Hello everyone! New guy with question: I have just finished the a/c in an '85 Fiero Sport and I’ve run into a problem. This particular car had eaten the original DA-6 and 2 HR-6 compressors before I finally stopped letting other people twist wrenches on it (and add scratches to the paint) and did the work myself. I flushed everything and thoroughly blew it all dry, installed a new compressor, OT, o-rings and accumulator after figuring out why the others had failed (warped rear bracket pulling the sections out of alignment), distributed 8 oz. of PAG 150 into the various components, pulled vacuum for 3 hours, charged w/35 oz. of 134, and checked every joint and line for leaks. Should be cooling like a champ, but the clutch won't engage properly. It locks up for about 5 seconds at first startup and then only for a couple seconds at a time at 3 or so times per minute after that. The clutch connector is tight, the diode is intact, both compressor switches (which came out of the previous compressor, a NAPA Cold Power China special) are in and connected, and the cycling switch is apparently working (I jumped the connection for a few seconds and it made no difference-still no lasting lockup). Chased it down electrically per the Pontiac service manual and everything down to the relay is in spec. Jumping the relay wires engages the compressor but not the ECM so the engine drags down and stalls. Static pressure is within 5 degrees of ambient temperature but the average live pressure readings are 25 or so psi low side over 50 high side. The air turns cold for the first lockup but then the low side plummets to shutoff pressure before the high side has the chance to rise past 60. I don’t think there is a high side blockage because temp is consistent from one end to the other and besides, the compressor won’t run long enough for me to find any frost spots. What gives?
Oh, and the 4 Seasons compressor has 10 cylinders instead of 6 and it didn't come with a pressure relief valve-just a bolt-like screw in plug that doesn't look temporary. Is the lack of a relief valve an environmental thing?
Finally, does anyone know if the switches are the same for both brands of compressor? I'm wondering if that might be what's wrong but I'd like a second opinion before I tear into everything again.
[This message has been edited by 2camsam (edited 08-24-2013).]
