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Thread: A/C issue with 02 5.3 and Cam

  1. #1
    Tuner JHPerformance's Avatar
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    A/C issue with 02 5.3 and Cam

    I can command my A/C Clutch to engage with VCM scanner and it works just fine. But when I use the switch it doesn't engage. I have triple checked my wiring, and I believe it's in the tune. I don't know much about A/C tuning as most of the swaps I do nobody runs it. Would anyone know if anything in this file would make my compressor not come on? Thanks in advance

    02 Silverado 5.3 into a 97 C1500 NV3500 5 Speed.
    ABFT Edit.hpt
    Jake Hatfield
    Central KY

  2. #2
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    Try changing you AC "Type Fitted" to just "Analog" instead of "Analog cycling." The other issue is the AC pressure switches. us the scanner to be sure the PCM is getting the AC request.
    Jaime

  3. #3
    Senior Tuner mbray01's Avatar
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    also if a/c torque, or a/c airflow is excessive as a result of a larger cam and it falls outside of the airflow adapts, it will disallow the a/c compressor.
    I have only come across this in swapped vehicles where the load is different already because of a different a/c system, then the larger cam creates more issue.
    Michael Bray
    Rusty Knuckle Garage
    Slidell, Louisiana
    20yr Master Tech.
    Advanced Level Specialist
    Custom Car Fabrication, Customization, High Performance.
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    Tuner JHPerformance's Avatar
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    Quote Originally Posted by ElecTech View Post
    Try changing you AC "Type Fitted" to just "Analog" instead of "Analog cycling." The other issue is the AC pressure switches. us the scanner to be sure the PCM is getting the AC request.
    I do not see any options for analog cycling. Or analog at all. Under the A/C tab it just has recirculating option or fan 2. I'm not running electric fans though. Is this what you are referring to?
    Last edited by JHPerformance; 10-22-2015 at 04:56 PM.
    Jake Hatfield
    Central KY

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    Tuner JHPerformance's Avatar
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    I see, what would be the fix to this if the camshaft is inhibiting the signal? It's a Chevrolet performance LS1 hotcam
    Jake Hatfield
    Central KY

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    What version software are you running?

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    Tuner JHPerformance's Avatar
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    2.24.410
    Jake Hatfield
    Central KY

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    You need to update your software. Go to your customer page and re-download 2.24. Yours is very old and they have added tables since then.

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    Tuner JHPerformance's Avatar
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    Quote Originally Posted by ElecTech View Post
    You need to update your software. Go to your customer page and re-download 2.24. Yours is very old and they have added tables since then.
    Updated software and I have the table now. I flashed it to analog and the clutch still does not come on. any suggestions?
    Jake Hatfield
    Central KY

  10. #10
    Tuner JHPerformance's Avatar
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    Quote Originally Posted by mbray01 View Post
    also if a/c torque, or a/c airflow is excessive as a result of a larger cam and it falls outside of the airflow adapts, it will disallow the a/c compressor.
    I have only come across this in swapped vehicles where the load is different already because of a different a/c system, then the larger cam creates more issue.
    I think that may be the issue. Some say on other forums to disable stall saver, Not really sure what exactly to do...
    Jake Hatfield
    Central KY

  11. #11
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    Quote Originally Posted by Jake9713 View Post
    Updated software and I have the table now. I flashed it to analog and the clutch still does not come on. any suggestions?
    You may have to select and try a few more of those to see if you can get it working, but more than likely the PCM is not seeing an input that it needs to command the AC clutch to engage. Either a pressure sensor or a pressure binary switch, depending on the platform and options the doner file used. You have to start logging some of the ac values and the status bits to determine what input or condition the PCM is not seeing. In cars that need a pressure sensor, I've had to wire in a resistor to allow the PCM to believe there is adequate pressure in the system. Sorry I don't have an exact answer. GM used about 3 main methods that I have come across so you have to do a little detective work.
    Jaime