Idle Air Control valve
Thread Starter
Racer
Joined: Dec 2002
Posts: 260
Likes: 1
Idle Air Control valve
All
I have vibration when A/C is on and idle at 700rpm. Member suggested maybe IAC valve was bad. My Haynes repair manual illustrates only one IAC valve, but when I look at the throttle bodies on my 1984, it looks like there is an IAC in each. Is there only one, or are there two? Anyone know for sure?
I have vibration when A/C is on and idle at 700rpm. Member suggested maybe IAC valve was bad. My Haynes repair manual illustrates only one IAC valve, but when I look at the throttle bodies on my 1984, it looks like there is an IAC in each. Is there only one, or are there two? Anyone know for sure?
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
I believe two...go here:
http://forums.corvetteforum.com/showthread.php?t=872817
The guy is selling two of them!
http://forums.corvetteforum.com/showthread.php?t=872817
The guy is selling two of them!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
All C4s have one IAC per TB. Since the '84 Crossfire is the only C4 with two TBs...
ESPECIALLY because you have two TBs, I doubt they are the cause of your problem. Is the problem only at idle? Either way *I* would suspect the compressor.
RACE ON!!!
ESPECIALLY because you have two TBs, I doubt they are the cause of your problem. Is the problem only at idle? Either way *I* would suspect the compressor.
RACE ON!!!
Burning Brakes
Joined: Aug 2001
Posts: 1,238
Likes: 0
From: walled lake MI
it may also be possible that the ECM is not getting the signal telling that the A/C clutch is engaged, which prompts a bit more air from the IAC valve. if your idle speed drops when you turn your A/C on, and then starts stumbling (if it managed to keep from stalling) that would be my guess, especially if your idle is OK when A/C is off.
Burning Brakes
Joined: Nov 2003
Posts: 1,234
Likes: 5
From: Herriman UT
I had (have) the same problem with my 86. GM issued several service bulletins including #87-206 regarding A/C compressor "moan or vibration". The installation of a power steering pump rear bracket kit, P/N 10077573 was claimed to improve this condition. My car allready had the brace. I tried two new compressors with no improvement. I'm of the opinion you just have to live with it.
