The workings of a GM alternator.. or not..

[Guest Anonymous]

Does anyone know what voltage the voltage sensing line needs before it stops the alternator from charging? From the indications, my alternator must have a bad diode or something as, at the altenator post its putting out about 12.5 volts which I assume is supposed to be like 14?

Reason I ask, recently the battery is'nt seeming like its staying topped up, starting harder, and the other day misfires at higer rpm and was way down on power so I take it home. I go to start it the next day and it starts but runs real rough then dies, I try to restart it and get the clicking solenoid, so put charger on it. My reasoning is, the misfiring was because its running basically like total loss after the battery voltage drops off and the alternator stops charging, once the voltage gets real low, ignition is severely effected (stock HEI which doesn't like high revs voltage wise anyway). The HEI internals/coil is the next thing to be updated, but first this alternator Does the above sound reasonable?

 

TIA,

 

Lone

[pparaska]

I remember reading that you should run the sensing wire to the positive battery terminal. This is so that the sensing wire sees the voltage of the battery, which is probably a bit lower than that of the alt output, since there'll be some resistance and voltage loss from the alt output to the battery, if anything but huge wire is used for this. The idea being if you reference the sensing wire to alt output, the battery will never fully get charged.

 

Hope that helps.

[Guest Anonymous]

Lone,

 

I normally get about 13.5 - 13.8 volts at the post or the battery when the car is running and the alternator is charging. The reason I say that is that I have the 10si on an inline 6 and it barely gets charging rpms at idle.

 

Craig

[Guest Anonymous]

Thanks guys, yeah I have the VS line going to battery post. I think I'll hunt up a alternator sounds like its a bit weak. Thanks again.

 

Lone