I went to leave work yesterday evening and the car was running kindof strange. I flipped the switch to check the voltage and lo and behold, with the a/c on, lights on, and radio on (loud), AT IDLE the voltage was 14.1 :confused: Maybe this is ok and all, but I've just never seen the voltage get that high on any car and it doesn't usually do it on this one... for most of the drive home I was running ~3.8-4.1 volts...

 

My 92 normally runs @ 14.1 or so. At idle at night with lights etc it'll drop @ 13.7. I'd say no problem based on my random sample of one other Vette!

 

I just replaced the alternator on my '90 and the volts run 14.6 no matter what's happening! Lights on, a/c on full, at idle.... 14.6!

Is that too high?

 

Wow! Mine normally runs 3.6-3.8 and it's less than a year old...

 

You mean 13.6 to 13.8 volts. Your car will NOT run on 4 volts.

 

where in the world did you get your alternator....i need one like that.
at idle with AC on, aux fan on, radio on, i hit 11.7 volts....i would LOVE to have 14+ volts at all times!!!!!

 

Believe it or not, but I got it at Pep Boys. Brand new unit, not the rebuilt ones they sell. It seems to work great!

 

What was the temperature - ambient and coolant? Both have an effect on alternator output. Based on the dozen or so alternators I've put in my car, I've seen anything from 13.6 to 14.2 at startup to 11.6 at idle with all accessories on and the engine temp showing 228 - 230. In an effort to find more amps, I tried a 6 guage charging wire once, but it didn't do any good and because it was unprotected, I went back to stock. I also tried a smaller diameter pulley, thinking a few more RPMS might pick up some slack. At best I got .1 volt. I was able to pick up .4 volts once. This was due to resistance in the ignition switch (which I picked up on my DVM) and after cleaning it with some electrical cleaner, I got that much voltage back at the cluster guage. For the 3 or so clusters I've had in my car, all of the votimeters were .2 volts less than charging voltage at the battery. The biggest accessory draw on the system seems to be a/c blower (and the rear window defogger can zap it pretty good too). I've never read it, but my a/c buddies tell me that a typical GM blower will draw 20 to 22 amps (highest blower speed), so if you consider that, along with both fans working at idle, I can see why Chevy tells you to turn the a/c off (at least turn the blower down) at idle when the engine temp gets up there - the system, with CS 105 amp alternator, just can't keep up. In fact, I'd be surprised if these pieces of crap put out more than 40 amps at 600 rpm on a hot motor and unless you've got a fully charged battery to make up the difference, performance, at idle, is going to suffer (and as most of us seem to have experienced all too frequently, the stock alternator - GM or aftermarket rebuild - is going to fail).