Voltmeter is in the red zone
 

My factory voltmeter in my '88GT is reading in the red zone.
Does this mean the alternator is bad since my battery is only a few months old?

usally yes.

Is the car running?

Re: Voltmeter is in the red zone
 

take a multimeter to the battery. with car running it should read at least 13.5V or more, probally 14V, anything under 13V is bad news. do it now, cuz a bad alt will kill your battery in no time. a bad alt can sometimes be spotted by dimming headlights, dimming cluster, gauges going crazy, stereo problems, etc.

with the engine off, i think the batt should measure around 12.5V.


i picked up a 130amp from PaPerformance, lifetime warranty and charges great even w/ underdrive pullies, less whine too.

Yes, that's with the car running. Earlier tonight, when I was driving it, I noticed it was a notch below mid-point of the gauge then it went down to just above the red zone.
I'm going to have to get another battery/alt. tester cause I can't find mine.

Yeah, if it's got a bad diode it will drain your battery. Just check it with a multimeter, you don't have to have a special battery alt. tester.

it else could be the regular 2 .

Old trick here.

With the car running, disconnect one of the terminals from the battery. If it dies, its the alternator.

Never heard this one, that will show if the alt is not outputting power. But can your test show if the alt is outputting less than it should be?

Nope. I just yank it off and take it to the local auto zone for that. Since I went with the 130 alt swap over a year ago, I haven't had a problem w/ battery or alternater. Not bad for a $30 junkyard alternator. I still remember the words out of the mouth of the Autozone tech I was talkiing to about the swap. He said "See you in a couple of weeks" This was over a year ago.:rolleyes:

With the stock alternator, you'll probably have just over 13 volts at idle, at around 1500rpms, it should be over 14V. Another possibility is that the gauge has gone south.