I have an 84 gl wagon and when I drive it the volts go way up when the rpms are high.

if there is such a thing as a regulator could that be it?

I also took out the alternator a few weeks ago and thought it could be the tension of the belt?

anyone know what it could be?

I was wrong before on which models had an external voltage regulator and which have an internal VR, but I believe that yours is an EA81 which should have an VR external to the alternator.

 

Either way, yes, there is a VR that could go bad.

Your alternator is toast!!!

 

Trust me on this one

 

How do I know this....

EA81's after 1982?? I believe had an internal regulator, and used an alternator identical to an EA82.

 

Just like Sweet82 said, your alternator is toast.