yurizx6r

I think it's the alternator. I drove it back to my buddy's house today (20 miles) with everything off and the voltage meter was perfect. No sounds or issues at all. On the way back I turned the vent on full blast and the voltage meter went to the half mark. Then I turned on the radio and it went into the negative side (say at the 40% mark). When I drove it like this it started to make a funny noise. I then drove it back with the radio off and the headlights on. No issues. I would come up to a stop light with my foot off the brake and it would be perfect. It was only when I had my foot on the brake that the voltage meter would start to go down. Probably the brake lights are taking up that extra bit of energy and it's just enough to stall the car. I'm thinking that what is going on is the alternator is going bad and not generating enough power to supply more than one accessory at a time. Since I had the radio and headlights on it was taking more power than the alternator was generating, add the brake lights and...stall, so the car is stalling since the ECU is not getting enough power...? What do you think?

yurizx6r

UPDATE!!!! It was the alternator. I did a 3G upgrade. I also did a before and after test.

Old alternator:

Baseline idle ------------------14.47 Volts
With headlights turned on------14.38 Volts
headlights and air vents on-----12.80 Volts (and unstable idle)

*Voltage meter was between "M" & "A"

New Alternator

Baseline idle -------------------------14.50 Volts
With headlights turned on------------14.45 Volts
headlights and air vents on---------14.36 Volts (stable idle)
Lights, air vents, & radio (to max)- -14.30 (idle perfect)

*voltage meter with everything on was between "R" & "M"