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Compressor not kicking on

ParkerFly on Tue March 08, 2016 7:44 PM User is offline

Refrigerant Type: R-134A
Ambient Temp: 70
Pressure Low: 15
Pressure High: 150
Country of Origin: United States

I've got a rat rod with a complete A/C kit from Rainbow Products LLC installed. It's always worked pretty well but I went to charge it back up today because it had leaked down over the winter and ran into an issue I haven't had before. I pulled a vacuum and completely recharged the system. After charging the compressor cycle some since its not that warm out, but I noticed today when the power kicks back on to the compressor after it has cycled off, it won't turn back on unless I rev the motor up. I did check and make sure power was getting to the compressor and it is. It just doesn't kick back on until I rev the motor.
Pressures are normal for this system. It has always run low on the low side since day one for some reason, but high pressure is in the normal range for the temp out today (70ish).
Thanks for any help.


mk378 on Wed March 09, 2016 8:37 AM User is offline

Probably just need to reduce the cluch gap. Most compressors you can take the nut or bolt off of the center shaft, remove the clutch plate, take some shim washers out, and reassemble.

Also look for the leak(s), leaking out every year is not normal.

GM Tech on Wed March 09, 2016 8:45 AM User is offline

Yeah- revving the motor is causing vibration to engage the clutch- try bumping the front of compressor with a rubber mallet when car is idling- it will probably engage.

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

ParkerFly on Wed March 09, 2016 7:12 PM User is offline

Thanks for the help, I will see what I can do with the clutch. It's a Sanden compressor by the way.
While I'm thinking of it, does anyone know a way to keep the compressor from cycling? This one will cycle off before it gets cold enough inside when its hot out. The temp knob is maxed out to the cold side but it still cycles. It gets the inside cool, but not nice and chilled like I would like it sometimes. Thanks,


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