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Thread: a/c cycles on and off after lowering idle.

  1. #1
    Advanced Tuner
    Join Date
    Jun 2014
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    216

    a/c cycles on and off after lowering idle.

    Tuning this vehicle for a buddy. Car is an 05 ctsv 6speed with punched out ls2 to a 6.2 with ls3 rotating assembly, Ls3 heads, Ls7 cam and I believe it was Ls2 throttle body with appropriate part number and jumper harness. car use to be e85 and converting back to 93 octane. Previous owner said idle set so high 1k+ cause the a/c wouldn't work when it was idled down and loping. Now that I dropped the idle the a/c cycles on and off really fast. Not even enough time to really make a dip in idle like the problem I had on my cammed lq4 truck. Any ideas out there. Also car does not count or show long term fuel trims. If anyone would take a peak I'd appreciate it. Towards the end of the log in the PID's you can see the a/c cycling on and off on and off.
    Attached Files Attached Files
    04 Single cab Lq4/243 228r 112lsa, Long tubes, catless, Yank st3000.

  2. #2
    Senior Tuner
    Join Date
    Jun 2004
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    Are you sure the A/C has a full charge of 134A? I've seen compressors cycle on and off with low idle speeds but it usually has to go below 500 rpm before it's a problem.

  3. #3
    Advanced Tuner
    Join Date
    Jun 2014
    Posts
    216
    I'll try and throw a set of gauges on it after work today but when the idle was 1075 it would run the compressor just fine. Lowered it down to about 875 and at idle it just cycled and cycles. Bring it off idle and it stays running.
    04 Single cab Lq4/243 228r 112lsa, Long tubes, catless, Yank st3000.