alternator discharging
 

Just had motor r/r. Not charging...so I put in a new alt...hooked up exactly as original. Now it shows 12v at idle and 10v at hi idle....what gives.

Oh...454 magnum 97

Check water in your Batt.'s sounds like you got a cell down.

fixx
 

+1 or just a bad battery..

I have a 88 Formula with a 454 Mag and it started doing the same thing one day. It drops to 10V at 5K but will pull 12V until 3K before it starts falling off at the higher Voltage does the same on each battery or on both.

Tried 4 dif batts...same story.

Bodi...so what did you do....

fixx
 

ok did you replace the belt? could be slipping..

Possible...but would a loose belt make the gauge go down as the rpms go up?

Gauge drops 2volts

Possible...but would a loose belt make the gauge go down as the rpms go up?

Gauge drops 2volts

Whoops...sorry for the show post

fixx
 

possibly,,when a vbelt wares usually it will drop low into the pully making contact with the bottom of the pully and it wont make contact with the sides,then it will slip and discharge when the rpms go up and show low voltage when the ignition demands more voltage for the higher rpm and will make the belt slip more..

if its glazed (sides are shiny) replace it..

Are you checking voltage right at the battery with a multimeter or are you going by the voltage guage on dash ?

If good at the battery, you are all set charging wise. However this means you are having a guage or voltage drop to the guage or guage panel problem.

Turns out the rebuilt alternator I got from the local shop was bad. I found a place in TN that has new units for about half of what I paid for the rebuilt unit.

Thanks for all the help fellas.