When I start my car and let it sit in idle at like 850RPM my battery reads a little over 13v at the terminals. My gauge reads like 11, it's in the middle between the 13 and 8 marks. Why is this? It used to be between 13 and 18 and now it sits low. Can the gauge be bad? How can I tell the alternator is running?

 

If the car starts right up and idles, and the battery doesn't need frequent re-charging, then the alternator is working properly. However, that is definitely a pretty low reading. How old is the alternator? Do you have an aftermarket volt gauge?

Am curious.... start the car, then disconnect the battery. Did the voltage go back up on the gauge? If it did, put it in gear, then turn on you're wipers. What does it read now? If it's still low, then it's prolly a slowly but surely failing alternator.

 

Stock 87 gauge cluster. Is it possible to damage a battery gauge? does it have a fuse?

 

There should be a fuse in the fusebox marked 'gauges' for it. I never had a damaged volt gauge, so I'm not sure what can happen to them over time....

You're best bet is to install a gauge pod (if you already don't have one), and get you're hands on an aftermarket 2" voltometer gauge. This will give you a better, and more accurate reading.

 

Umm, aren't voltage spikes bad?

 

'Voltage Spikes'???? 'Removing' the battery cables from a running engine won't cause that severe of a spike. Only when you 're-connect' the battery cables... in which the engine should be shut down.

Plus, he's not running an ECM or TPI, so what's the worst that can happen? A blown fuse, or fusible link?

 

Smoking the Alt voltage regulator or one of the diodes would be un-cool !!!

Adding another volt gage to your cockpit would also be dumb.(Unless you want to look like a rye_cer)

I would bet your gage is OK. You probobly have a bad connection in the wiring causing the supply voltage to drop down, or the "ground" supply to drift up above zero volts. The gage displays the voltage differance between the two.

Someone on this board had a problem with the connections on the dash circut board where the volt meter mounts.

Do you have a DVM for troubleshooting???