NTChrist

Howdy, the problem started this evening, when I went to start my car. It's been sitting for a few months, and I figured I'd probably best get the oil flowing, gas moving, etc.
I started the car up, and I immediately noticed that the voltmeter didn't move past about 9-10 volts. I believe this indicates that the engine was running off of the battery, right? After swearing a lot (didn't help), whacking the alternator (didn't help either), and restarting the car, I shut it down for fear of losing too much battery power.
The alternator is a year and a half old. Could sitting have damaged the alternator to the point where it stopped working? It's got a warranty, but I have to take the part with me 800 Kms - to Canada. Don't worry, I'm not going all that way just for the alternator, I have another reason. I'd still be pretty pissed if I hauled it all that way, and when the part store tests it, it turns out that its working fine.
Could there be anything other than the alternator that could make it so that the battery wasn't charging?
Thanks for the responses.

tanager11

Is it possible that you left the battery connected and it just got discharged (not sure how long you let it run and if it had sufficent time to re-charge the battery if this is the case).

NTChrist

No, unfortunately, the voltmeter would still read the usual amount of volts if th battery was low. The alternator would pick up the slack.
I let it run for about a minute and a half, still no change, except the volts were slowly dropping.
Any other ideas?

jdrobley

i would check your connections by the alt to make sure there is no corrosion. also take a voltmeter and check that there is power getting to the alt in all the right places and also verify the gauge readings.

TBI305Camaro

could be the guage...i know my gauge is really messed up and it tends to affect the computer somewhat...at night with a full load (lights, heater, and cd player) my voltmeter reads at around 10volts and at idle its horrible bouces back and forth and stuff well anyways i did a load test on my alternator and it puts out almost 100 amps at idle with a full load so that isnt the problem...gauge is just outta whack

Berlinetta

Hey, i just had a very similiar problem to what you described. I went to start my car one day and the gauge was reading at about 10. I knew the gauge worked properly so i had my alternator and battery tested. Both were fine. So i checked the charging circuit. The problem turned out to be a loose wire at that little post next to the battery. The post with all the red wires coming off of it. Once i got that fixed the things been charging fine since. If thats not it i would check the rest of the circuit and look for a bad connection.

85 Berlinetta 2.8L V6, Auto
91 RS 5.0 TBI, Auto,

NTChrist

Perfect, that's exactly what I wanted to hear.
I'll check that red wire you described tomorrow, before my trip.
Thanks for the help guys, you may have saved me from taking the alternator on a trip to another country.

dimented24x7

iTrader: (2)

Make sure to check the battery's voltage w/ a volt meter... My batt. is fine but the gauge on my dash always registers low. Also, when you start up the car, the voltage should increase to about 14.5 volts or so. If it stays the same after startup, suspect bad alt. componets such as a bad rectifier or voltage regulator.

1MEAN92RS

I'm having this sort of problem right now, but I know for a fact that the rear bearing is going bad on the alternator cause I can hear it whining (gonna replace it and the brushes in the morning). I wouldn't think that would have any effect, but every once in a while the whining gets worse and the voltage drops for a while. Check the bearing too, just in case.

Tas

I thought I had a starter problem. It turns out the corrosion from my battery ate the wire going to the starter. Replaced the wire, good as new. Check your wires.