my alternator died about a month ago, but when I pulled it out the first time it tested good so I threw it back in with a new belt and it seemed to work. after about 150 miles, it started intermittently going out, so I decided to actually replace it.

I bought a reman Autolite alternator from kragen, and jut put it in. when I first turn it on, it provides about 14.6v which fairly rapidly increases to 15.8v. This seems WAY too high to me, and likely enough to burn something up. It also seems to drop the idle a decent bit lower than usual, ie 1200 cold when it's normally 1500 (and when it first starts up and is still lower voltage it's 1500, which then drops as the voltage increases).

So, did I get a defective alternator? I wish it wasn't so much of a PITA to replace it.

this is on a 1990 DA if it matters.

 

i had this problem, specially when i reved up everything got brighter..
had something to do with the ecu regulating the voltage thats all i know... never actually fixed the problem i sold the car before it was fixed.. but a new ecu i heard solved the problem.

 

Well the voltage is the same at 1200rpm (what it's idling at once it's up to 15.8v, maybe 30s after it starts) as at 3000rpm, so it doesn't really get brighter when it's revved up.

 

Check the voltage regulator. The voltage generated from the alternator is never directly fed back to the battery, it is generally the voltage regulator that limits the voltage to the battery/electrical system.

 

the vreg is in the alternator, so it was replaced when I replaced the alt. I agree that it's the vreg that seems to be the problem, not the alternator itself - I was just wondering if there was anything else that caused vreg issues.