strange air conditioning issue
Thread Starter
Instructor
Joined: May 2009
Posts: 105
Likes: 3
From: Kimberly WI
strange air conditioning issue
I have a 95 LT1 auto. This morning for the first time living in WI. I turned on the A/C...... everything was fine while at idle, cold air began coming out so at that moment things looked good. Then I put the car in Reverse and the motor began missing badly. So I put it back into Neutral and the idle went back to perfect. So again, while in Neutral the car idled fine and cold air came out. I put it into "Drive" and the idle began to miss again. I've fixed multiple issue with bad idles before ( I changed out my opti, new sensors, cleaned throttle body etc.....) but never have i heard or experienced the engine missing badly only while the A/C was on and in gear and then perfect idle and cold air while in neutral. Any suggestions would be appreciated.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
Can you turn the A/C compressor (center of pulley) by hand with minimal resistance?
If the IAC is not opening up more, in Drive with A/C on this will cause stumbling. The A/C compressor is quite a load for a idling engine.
Does it miss if you engage the A/C at cruising speeds?
If the IAC is not opening up more, in Drive with A/C on this will cause stumbling. The A/C compressor is quite a load for a idling engine.
Does it miss if you engage the A/C at cruising speeds?
Thread Starter
Instructor
Joined: May 2009
Posts: 105
Likes: 3
From: Kimberly WI
Can you turn the A/C compressor (center of pulley) by hand with minimal resistance? Yes it does turn pretty easy.
If the IAC is not opening up more, in Drive with A/C on this will cause stumbling. The A/C compressor is quite a load for a idling engine.
Does it miss if you engage the A/C at cruising speeds?
If the IAC is not opening up more, in Drive with A/C on this will cause stumbling. The A/C compressor is quite a load for a idling engine.
Does it miss if you engage the A/C at cruising speeds?
Thread Starter
Instructor
Joined: May 2009
Posts: 105
Likes: 3
From: Kimberly WI
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Probably help to scan in capture mode - you want to look at the A/C request; Park/Neutral or Gear signal; IAC counts; Targeted and Actual Idle and then Voltage. I'd guess that a bad Clutch Coil could be zapping the life out of the electrical or a funky gear signal would mean it's correcting for compressor loading but not Drive/Reverse or it's got the Gear, but not the A/C request, and any of this could be a bad ECM. Scanning it would narrow it down.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
Probably help to scan in capture mode - you want to look at the A/C request; Park/Neutral or Gear signal; IAC counts; Targeted and Actual Idle and then Voltage. I'd guess that a bad Clutch Coil could be zapping the life out of the electrical or a funky gear signal would mean it's correcting for compressor loading but not Drive/Reverse or it's got the Gear, but not the A/C request, and any of this could be a bad ECM. Scanning it would narrow it down.
100%, that is if you have a scan tool. Seems a lot of folks like to think you can fix computer controlled vehicles without info (FSM's) or some sort of scan tool/software.
OP: Beg borrow one to do this. It will help big time!!!
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