That makes complete sense now. Where can I get more shims from or are there a few in there now that need removing?

But why does the coil work when I jump it and not on its own?? What is impeding the relay from making a good connection??

Is it normal for the low side to go down to 15#??

 

You jumped it when it was cold and never let go, right? Once it has pulled in it will stay engaged even as the magnet weakens.

Yes it is normal for low side to go down to 15 especially if the interior fan is not at full speed. The fact that the compressor cycles off shows that the system is cooling properly. It just won't restart when it needs to.

We have reached the point that I call "over-thinking". Take the shim washers out and narrow the gap and it will work fine. You should not need to add any. Try to set the clutch up so the plate is almost touching the pulley but doesn't drag when off (take the belt off and spin pulley by hand to test that). By the book you want the gap about .010 to .020 inches, but it is difficult to measure on a used clutch because the surfaces will be uneven.

 

OP -- When the clutch engages, does the A/C blow cold?

 

Yes, it blows ICE cold.

To the prior post, If I jump the circuit even with the car hot, the compressor stays on no matter what the engine speed is. But when the relay is installed, the coil/clutch isn't strong enough and the compressor stops. That's what bugs me about this. The relay seems to lose it's signal from the computer when the engine revs above 2000rpm. But if I jump it, I can take it to redline and the compressor stays engaged.

With that happening, logic would tell me that the freon is low and the compressor sucks it dry and shuts down until it builds pressure again. But I've also learned that logic doesn't pertain to AC systems.

 

I crawled under the car this morning and tried to remove the clutch plate with no luck. The nut came off easy enough but the plate is rusted in place on the spline. Before starting I checked the gap and it was too large >0.022" but now its even bigger after trying to pry it off. Any suggestions before installing a new compressor?

 

That gap might work. Since you're having trouble there, consider it's an outside chance it's the relay. Try swapping the relay with one of the other ones. If the compressor is still intermittent, measure if it is actually receiving power when it's supposed to be on.

 

Yeah, the gap was fine. In addition to the relay, also test the compressor thermal protector and coil.

 

I just check the continuity of the thermal protector and there is a circuit when cold, so that should be good. I couldn't check the coil without major disassembly.

Also checked the fuse box under the hood. Pulled the relay out and tested the 1&2 and yes there is solid 13V of power. Also started car and tested 3&4 and there was power there too with the AC on. That said, 3&4 lost power when I goosed the engine. It shut off power to the relay when I rev'd the engine. Is that normal?

*When this all started I swapped out 3 or 4 relays just to rule out a burnt relay.

 

With the relay removed, are you measuring voltage between sockets 3 & 4? If you measure voltage to body ground at socket 3, does the voltage still shut on and off? If you measure continuity to body ground at socket 4, does continuity shut on and off?

 

New data: Pulled relay and checked voltage of #3 on ground and solid at all rpm. Checked continuity of #4 on ground and at idle no resistance(0 ohms) but with increased rpm, resistance rose to 3 Ohms+. Does that mean the ground in the fuse box is faulty?

*While I checked the above I put a gauge on the low side. at Idle it was 25#s, static it was 50#s, when I raised the rpm to 2000 rpm it went into vacuum. WTF! Is that an expansion valve or something else. It isn't normal, I know that much. Still blows cold air.