Has anyone seen or experianced anything like this? On this 93 SC2 it runs like **** then dies when I hit the A/C button. Then after starting it with the A/C button pushed off it doesn't accelerate well at all, AFR reads lean, bogs clear down etc. Letting it sit for a while or disconnecting the battery for a sec then starting it makes it run normally again so long as I don't press the A/C again.nThe compressor isn't seized, I manual engauged the clutch and started it and it ran good until I hit the A/C again.I'm leaning towards a short somewhere in the control circuit or possible ECM issue, but wanted to pick yalls brain before I tear into it a. ton more. For kicks and giggles I did already put in a different IACV.

I switched PCMs with another one I had. It ran great until the A/C was turned on which instead of dying it just runs really bad even after turning the A/C off. Switched back to the factory PCM and it does the same things as in the original message.

 

You state that the compressor is not seized and that you can manually engage the AC clutch. I have you actually confirmed that the clutch will engage by itself? You reference pressing the AC button, but does the air conditioning function properly when you turn it on and turn it off via the button?
Also, the auxiliary fan under the hood should always be on when the button is pushed in. This is a command designed into the PCM. If it's not coming on, check the fan relay. The fan should not always be running. Only with the AC turned on and functioning, and when the ects reading is sufficiently high that the PCM turns it on.
SES light on?
Any OBD1 codes?

 

With the factory PCM when the clutch engages the car ides down and dies, with the other PCM it runs and doesn't die, but runs poorly with that lack of acceleration, AFR lean, etc.
Fan is on with the A/C I need to double check if it's always on or not.
no SES light or codes no.