Compressor locks up

[68Holdon]

I have a 68 camaro that I installed a Vintage air system in Two years ago. Worked great never a problem until now. I removed the engine and put in a new ZZ502 with a Retrotek EFI system. I hooked up the wire from the ecm to the wire going to the compressor after the binary switch. The ecm is supose to raise the rpm when the a/c is swicthed on. But as soon as I turn it on it locks the compressor up. It will smoke the belt and kill the engine. Dont know what to do or look for.

[GetMore]

First off, it sounds to me like your compressor is seized. Maybe it got filled with oil.
It doesn't sound like a wiring problem.

Try turning the compressor by hand. You should be able to, even with the belt on, since the clutch disconnects the two. There should be some resistance, but not too much. If it is hard to turn, but you are able to turn it then keep turning it for a while to pump the oil through it.
My guess is that you had the compressor sitting kind of low when swapping the engines and the oil settled in the compressor or near it.

[Mossimo777]

I would second that your compressor is seized. If it smokes the belt then internally it is not moving.

[68Holdon]

Okay now that i think about the oil thing makes sense to me. I can only spin the clucth about a half turn by hand before it locks up. If it is full of oil how do you fix it? Thanks.

[KUL FIR CHICK N]

Did you discharge the system and remove the compressor when you did the engine swap, or did you just lay it to the side? If you just hung it off to the side with the system still charged, I'd guess that you drained the crankcase oil into the head. There's a crankcase vent in the compressor (at the top when the compressor is mounted with ports up). I'd take it off the bracket and let it sit clutch down for several days. If you're lucky, the oil will seep past the rings and back into the crankcase. If not, you'll need to pull the head (carefully and cleanly) and remove the oil. You have to measure how much you removed and be sure to get it back into the system. This job is best left to an A/C tech. The proper oil charge is critical.

[GetMore]

I know that when you fill the compressor you are supposed to turn it by hand to pump the oil through without risking damage.
So, try turning it by hand. If it does turn rotate it until it starts to turn with minimal resistance. Then you should be good to go.

[68Holdon]

Thanks for the replies I will try to let the oil work its way back as suggested. if that dosnt work I will take it in and have it done. Thanks again.