I have had several issues with low idle charging problems with my car. With the A/C running, lights on and in gear my car voltage drops down to low and into the danger zone. Replaced the alternator, cleaned all connections and grounds both chassis and engine and came across a simple solution. I am lucky enough to have a junk s10 in the garage (future project) and I removed the alternator pulley off of the Trans Am and put the slightly smaller pulley from the s10 onto the T/A alternator. Now in gear, A/C running lights on I have 13.6 volts at 550 RPM steadly and the voltage in the car does not drop. The alternator was not spinning fast enough for the load at low RPM idle. Just letting everyone know that this worked for me. Don't know if it will work with anyone else.

 

or just get a higher output alternator 550rpm is pretty low for LT1s...

 

What year / configuration (L4 / V6 / auto or manual / 2WD or 4WD / AC or no AC) was the S10 Alternator pulley?

I'd like to go into Autozone with all my ducks in a row - Thanks in advance!

 

93 s10 2wd with the 2.5L four cylinder