Jim 77

My volt meter is showing closer to the 'redline' than ever before. The alternator and battery are a few months old, everything is stock. When I use power windows or the stereo, the needle drops and the headlights dim. I have two questions:
How dangereous is it to redline the voltmeter? Should I worry about the battery and safety?
What is the best way to approach the problem (what are the usual suspects)?

Thanks,
Jim

bigvette1

Get a digital voltmeter and measure across the alternator + output terminal and ground. You should be outputting 13.8 - 14.2vdc with the car running at about 1500 rpm's or so. Turning on the radio, using he windows, A/C etc will drop the o/p but nothing significant. If youare putting out much more than this figure, you will eventually cook the alternator and/or battery.

VETDRMS

It is VERY dangerous!
I just had this happen to me, my car caught FIRE :o:o:o
If you are redlining, it means your regulator is bad, or you have a
short, my guess is its a short. The wires at my starter had somehow
moved against my heatshield and deteriorated after time, it had shorted out,
and it basically ruined my harness, it cost me over 400 dollars to have fixed.
So i would possibly look there, or for any other shorts.
One thing with overcharging, the high current will "stress" the other wires, they will get hot and be more prone to shorting, or melting the jackets.

Get it FIXED before anymore driving.

Good luck, and be safe.

Jim 77

That bad, huh? No fun.
I'll pick up a digital voltmeter tomorrow. If the readings are ok at the alternator, I can assume the guage is off? Hoping, not likely.
My car was always a little like this, but it has gotten worse. I was suprised when my alt. went bad, it couldn't have been more than 5 years old. The lights also dim more than they used to.
I am pretty intimidated by the vette's electricals. I could rewire a vw in my sleep, but I owe that to the time I caught one on fire, and I can't afford to make those kinds of mistakes with the vette :cry So hopefully someone can help me see this as baby steps.
Where do I start? Should I just start at the alt. and follow every wire until I find the culprit? Are + wires more suspect than grounds? Could it be the battery cables? Why isn't there a fuse for this?
And thank you for the quick replies. This forum is great!
Jim

VETDRMS

I would check any wires near a heat source, i.e. starter.
You should first check teh alternator however, it could just have a bad regulator. Here's a good way to tell if its overcharging, or if its the gauge:
Turn your headlights on, and if they get REALLY bright when that needle jumps up, you are definitely overcharging, this was exactly what happened to mine. THe light would get bright, then turn off. Apparently there is a relay that turns the lights off if they get too hot, such was the case in my point. You should have a fusable link that will save your car, luckily the fusable link at my starter worked, and my engine isn't all oily or greasy, so nothing flamed up. If all else fails, and you can't find the culprit, you may need to take it to an electrical shop.

spiru

I'm going to have to go to a pro myself. I have a huge power drain from somewhere and can't find the problem, even when using the light bulb and battery trick.

Corellian Corvette

Spiru -- please post your problem and solution when you get it worked out. I'm having some wierd electrical problems and would like to learn what you find out!!

Thanks! :cool:

ZD75blue

I recomend irish springs soap to get rid of that terrible burn your nose smell when you boil a battery... Not fun

stickboy

spiru -- I'm having this same problem, the battey will drain overnight sometimes, then other times it will hold it's charge, I think it's the alternator, but I'm not sure yet :nonod:

I know the battery is good, it's new, and it hold its charge if I disconnect it


[Modified by stickboy, 9:01 AM 2/14/2002]

Vader953

Have any of you ever heard that 78's are notorious for charging problems. Something about that year is really fishey. I've heard this from several enthusiasts. Mine will slightly/moderately undercharge some days, and overcharge on others. Don't know what the hell the problem is. Alternator/battery are new and the correct sizes.

Oh well.

Anybody ever heard of this though?

Jim 77

Ha ha ha. Funny, real funny...
The needle stayed really close to redline all day today. Then finally I made my way to NAPA, and bought a digital multimeter. So guess what happens on the way home?
You guessed it... no more redline. Fixing my car is like taking an angry 3 year old to the barber. :rolleyes:
I am going to get familiar with the wires for when the problem returns. :rolleyes:
Jim

LAvetteman

Jim, your problem sounds like a loose ground to me.

spiru

Same exact deal here. Its really starting to bug me big time!

spiru

<<<<<Have any of you ever heard that 78's are notorious for charging problems. Something about that year is really fishey. I've heard this from several enthusiasts. Mine will slightly/moderately undercharge some days, and overcharge on others. Don't know what the hell the problem is. Alternator/battery are new and the correct sizes.
Oh well.

Anybody ever heard of this though?>>>>

This is the frist I've heard of it. :cheers:


[Modified by spiru, 5:38 AM 2/15/2002]

silver 80

do you do your work durring the day? I had a 79 that would drain the battery too. turned out that the glove box light was on all of the time.
also you might try and get a test light, disconnect the neg on the battery, hook the test light to the battery and the neg cable. If the light is on then you have a drain, then you go the fuse box and start removing fuses until the light goes out. you have found the circuit that is draining your battery.
worked for me
tom

silver 80

I've got an 80 right now doing the same thing, while doing other things to the vette, i replaced my head light switch, and the volt meter went back to normal.
I think I have a short in my dash lighting system. they never worked when I got the vette looked at the fuse and someone had stuck a mini fuse in where a reg fuse should go. now the headlight switch is getting hot to the point of smoking the ceramic on the headlight switch. take the fuse out for the dash lights and no more smoke
:cuss
so it looks like I get to take the dash out this weekend and find the short.
tom

redvetracr

Jim77,
It sounds like a bad (stuck) voltage regulator inside your alternator, and you will probably cook your battery. I would take it off (the alternator) and take it to any GOOD rebuild shop (NOT a peep boys) and have them check it. ....redvetracr

still-learning

I actually saw this happen w/ mine. I was driving the car and I noticed that all of my lights were MUCH brighter than normal and the needle was bouncing all over the place. This included the electric tach. I took it home immed. to work on it. Don't remember why but I checked w/ the battery and it turned out my ground wire was loose at the battery. Tightened it down and no more problems.

Good luck. Hope it is something easy. :cheers:

Tim M.