 (**permalink**) 08-29-2010, 09:52 PM

I dont think the IAC is broke
I just wanted to post on here that I noticed that it was stuck like Donsbolt had in his post
EZ-EFI allmost there, but a fer little issues, look at my readings
Thought this might be an issue that other people might like to check if thay are having problems with there engine not idling right.
Hopefully FAST knows of this issue.

FAST Tech Maxwell · #7 (**permalink**) 08-30-2010, 12:56 PM

The spec for ohms on that IAC valve is ~56. I am not sure what temperature that spec is given at, so I think your measurements of about 49ohms is about right.

Main things you are looking for there are no continuity, which would make Ohms out of limits, or some type of short in the coil, which would make Ohms very low like less than 20.

With the key on engine off, the IAC will not move. The ecu commands only 1 position, and does not change it.

Once you start the engine, you should see the IAC pintle move in or out. You might try and tape up the holes on the throttle body and start the engine with the IAC out, so you can see it. I believe that's what Donsbolt did.