A/c compressor kicks off at the hint of throttle....

[JDSfastGN]

I recently got my Ac back up and running. It has a new evaporator, self adjusting oriface tube, delco compressor and new accumator. I vacuumed out the system but only for about 15 mins. My numbers on a 95* day are 30-35 low side and 275-310 high side. It's been hot and this is around 1500 rpm. I bought a pressure cycling switch meant for 134 and in the driveway it doesn't cut off until 20 psi and around 4300 rpm. The problem is that it kicks off at no boost below 4000 rpm throttle just for normal acceleration blowing hot air. When it's on, it's cooling well, but it won't stay on. I put about 3.5 cans in with the proper amount of oil. Could this be an issue with not vacuuming out the system long enough? Any suggestions? Thanks.

 

[Paul Lohr]

Would it be reasonable to drive the car with your AC gauges installed? If this is R134, the low side usually will be more like 50 psi in a normally functioning system a little above idle. With a bit more RPM I think you'll see the low side on yours drop to 20 psi or less. I've never seen an untouched OEM R134 system that functioned normally with much less than 50 psi on the low side around idle.

You may have contamination. This is a guess. Without measuring the vacuum level using a micron level measuring device, 30-45 minutes of vacuum seems to remove most of the moisture. Some technicians will let the vacuum pump run overnight. This is with a good vacuum pump intended for AC service (not one of those air powered ones). This assumes the system is very well sealed. A micron level measuring device tells the technician when the moisture is gone and if the system is well sealed.

http://yellowjacket.com/sites/default/files/product_manuals/180355_Rev.B.pdf

http://yellowjacket.com/product/687

 

[RmvBfrFlght]

There are two items that will cause the A/C compressor to disengage. If the high side goes over 430 psi, there is a switch on the compressor to disengage it.

The other is the ECM controlled A/C cutout relay. This is controlled by the TPS. It may be that the chip has it set too low.

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