tmajikman

I just did a 3g upgrade 200 amp alt. Works great after 1500 rpm's. At idle it goes don to the white bar above the red bar. I thought there was something that energizes the alternator to stay charging to around 14 volts. Is it normal for an 87 GT to do this. Like I said if I am at 1500 rpm and driving down the road, it charges in the middle. No under drive pullies, I did get a new pullie with the new alt. seems like the same size, and the belt does not slip. What could it be if this is not normal. Btw the battery had a rough life when I eas using my old factory alt. Filled it with water and seems to hold a charge just fine.

tmajikman

Anybody else's stang do this. Thanks

nyfreakinrican7

I just put my 130 amp in and it stays in the middle at idle and while driving. I put the original pulley on mine. It reads like 13.8 volts

tmajikman

I will see if the pullies are different. Maybe the battery is in need of replacement, it would be a free one.

AdderMk2

should have just bought a 130 from me

945LSTANG

for how much??

AdderMk2

$45 shipped

tmajikman

I found a fix for my issue, I raised the idle up 100 rpms and now I amputting out 13-13.5 at idle. It is the only thing I could think of, I just did not like it going to close to the red at idle.