A/C issue with 02 5.3 and Cam

Printable View

10-21-2015
JHPerformance

1 Attachment(s)

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.
Attachment 54276
10-22-2015
ElecTech

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.
10-22-2015
mbray01

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.
10-22-2015
JHPerformance

Quote:

Originally Posted by ElecTech

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?
10-22-2015
JHPerformance

I see, what would be the fix to this if the camshaft is inhibiting the signal? It's a Chevrolet performance LS1 hotcam
10-22-2015
ElecTech

What version software are you running?
10-22-2015
JHPerformance

2.24.410
10-22-2015
ElecTech

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.
10-22-2015
JHPerformance

Quote:

Originally Posted by ElecTech

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?
10-22-2015
JHPerformance

Quote:

Originally Posted by mbray01

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...
10-23-2015
ElecTech

Quote:

Originally Posted by Jake9713

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.