After my alternator went kaput on a road trip, I had it rebuilt. On the way home, things seemed fine until it got dark and I noticed that the alternator light stays on until the revs reach about 1800 rpm on the tach (although I think my tach reads a little high). I didn't notice that as long as it was light out. The voltmeter in the console reads about 13.5 V though, or about 12.5 with the headlights on. At any rate, I was able to drive home about 4 hours after dark with no issues. Still, does this indicate a bad rebuild? I hope not, because the shop that did the work is about 7 hours away.

Belt tight?

Mine does that all the time, i have to rev the engine past 2000 rpm after i start it up for the light to go out.


But, my engine isn't exactly stock ...

Fuses OK? A dirty fuse can cause some similar symptoms...

--DD

Don't know if it's the same issue, but see if this helps:

http://www.914world.com/bbs2/index.php?showtopic=237762

Typical 1 wire alternators (like used on modern cars) are "self excited".
They have to be revved up to a certain point before the field winding is fully energized.
The stock 914 alternator is externally excited by the gen light bulb.

Is your alternator stock?