stalling under ac/defrost

[jeffm]

my '93 mtx stalls when the ac is kicked on. I have no codes, strong battery and this girl has never acted like this. I reset the idle 42 times with no luck. Peace be with you.

 

[94'whiteSHO]

not really sure, but it could do with the AC compressor sucking up to much power, check the grounds and do your codes! http://www.shophoenixproject.com/eec/eec.htm
this should help you greatly ^ and its free!

 

[Rockledge]

The PCM should be kicking up the idle a notch when the A/C compressor engages. This is done by virtue of a signal to the Idle Air Control (IAC) valve.

A bad IAC is much more common than a bad PCM. Any other idle problems to speak of?

 

[NotSoSlowSHO]

Are you sure you are resetting the idle properly?

 

[KevinB]

I actually have the same exact problem. My idle sometimes drops low, and if I use any accesories that put a load on the engine, it will stall, or almost stall.

 

[ohfosho]

try the idle relearn first...unplug you battary for 5 mins, and then hook back up drive till warm and then sit and let the fan cycle on and off.

 

[doclees]

I was recharging my ac today. The idle was almost stalling until the system was charged. Then it settled in with the compressor engauged. Then the high pressure line popped off - but I digress. So does the system need a charge?

 

[jeffm]

Thanks

No other idle problems to speak of, I will look in to the IAC/PCM, hopefully this will solve the problem. With no codes I of course frustrated. Thanks again.

The PCM should be kicking up the idle a notch when the A/C compressor engages. This is done by virtue of a signal to the Idle Air Control (IAC) valve.

A bad IAC is much more common than a bad PCM. Any other idle problems to speak of?

 

[jeffm]

I believe so, after disconnecting the battery, restart with hi beams on, max ac, turn the wheel left/right, and depress the brake. This seems to have worked in the past. Thanks for your help.

 

[jeffm]

I don't believe so, nice cold r12. Thanks.

 

[sdpatt]

To properly let the EEC relearn the idle after a battery disconnect or after unplugging the keep alive memory connector near the battery, start the engine and DO NOT TOUCH THE ACCELERATOR PEDAL FOR AT LEAST 30 SECONDS. The other loads can be applied after that time as the EEC is learning for 70 seconds.

 

[jeffm]

To properly let the EEC relearn the idle after a battery disconnect or after unplugging the keep alive memory connector near the battery, start the engine and DO NOT TOUCH THE ACCELERATOR PEDAL FOR AT LEAST 30 SECONDS. The other loads can be applied after that time as the EEC is learning for 70 seconds.

Thanks, I believe I am doing it right, but I will try again. Should I replace the IAC? With no codes I am a bit stumped...