SOme background info:
I bought the car with broken AC. The R134 had all leaked out of the compressor. I replaced the compressor and recharged the system. I put in 50psi on the low side, and the hi side corresponded with 300psi. THe AC worked fine for about 3 weeks, then it Just quit working one day for no reason.

THe compressor won't kick on, but it's brand new. I just checked the low side pressure, and it was 95psi!!!! Is there a safety switch that will disable the compressor if the low side pressure gets too high?

I'm wondering if the AC will work again if I just bleed the low side down to 55psi.

I'm also wondering if there might be a clog in the system somwhere. Is there any way to check this out? ANy suggestions?

 

Did you replace the oriface tube and accumulator?

The low side will drop when the compressor cuts on......I don't remember how it is set up but check the pressure switch, you should be able to back probe it,, and a service manual will have the values. Sory I'm not more help but its been a while since I have done any A/C work

 

I did not replace the orifice tube or accumulator. Is that a common point for the AC system to develop clogs?

 

yes, and they should be replaced anytime you replace the compressor, most won't warrenty the compressor if you don't

 

Not all camaros have orifice tubes mine has an expansion valve. You can jump the connections on the A/C relay to force the compressor on..

 

4th gens don't have orifice tubes.

 

If I pull the relay, which wires do I jump to turn it on?

 

95psi on the low side sounds right if the compressor is not running

 

Pull the relay off and on the bottom of it the connectors are labeled with numbers. You want to jump (with a piece of wire or paperclip) 30 to 87A. On the side of the relay there is also a diagram, it shows a curved arrow between 30-87A showing that, that is the live connection. I wouldn't drive the car aroudn.. with it jumped.. I did it just to get my system to take refridgerant... something was clogged... and not enough would go in to make hte compressor kick on..

 

if the system is low, a code will set, and the PCM will keep the compressor off until the code is gone and the pressure is correct


easiest way is to jump the relay till its full, then reset the PCM

 

I tried that and the compressor still would not kick on. That makes me think that the compressor itself might be the problem. THe clutch might be broken. I don't know enough about them to know for sure though. The front plate assembly feels loose.

I bought an OBD1 code scanner today. (this is all happening on a 94 Z28 BTW)The code scanner would not show me any codes. It would not even show code 12, which indicates that the system diagnostic is working correctly. My hi beams and cruise control don't work either. I wonder if I have a deeper problem. Maybe the PCM itself has suffered a partial failure. I know older OBD1 PCM's used to fail occasionally.

FUrthermore, when I turn the AC switch to "ON" in the car, the RPM jumps to 1300 and then settles back to idle. That tells me that the PCM is attempting to run the AC compressor, but the compressor itself won't kick on. LIkewise, when I turn the AC switch to off, the RPM drops to 600 for a second, then goes back to idle, as if it's decreasing engine output due to the decreased load of having the compressor off.

 

I just pulled the electrical lead that plugs into the compressor. The black wire has insulation missing. I wonder if it has been touching metal and shorting out. I then hooked up a multimeter to the compressor connector just to experiment. With the switch on, there was very little resistance, and only like 0.03volts.

Does that connector provide continuous current to the clutch, or does it only provide a quick pulse to engage and disengage the clutch? I couldn't see if it was a pulse or not because my head was in the car when I turned on the AC switch.