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That proves the compressor is indeed engaging (engine stalls out with a/c button engaged).

Sounds like the BAC isn't working like it should. Plug off it? Pins in the elect plug pushed back?

 

You should hear the difference when the A/C is on vs. when it is off. If your idle drops when your A/C is on, you need to fix the idle air control valve. If your A/C runs but it is weak, you can usually top it off with some Freeze 12 (hunt it down). Otherwise take it to a mechanic for a full flush, fill and leak test. Ask him how much he charges for R12 and if it's a fortune bring in your own Freeze 12. 3 cans including 2 regular and 1 with UV dye and oil IIRC.

If you repeatedly top it off with R134a you'll drastically reduce the life of the compressor, besides getting worse cooling. Emptying all the R12 first is even worse. You need to replace parts to do a real conversion to R134a.

 

This is what I get for not reading the thread carefully before posting. I think BAC is same as idle air control valve, or what I meant anyway :P.

 

im having the same problem?? my car runs fine till i turn my a/c on when i turn my a/c on my car stall and i have no idea what going on at all

 

how about search ? and read stickies ?

 

well here is the deal
my car runs fine , but when i turn the the a/c the car stall not all the time just when the car is already warm up and when im driving the rpm nidle acting up it keeps going up and down the stall and the battery gauge drop to 12..... do you still think is a problem with the BAC???

 

Yes, it sounds like the issue is with the BAC. When the car wants to bog down with the a/c activated try turning it off and then right back on and see if this changes anything.

 

BAC is there to maintain the idle when a LOAD is put on the engine.

BAC cannot do this all by itself. The REAL idle needs to be set at or near 750-800 rpm so the BAC won't have to strggle so much to KEEP the idle at a 750rpm.

If you car is idling and is fully warmed up, turn the a/c on and then pull the plug off the BAC. The rpms should drop when the elect plug is pulled. IF there is no change in rpm.......BAC transistor is kaput inside the ECU most likely if the elect plug that attached to the BAC does not have a pushed back pin.

The above applies to engines that are idling below 800 rpm. IF you have the idle set to 900 or 1000 plus rpm........BAC does not work at those rpm so forget what I wrote.

A simple check of the BAC is to pull it off the engine. Leave its elect plug on and look inside the BAC. Put the key to START with the small trigger wire off the starter solenoid. The BAC should hold full open if the key is HELD to Start, proving the ECU is good. Normal operation of the BAC is it working a approx 120 hz. Like cycling a 120 times a minute............as long as the engine is below???? 900 rpm or there abouts.

Never pry on the guts of the BAC.

 

well my car show rpm at 900 but when the a/c turn on it drop to about 800-700 and then the nidle start to go nuts by goin 700 to 1000-700-1000-700 and stall and i crack the car back on and it runs fine for another 5 min then start again i wonder if the problem may be electrical ???

 

TPS set correctly ?

 

i dont know !!! how can i check??? and some friend of my thinks my tps may be bad?? also can can i check to see if it is??

 

90% of the time ur TPS is working, its just that its not set correctly. I was one of the 10% unlucky ones to have a way out of spec TPS (failed).

The FSM will tell you exactly what you need to do.