Cascade Crew

iansane · Posted: Fri Dec 16, 2005 1:03 am Post subject: Can the volt guage go bad?

I'm having this funky problem with my charging system.

I start the car up and it is charging fine. The guage shows a hair above 13 volts. The lights are bright and everything seems normal. Awhile after I start driving after the car has warmed up; it's usually not for at least 20 minutes or so; the guage drops down to about 8 volts. It doesn't seem to be caused by anything specific. I never notice one specific thing that does it. The lights stay bright, and it stays that way regardless of if my fans are on, radio is on, windows, or lights are on.

I had the alternator tested on the car and the machine just went crazy on me and just said "charging system problem." I drove around for a bit, made sure it said it was saying 8 volts and stopped back, pulled the alternator off and bench tested it while it was still hot and it said it was fine--3 times in a row.

I don't ever have problems starting or dead batteries. Always starts fine.

I'm confused. I've checked the battery terminals, they're good and clean. Pulled 'em off and cleaned them some more. Checked the wiring to the allternator/battery/starter everything seems tight and clean. Nothing seems to be wrong with it, it just bothers me that the guage is indicating something wrong when nothing bad is happening (to my knowledge)

Any ideas?

Dewey316 · Posted: Fri Dec 16, 2005 6:57 am Post subject:

when it gets warm and drops down, pop the hood and pull out a volt meter.

My gauge reads 16v when ever the car is running, I checked it with a volt meter, it is really right at 14v.

iansane · Posted: Fri Dec 16, 2005 8:06 am Post subject:

And check it where? The battery? At the alternator itself? Or it should be the sam everywhere?

Dewey316 · Posted: Fri Dec 16, 2005 9:12 am Post subject:

I would check both. You should get near 14v at both places.

alloy · Posted: Fri Dec 16, 2005 9:26 am Post subject:

Take is to a schucks and have them test it. They have a computerized meter, and it reads out exactly what the problem is. I've found alternators that charged fine when the car was cold, but give them 20 mins and they test bad after the engine/alternator warms up.

And FYI, there is no way to tell the meter at schucks to read wrong. It will even tell you if the posts are corroded it's that sensitive.

BigDaddyVu · Posted: Fri Dec 16, 2005 6:04 pm Post subject:

Another thing that could go wrong is the battery connections. Usually the bolt on style. pull it off and check if there is any corosion i cut off the rubberband off the connector which holds the bolt usually have rust there. and clean the area.

iansane · Posted: Fri Dec 16, 2005 7:10 pm Post subject:

Like I said in the first post, I took it into Schmuck's to test and the machine just said 'Charging System Problem' (which it does when it gets a lot of interference). It's real easy for me to do that because I work at Schuck's. Laughing

As for the terminals, I tried cleaning them and it didn't do much to help. I'll have to check the voltage on both the alternator and battery with just a standard volt guage because whatever interference caused the machine to not show an actual voltage output.

Shitty. I even waited for the car to warm up (takes a half hour to get to work). The bench test (when I pulled the alt. off) showed the alternator as good. I'll probably end up just replacing it because it's a reman'd ACdelco from 95.

Thanks guys.

alloy · Posted: Fri Dec 16, 2005 8:28 pm Post subject:

So do I. I'm a key at 53.

Interference with everything off usually means a power draw somewhere in the system.

iansane · Posted: Sat Dec 17, 2005 12:44 am Post subject:

Everything off? What do you mean?

I work at 403 by the way. Well, for a bit, I may be transfered to 1392 or 90.

alloy · Posted: Sat Dec 17, 2005 7:48 am Post subject:

Well, when the meter say system noise, it usually means something is creating a power draw. Usually I find it's stereo amplifiers creating the draw. Could also be a short, or even a broken plate in the battery shifting around.

chevymad · Posted: Sat Dec 17, 2005 10:16 am Post subject:

Definately check on the voltage while the problem shows. As for could the guage be bad.. yes. My oil pressure guage has been doin similar things. When I first start the car it pegs out and reads normally.. hit the right bump or whatever and it'll drop down and read 20psi. Sometimes if I smack the dash it'll work again. Took the dash out once and tightened everything up but still does it. It's an ebay dash and i've been too lazy to swap my original gauge back into it. Kinda scary beings its oil pressure.

NHRA427 · Posted: Sat Dec 17, 2005 11:36 am Post subject:

Go buy a cheap aftermarket volt gauge and just install it for a while and compare while your driving. You probably know someone with one hanging around not being used. I never trust the factory gauges, seen way to many screwed up.