My 89 almost dies when ventilation controls are on.Help

[carlsho]

About a week ago, I was driving with my heater on and I slowed down, pressed in the clutch and my rpm's went down to 400, then up to 900-950 again. When I shut off the heater controls the problem was solved. Does anyone have/had a similar problem. When I drive with the heating/ventilation/ac controls off my car runs like a charm. When I put them on I have to watch out and keep my eye on the rpm's, because from time to time my engine's rpms go way low, sometimes it dies, sometimes it's about to die, then it goes back up to normal.Any feedback, thanks
Carl B.

 

[Ishodu]

It most likely the AC that is sucking your power away. You can try to reset your idle it may help you out. Try a search on that its been talked about many times. Try using the heater controls on vent, the AC wont come on then.

 

[qiksho]

Had this problem on my 89...not exactly like yours however.

My A/C clutch was nolonger gapped properly and would chirp every so often and almost stall the engine. I know the a/c system runs with the defrost on, but I don't think it runs under normal heat

 

[Tom Higginbotham]

I had a similar problem...my '93 was dropping to around 500 RPM's and sometimes dying when the A/C was running. Car acted fine when on VENT or when the unit was off.

"Betterman" suggested I reset the idle, so I did a quick search here, found the procedures to reset the idle and the problem went away.

Good luck!

Tom

 

[SonicRiot]

If the air gap (for the compressor clutch) is out of spec, resetting the idle isn't going to solve anything.

Your problem sounds like it has absolutely nothing to do with the HVAC system... just a coincidence. Think about ti: the heater cannot bog the engine or stall it out. An A/C compressor can seize up or a pully bearing can go bad, but you said that the HEATER was on, so it has nothing to do with the compressor.

So, run codes and look elsewhere... like the IAB/IAC.

 

[DHMag]

what about a vacuum leak ?