86T4R_project

it's now almost summer again which means I'm more inclined to get my ac working. Summer 2020, I installed a new compressor (came with dryer, expansion valve, and all new o-rings/gaskets) and recharged with r134a. I also flushed the system with cleaner and compressed air. the system worked okay (wasn't expecting modern performance) but after a few days the compressor no longer engaged. I assumed I had a leak but as I was working from home and barely drove anyway, I wasn't very enthusiastic to get it checked. fast forward to this weekend and I got the system leak tested: no leaks and holds pressure but the compressor won't engage. The system is charged right now and I can jump start the compressor by touching the electromagnet lead right to the battery. The clutch fully engages and rotates however even after holding it like that for a couple minutes, there is no change in the air temperature out of the vent. Also, there is no discernible idle fluctuation when the clutch engages. When it was working last summer, there would be a noticeable change in idle and sound and then the VSV would kick in and raise the idle back up. I've checked the ac amplifier with a diagnostic check I found on this forum but that was for a 1989. I assumed 89 and 86 would be the same but looking at the 1986 specific FSM and 1986 electrical wiring diagram I have, it appears the connector is different and even between the two 1986 manuals, the connector is different (86 FSM doesn't have the ac amplifier wiring diagnostic check like the 89 picture I found). I have confirmed that the single wire from compressor to ac amplifier has continuity.

To me it looks like the compressor clutch activates but the compressor itself isn't actually compressing i.e. something failed internally and it just free spins. additionally, something is not right electronically because clicking the ac button doesn't activate the clutch. My theory is that something is clogged, despite being flushed (it's possible I wasn't thorough enough), and that instead of a hose connection blowing out, the compressor failed internally. Has anyone experienced this type of issue? Is my theory way off base? What could be the issue causing either of these problems? Does anybody have a manual for a 1986 that shows how to check all the ac wiring?

Dernation

If you bypass the circuit by jumping out the clutch it won't idle up because you bypassed the signal to the VSV and the EFI computer which controls the idle. Here is the 2 pages u need to troubleshoot

Efi in bottom rh.

A/c amplifier and switch on rh

86T4R_project

Ah that makes sense why the idle up wouldn't work! The idle isn't dropping at all though which is why I think there's no load in the compressor. I remember when it was first working, the idle would noticeably drop but now nothing.

Thanks for those 2 drawings, I'll take a look at those today.