Major voltage spike causing issues
Thread Starter
Pro
Joined: Mar 2016
Posts: 562
Likes: 66
Major voltage spike causing issues
We recently put a new motor in the car had a low voltage issue initially. The shop decided to install a smaller pulley to get back the voltage since we were low while running prospeed fans and a trans cooler/fan. Mechman 170 alternator (2017)
Heres the issue right now:
At cold start within a few seconds the voltage fluctuates from 14.1-14.7....then spikes to nearly 18 and throws a bunch of codes. It even opens the NPP valves and wont close until the voltage randomly drops back down.
It also does this while driving randomly. I need to finish the break in miles but dont want to drive it like this bc of fear burning up something when it spikes the voltage.
I know the alternator is older so should I send it in for a rebuild or should we try going back to the original pulley? I also had a bad battery that I recently changed so who knows if that caused the initial issue making them want to change pullies...
Heres the issue right now:
At cold start within a few seconds the voltage fluctuates from 14.1-14.7....then spikes to nearly 18 and throws a bunch of codes. It even opens the NPP valves and wont close until the voltage randomly drops back down.
It also does this while driving randomly. I need to finish the break in miles but dont want to drive it like this bc of fear burning up something when it spikes the voltage.
I know the alternator is older so should I send it in for a rebuild or should we try going back to the original pulley? I also had a bad battery that I recently changed so who knows if that caused the initial issue making them want to change pullies...
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,631
Would pull voltage regulator off alternator to clean its contacts and mounting points on the alternator , make sure that the bolts are tight when reinstalled, and it does not solve the problem, then voltage regulator needs to be replaced. Hence with high voltage, everything on the AC side is fine, and it the voltage regulator that is the problem itself.
Basic tear down of OEM Valeo unit, with the billet not much different over all
https://www.corvetteforum.com/forums...nator-fix.html
If pulling an alternator apart is not your cup of tea, then send the unit back to be rebuilt, which will include a new voltage regulator as well.
Basic tear down of OEM Valeo unit, with the billet not much different over all
https://www.corvetteforum.com/forums...nator-fix.html
If pulling an alternator apart is not your cup of tea, then send the unit back to be rebuilt, which will include a new voltage regulator as well.
