title descrbes it. some more info.
2006 mazda3 i
had a maf code, thought maybe thats what it was, replaced maf, no more code. (more power and smoother accel, but still flickering battery light.)
tested battery, passed. (basic load test, within 5 percent of rated cca)
checked wires, no obvious damage, corrosion, cleaned terminals anyway.
got a reman alt, put it on, still same story.

checked fusible link on alt to battery wire, was fine, but replaced it anyway.
new belt.
checked auto tensioner. other posts mentioned prone to failure because plastic. mine isnt plastic, maybe only plastic on 2.3?
checked forums, similar problems but in reverse to mine, so posting new.
possible that i got a bunk reman, but i also tried all the above with the original, a junkyard alt, and the reman, doeas the same exact thing with all three.
also stutters a bit, but only in second gear, and happens right as the battery light comes on.
so any ideas?


edit, forgot to mention, light does not ever come on when coasting, light throttle, or idle.

 

Alternator is controlled by the PCM.

Buy a cheap voltmeter that plugs into your cigarette lighter socket.

Engine running at idle should be 13.2 - 13.5v.

Keep a eye on it while driving.

 

I had a similar issue on a Nissan Sentra a number of years ago. It needed a new alternator. I would at least check that out (or have a shop do so) before it starts happening at lower RPMs and strands you somewhere.

 

Might I suggest you read my post a little more closely, because it says quite clearly that this happens with three different alts, the original, a lkq alt, and a reman from ac delco. And honestly what are the chances that I'd have three bad alts, even if they are remans and used. Seems highly unlikely.
In reference to your get it tested, I have done so already, with a induction load tester, pulls the full 90 amps on all three, the old one had one burned out diode, but was still working fine. Same with the other two. The issue is not with the alts, thus the post, and why it has me stumped.

 

I have a little voltmeter hooked up already. Slight dips at idle, in conjunction with a pre existing hunting issue, but I chalk that up to rpm change affecting alternator output, before the excited coils can compensate. I will keep an eye (safely of course) while driving and get back to you.

 

so this is good for a little laugh. had a shorted wire on the pigtail to the maf. replaced pigtail and soldered new wire into harness, no battery light. whoda thunk.