Car stalls when place in gear with A/C on. What should the IAC counts be?

GNVAIR

Member
Joined
May 24, 2001
I recently fixed my A/C (and boy does it work great! LOL)
Anyways, I have a problem that started cropping up once I started using the A/C. If I leave the A/C on when I start the car it will idle at about 1300 and gradually drop down and then stall out. I usually have it set to idle at about 900 rpms.
Now, it will idle really low with the A/C on. I am just confused what the IAC counts should be.
What should they be under normal idle?
With the A/C on?
At a steady cruise?
Any help would be greatly appreciated. TIA!
 
Not using conventional chips, I have to guess a bit...

But, at idle, fully warm engine, in Park, AC off.... counts should be 15-30....some would say 10-20 and a few years ago it was 20-30. Factory specs go higher. Lower the number, the less the iac does.

I would guess in drive with the ac on, the counts should be above 50 but the specs above are what really count.
 
I will try it out tomorrow since the problem only occurs when I have the A/C on and try to start the car.
 
I had a stalling problem once - turned out the iac was at 75 warm in gear. I run it at 0 now - no problems.
 
Is ECM showing an AC request? If not, its not compensating for the load and can stall. If its NOT showing the request, go to the low pressure switch, I believe one side has 2 wires, one goes to the ECM and tells the ECm "Excuse me, the owner put the control on" then the ECM looks to see if the cars been running a certain amouint of time, the car isnt WOT, then hits the AC cutout relay to turn on the compressor, and bumps the IAC the specified counts.
 
Originally posted by gnXfan
I had a stalling problem once - turned out the iac was at 75 warm in gear. I run it at 0 now - no problems.

If you are running in at zero in gear, then you have turned the iac in so far that it no longer functions and may create a "too fast" idle.
 
I just checked and on the way back from lunch with the a/c on and the car warmed up, the IAC counts were 45-48 in gear.
With the a/c off and the trans in gear, the counts were 25 with no fluctuation.
Jim, I am not sure how I would check the AC request. The only scantool I have here is the Scanmaster. I can borrow my buddies Snap On scan tool if needed.
 
I checked the counts again last night and noticed that in Park with the a/c off, they were 0 and with the a/c on they were 7-10
I also noticed that my TPS is now .48 where it had always been set at .42. Could I possibly have a TPS that is going bad and throwing the IAC counts off?
 
Lee, I have a very similar situation as yours and I was thinking the same thing. My iac's dont seem consistant at all. I just replaced my tps, and it didnt help a bit. Thinking about replacing the iac valve now. Can it "go out" guys?
 
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