A/C use stalls engine

[teppichkopf]

90' Legacy auto:

 

Sometimes when I use the A/C the engine will stall at a intersection. Or hesitate and want to stall out. Ideas?

[jcniest5]

Check your charging system (alternator) to make sure it's still in top charging condition. Whenever you use AC, if the alternator isn't at the top condition, the AC uses a lot of power and the reduction of power (because of mediocre charging) will stall your car. Perhaps someone with a more knowledge in AC can pinpoint the exact problem but that's as far as I can guess.

[EOppegaard]

Definitely sounds like a lack of juice problem here.

 

I concur that you should check the electrical charging system in the vehicle.

[Flowmastered87GL]

I know its an old school car, but my 88 GL would do that because the throttle position sensor or airflow sensor or something was going out... I forget which.

[rweddy]

Definitely sounds like a lack of juice problem here.

 

I concur that you should check the electrical charging system in the vehicle.

Actually I think this has nothing to do with alternator or charging.

When you run your ac, the compressor clutch engages and takes power from your vehicle. You have a idle sensor that is sets the idle higher when you turn on the ac. So instead of idling at 700-800 rpm you engine will sidle around 1000-1200 rpm.

This is also why when you run your ac frequently you get lower gas mileage, the compressor for the ac take quite a bit of power to run.

I am not sure if there is a screw on 90 Subaru's but the senor could be bad or you need to turn the ac idle screw up if there is one on a 90.

[rallyruss]

three words.

Idle air control

 

check it out. the TPS does play a role in this too. as it needs to know its at idle and has increased load.