Hmmm, so the exciter wire (The one on the top?) Tells the voltage regulator the amount of current voltage to output?

 

Not how much voltage by number, the alternator only puts out a certain amount of volts. The exciter wire is connected to the cars main power source, and tells the voltage regulator when to kick on and off (like a switch) based on the power needs or draw of the electrical system.

 

Thanks for clearing it up, that's also something the O/P can mess with, computers/electricals in these cars are pretty fragile

 

the exciter wire should read the same voltage as the system with the ignition swicth in the on position. it just tells the alternator if the ignition is on so it can start working. the voltage regulator in the alternator regulates the volts and amps the alternator will put out. now if the exciter wire is failing at high rpms then that would explain the problem.

 

thanks for all the help...here's where I stand.

Going to put the newer alternator (that tested fine at the store) back in the car tonite.

This alternator was the one that had the symptom of losing voltage as RPM's increased. Last time I put it back in it only read 12 volts...

I thought the 'exciter wire' (little wiring running from the harness that plugs into the alternator) has used to read voltage and the alternator was internally regulated.

I'll be sure to triple check the wiring running from the alternator to the battery.

Here is another thought...I removed my underdrive pulley kit and went back to stock pulley system. Since then I have had issues with squeaky/squeeling belts...so far 2 belts.

Is it possible that my tensioner is worn and is not applying enough tension...thus causing the noisy belts and maybe slipping on the alternator pulley, thus causing my voltage issues?

 

Not sure about the electrical issues caused by a weak tensioner, but 2 weeks ago I replaced the tensioner and I can honestly tell you, yes it will get rid of the squeak from the worn tensioner. Trust me, I know how annoying it can be

 

well that could change everything. a slipping belt will cause the issues you are having. not all belts squeal when they slip. at low rpms the pressure ono the pulleys will not be high, as you increase the rpms the amps will also increase and put more pressure on the belt.

 

And still again.....when you tested your alternator output voltage when in the car, was that at the alternator, or at the battery?

 

when i measure the voltage, it was the same at the battery and the alternator...which lead me to believe the alternator was bad...it was reading around 11.4v...same as on the gauge cluster...used a multimeter. Then i took it to get load tested and it tested good.

So i was thinking it was a grounding issue...but I think tomorrow I'm going to pick up a tensioner anyways...and also check the grounds that crabby mention.

I didn't see any nick, cuts, or corrosion on the wires. I rebuilt this a while ago and replaced anything that didn't look up to par...however, i didn't replace the 'exciter' wire, but it looks good (clean connector and wire has no cuts or corrosion).

 

...And the ground wire on the alternator that I mentioned. Did you check to see how much voltage you have at the exciter wire, at the alternator plug?