rb25 Voltage problem

[bkos90]

Alright, can anyone help me figure this out.
I have a s13 with rb25det and my voltage skyrockets from 14 to past 15.5 when i accelerate or brake. Is it the alternator voltage regulator? or something else?
Anyone had this problem before
thanks in advance

[Infinitiguy19]

I would agree with the alternator voltage regulator being the issue.

[Krazykouki]

Make sure that the gray connector is connected and sending the proper voltage to the alternator. If the 12v wire is not hooked up via the gray connector it will do the exact thing you describe.

[bkos90]

Thanks a lot for the help. i will check it out if the gray plug is in place and if the wires are ok. if not ill just have the alternator fixed

[bkos90]

ok, so i took the alternator to get checked and the guy told me that its working good.
The car still does the same thing.
i recently installed a voltage gauge in the car, as the ecu says 15.5v the gauge that is connected inside the car to the ACC circuit is showing 11.5v, The tachometer starts to spike and the lights inside the car begin to dim (at night time) . this only happens on acceleration and braking, when the car is idling its fine.
I tried to troubleshoot a little and disconnected the battery from the car and took it for a drive, it goes fine for a few seconds to a minute and then just goes completely dead.

Anyone know what this can be? or how to troubleshoot it further? i am really clueless as of now. anything i tried didnt work

[RustspecS13]

Is the ground on the alt connected? The small one that hooks to the 8mm bolt?

I would look for a starter/alternator rebuild shop around you and them do a through test on it. It might be failing when its under a load in the car.

Or try taking it to advance auto, they should have a good in car tester that should be a little more through then a bench test.

Also take a look at the wiring that connects to the alt, make sure its not shorting out on each other and causing problems.

~Alex