KLR

Hmmm... I would have bet on the voltage regulator too. That said, I would also have probably dropped the alternator off for a rebuild while I had it out to replace the regulator. If it's not bad yet, it probably will be sooner rather than later.

Have you cleaned the ground on the bell housing and the headlight grounds? I wouldn't necessarily trust the gauge in the dashboard. Have you checked the voltage at the battery with a multimeter? Perhaps you are getting appropriate output from the alternator but between corroded headlight grounds, a weak battery ground at the bellhousing, and the usual gauge ground issues you are just seeing the symptoms of a weak charging system?

sillbeer

Well, the reason I dont think its the belt is that when they slip, they squeel. this is a new belt too. I was checking the voltage with my multimeter at the battery terminals. I dont have the stock volt gauge. I spun the alt by hand it didnt have any play and the bearings were smooth and quiet. Its got a new VR but I still cant understand why the voltage is low under "X" amount of rpms, then once they crest over "X", the volts are fine for the duration of the drive regardless of rpms.

AR10

My story and I am sticking to it. Tighten the belt. Multirib belts don`t usually squeal
when loose.

sillbeer

I tightened the crap out of the belt for S&G's. no change. I'm 99% sure its an internal alternator problem

97xray

What ever came on this issue? Was it the alternator?

sillbeer

No, it ended up being the alternator light. What happens is, the charge light is in series with the field +12V circuit. So, what was happening was, blown charge bulb= no 12V to start the field in the alternator. Once the alternator got past 3000 rpm or so, it was spinning fast enough to create its own field, and thats why it would charge find after that. So, if you are having low alternator output at idle, but goes away after a certain rpm, check your battery light!