High Voltage Issue

[pixelhaus]

my voltage has been fluctuating pretty dramatically which led me to believe it was a faulty voltage regulator. I replaced the regulator and the brushes but still have the problem. I tested the charging system and it's definitely reading high. 16.3+ under load.

any ideas what could be causing the spikes? ground issue?

thanks

 

[Briank]

16 is high, how are you measuring it?

 

[EdinKali]

Are you relying on the dash gauge for that reading or are you testing at the battery terminals with a voltmeter? If you are relying on the dash gauge, use a voltmeter instead. If you were using a voltmeter, I would check all your grounds. If they all check out you might want to use the manual and an ohm meter to check out the alternator internals.

 

[pixelhaus]

I had the charging sytem tested at Autozone.
everything passed except for the alternator which read 16.3+ (i know it was at least 16.3, possibly more)

is it possible that the alternator still could be the culprit even if i did replace the volt regulator?

 

[EdinKali]

Depending on the manufacturer some recommend replacing both the regulator and alternator at the same time. It is possible that a problem with the alternator caused the voltage regulator to fail. If the problem is still there when you replace the regulator it is possible that the new regulator will get damaged as well.

Having said that, in the past I have replaced just the regulator on other vehicles and been just fine but each situation is different.

If you don't have the skills to check this stuff yourself, take it to a reputable shop(ie. not PepBoys/Autozone etc.) and have them check it out.

 

[DrDave]

I would try two things. First I would confirm your voltage readings with a good meter like a Fluke. If you actually are charging at 16.3 volts that speaks to the regulator being bad. A bad diode in the rectifier bridge will cause low voltage. The regulator is the only component capable of having a failure mode that will cause high voltage.

I use Regitar brand regulators for the Acura Legend alternators that I rebuild. What brand were you able to buy?

Voltage spikes can come from the B+ (output) lead being momentarily interupted. Opening the output circuit of a charging alternator will overvolt the rectifier. It could take out the regulator as well. Check for a lose connection at the alternator/starter/battery/fuse box.

Sounds like an interesting problem. I will check back frequently to see your progress. I would be glad to help you. I have overhauled ~15 of these style alternators.

Dave

 

[angus]

WOW , I'd like to have 16 volts , wanna trade alternators?

 

[grybrd]

WOW , I'd like to have 16 volts , wanna trade alternators?

Now don't get greedy!

16 Volts will fry your battery and who knows what all else in your electrical systems.

Are you sure you want that?

 

[pixelhaus]

thanks for the responses.

I'm not sure what brand the replacement regulator was. Could be a cheap one. I may just get a complete alternator and see if that works.

i'll post results.

thanks again

 

[pixelhaus]

fixed the problem.
replaced the entire alternator and the problem was fixed.
so, either the voltage regulator I purchased was bad, or it was some other part of the alternator.

glad to be running again!