My 1993 Buick Regal with 3.8L motor has a charging issue. The voltage gauge on the dash fluctuates up and down and the lights are dimming accordingly.

I put in a new alternator and battery this morning and there was NO change. Still having the same problem. It happens whether I'm stopped in my driveway or driving on the road. Seems that there is no pattern. I was sure the new alternator would solve the problem.

Any idea?

Thanks, Ron

There should be a wire that clips into the alternator...usually its a white or black plastic clip. One of the wires on there is your primary charge wire and more than likely its really old and as such it has cracked and heat damaged...when this happened the copper wire on the inside gets very brittle and carries way to much resistance.

Check those smaller wires that attach to the alternator like i said and inspect them for damage/fatigue/cracks/brittleness etc. Replace any pieces of wire as necessary.

Well, it seems that it is the tensioner that is causing my problems. After hours of diagnosis and a new alternator and new battery I hope this problem is now behind me. I'll know on Thursday when the new tensioner gets installed. Sometimes I really hate old cars.
Also, I don't find the gas mileage on this 3.8 motor to be very good. I can't reach 30mpg on the hwy even. My '93 Chev Lumina gets better mileage with the 3.1L motor and about the same cliks on the odometer...150k. I think I get 5mpg better overeall with the Chev and both cars are '93's.

but 1 car is .7 bigger and weighs more with cast heads.

Yup, new tensioner was the solution. Now car is 100%.
Anyone interested in buying it?

no way....too hard on gas :):)