I have a 1990 convertible when I use my AC “all the time as I live in Las Vegas” I have noticed that when I push the breaks the RPM’s drop and some time stall the car. Any one have any ideas?

 

normal to some degree if your alt is getting old, if it is an idle problem, then it could be your BAC valve.

 

when i do that, my car's rpm's drop a little and the car shudders a bit... especially with the headlights on... i was told this was partially b/c i have a lightweight flywheel...

 

Thank you I will look into the Alt.
I checked and cleaned the BAC and it is working fine. When my head lights are on and the brakes are depressed with the AC on the RPM's surge from 500 to 1000 till I take my foot off the brakes then the idle is normal.

 

what is your voltage dropping to???

have you updated the grounds on the engine and battery yet?

 

The voltage drops to 11 or 12
I have not attempted to modify the engine ground wires yet, I have been looking for a good write up the one on the sticky is mediocre IMO.

 

any drop under 12.5 volts and you are running on only battery power, your alt can not put out enough juice to run the car correctly. all sorts of electrical problems will alos start happening.

You need to fix your charging system

 

What do you think of the FD3 alt swap?

 

It's a great swap. Talk to silverrotor.

 

I just ordered one.