With the engine running and no accesories except for my stereo I'm reading 16 V ideling at 1000 RPM. If I turn the fan on ( manual fan switch ) it dips to about 12.5-13 V. Then add the running lights and it reads about 11. Now another thing is I can be driving and when I hit the break pedal the voltage gauge, the oil pressure gauge and temperature gauge all go down a notch and when you let off the break the go back, so it looks like they tick back and forth a small amount if you pump the breaks on and off. Is my alternator going or is the Voltage gauge not accurate at all?

Could be the alt. but I would place a better bet on wiring, grounds, etc.

Check the gauge compared to a volt meter to see how it compares. Need to check at the same place otherwise the reading could vary some.

My 88 does dance the volt meter some with the turn signals and fan but not to bad.

It can also be the voltage regulator responding slow to voltage changes. My 96 GP dips when you hit the brakes. You can even see the headlights dip and return to normal for less than a sec.

[This message has been edited by Dodgerunner (edited 06-19-2006).]

quote Originally posted by olaf_fiero27: ... I'm reading 16 V ideling at 1000 RPM.

Something's definitely wrong! 16 volts is too high ... even for a cold winter day.

Step 1 is to get a voltmeter and measure the voltage at the battery to confirm (or contradict) the readings you're getting on the stock voltmeter. Expect to see less voltage variation with changes in electrical load when measuring at the battery, but otherwise you should measure between 13 and 14 volts at the battery terminals from idle to redline.

I would not be surprised if your alternator, regulator, and/or battery are failing ... or have already failed. Once you get the voltage within the proper range, then you can begin looking for poor power and/or ground connections.

[This message has been edited by Marvin McInnis (edited 06-21-2006).]

quote Originally posted by olaf_fiero27: Is my alternator going or is the Voltage gauge not accurate at all?

Check everything above mentioned, but Fieros are notorious for inacurate gauges, especially the volt gauge. If the alt is going , you`ll know in short order as it keeps your battery charged.

Have to watch out for overcharging as well though, it will kill you battery but good. You'll still be able to easily jump the car, but it will die very quickly when not running.

Second thought, sounds like your battery is already dying and not properly charging, causing the alternator to work overtime to attempt to charge it. i would replace the battery after confirming the voltage reading.

The drastically changing voltages with power use may be the result of running your car primarily on the alternator, since the battery reserve is failing.

[This message has been edited by Xanth (edited 06-20-2006).]

In the last few days I had the motor apart and upon reassembley I forgot to add my engine ground. Well I put it back on this morning and then voltage gauge reads about 16 at idle with no acc. on. And with the fan and running lights on it was reading about 13.5 V.

Edit gauge is reading about 15 V no matter what. With no accesories on or with all of them on I'm getting a reading of about 14-15V.

Quick trip to an good auto parts store. They can 'Load Test' your battery. If you've been running 16 Volts to it, for any real length of time, you may have 'cooked off' your batery. They can swap out your battery and check your alternator for Voltage and Amperage, to determine if it's bad as well. At the same time you can compair you're voltage readings with theirs, 16 volts sounds way too high, something's not quite right.

I get 16volts at start but it goes down to 13v after a minute or 2, but at night when I have the lights, fan, stereo (decent volume) it sits at 13v but if I crank the stereo the guage moves with the sound also the same if I use my turn signal. But I can put a large drain on my charging system real fast and it automaticly jumps to 16v till it catches up.

Well like I said after adding the engine ground I don't see 16 V anymore. It's 15 at start up and about 13-14 with all accesories on.

Please stop reading the volt meter in the car. Get a hand held volt meter, or barrow one, and get some reading that we know are good numbers. Do not use your car volt meter to trouble shoot this problem.

Jack

Where am I measuring from? Battery posts?

quote Originally posted by olaf_fiero27: Car Idleing with no accesories on is ready 14.2 Volts AT THE BATTERY. With all the accesories on Im getting a reading of 14.0 Volts AT THE BATTERY. Is that where I'm suppose to measure from?

Yes!!! (bangs head in frustration)

quote Originally posted by Marvin McInnis: Step 1 is to get a voltmeter and measure the voltage at the battery .... (emphasis present in the original post)

14.0 to 14.2 volts at the battery (with the engine running) is within the "normal" range.

[This message has been edited by Marvin McInnis (edited 06-22-2006).]