AC Rough Idle/Overheat
Thread Starter
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
AC Rough Idle/Overheat
Almost got all the "bugs" out of my '85, but could use some help. Car seems to run great, but when I turn on the AC the rpms drop (doesnt want to stall, but runs pretty rough at idle). I have to turn on the AC because I dont think both fans are coming on like their supposed to and it will overheat. Never had this problem before putting new heads on. To me it seems like these two problems could be connected.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Only the Main fan comes on with a/c.
Rough idle with an a/c request is either a crapped out compressor; loose or missing mounting bolts and brackets; or funky ECM control. You can check that the bolts are tight and make sure the outer hub of the compressor - bolted to the compressor shaft - turns freely and with minimal resistance with the belt removed. To check out the ECM and idle components, you need to scan it. That should show a "YES" in the a/c frame whenever you hit the "on" button and the IAC counts should increase 10 or so when the compressor clutch engages.
Rough idle with an a/c request is either a crapped out compressor; loose or missing mounting bolts and brackets; or funky ECM control. You can check that the bolts are tight and make sure the outer hub of the compressor - bolted to the compressor shaft - turns freely and with minimal resistance with the belt removed. To check out the ECM and idle components, you need to scan it. That should show a "YES" in the a/c frame whenever you hit the "on" button and the IAC counts should increase 10 or so when the compressor clutch engages.
