Hello All,

have a 98 c5 vert.. When I start the car the volt gauge stays at -8-10 volts, Once I bring the RPMs up to about 2000 or more then the volt gauge goes up to 13-14 volts... Is this a sign that the alternator is on its way out??


Thanks,

Ant....

 

CALL ME ASAP!! PM SENT!!!

Bill

 

I imagine Bill is saying:
DON'T TURN YOUR ALTERNATOR IN AS A CORE!

 

Big Thanks to Bill,

Called him and walked me right through some testing, Bill, Cant thank you enough....
Turns out the brushes were dirty and not making good contact... Volts go right up to 13 -14 at start up now.... Simple to do...


Thanks again Bill,

Ant....

 

LOL!! Ant,,,,,,,,, I am STOKED that the resolve for your problem was that simple! I wanted to discuss some TESTING before I made repair recommendations. I had him check several voltage parameters that made the diagnosis easier. Instead of typing a book, I had him call me.

The CLENCHER was when he revved the engine, the voltage jumped right up to charging voltage. At idle it was in the low to mid 11 volt range. We checked for loose battery & alternator connections and found NONE!

That equated to one of several issue.

1. Poor connection at the starter solenoid . Did some voltage readings and proved that he had a good main starter solenoid terminal connections..

2. Poor rotor brush connection. ( due to worn brushes OR dirty communicator).

Before I recommended that he jump right to the solenoid connections, I had him do the simple check to examine the brushes. Here is a You Tube Vid that is an excellent C5 Alternator MUST HAVE diagnosis and repair aid!!!!


He has several alternator vids that are EXCELLENT!! Check them out!

It ended up being just a case of an extremely dirty commutator to brush connection. A little clean up with some 400-600 grit wet and dry paper or fine steel wool cleaned up the communitator.


Issue resolved...

Bill