Noahs944

Hoping some of you more experienced folks can give me advice.
I installed a standalone ecm and now the 1988 2.5l engine runs great, but my compressor clutch isn't engaging (hvac just blows hot). Noticed the Haynes manual shows the dme was controlling the compressor clutch circuit. I'd like a/c rather than just delete. How to handle this?
Regards, Noah

931guru

Haynes manual is wrong (surprise!) The AC clutch has no output from or input to the DME. The AC clutch is controlled by the AC control unit.

If the clutch has a dead short, it will burn a land on the control unit circuit board, Ask me how I know...

Noahs944

Really? Hmmm. Okay.
I was also wondering... if eventually I throw in the towel & delete the A/C; how to get the hvac to blow cool air?

ajdre11

I bought a griffiths compressor kit -think it was around $650. Installed it myself and had it charged -blows ice cold air. I’d do it again if I had to.

fortysixandtwo

Just set the climate control temperature to the coldest setting, and the re-circulation off. This will draw air from outside. Of course it will not be any lower in temperature than the outside air, but it will be better than stagnant interior air that's been heated by the sun.

Spring44

Uh, if you throw in the towel and delete the A/C, then there is nothing that you can do to get the hvac to blow cool air, because you just deleted it!. Am I missing something here?

jimbo1111

I would never delete the ac unless it was a dedicated track car.

Perry 951

The DME will raise the idle with the AC engaged through the ISV. That's about all it will do.

Did the AC work before you did the standalone? If so, you need to find out what is causing the compressor to not engage. Do you have 12V at the clutch connector when turned on? If not, backtrack to fuses, relay, and controller. If so, check the pressure sensor for continuity? If not, is the system properly charged? If so, replace sensor.

This system is about as direct as they get.

Noahs944

Thanks guys! Your comments & help is appreciated!

hp18racer

+1 on 932guru's response. I changed my car to run on Megasquirt. The AC worked as before. I did need to give the Megasquirt a signal to let it know the AC was on to bump the idle up.

Mikes3.0cabturbo

speaking from experience, most standalones should have a idle up option for the A/C, when your A/C is engaged use the clutch energise to then feeds back 12v to the standalone input which increases revs by a couple of hundred revs of so, pretty standard on standalones...

regards
mike