My 93 w350 doesn't charge unless you rev it up over 2000 rpm.Let it idle down below that and it quits charging. Installed a reman Chrysler alt. and it does the same thing. Any suggestions? Are one of the small wires on the back supposed to be hot with the key on to energize it?

 

take the reman part back its not the prob voltage reg sounds to be the prob

 

make sure the regulator isgrounded well, our alt charges by ground.

 

'92 and '93 trucks have the regulator built into the PCM, guys.

Sounds like a crank sensor problem. The PCM uses the crank signal to tell it when the engine is running. If the PCM doesn't think the engine is running, it does not energize the charging circuit.

The crank sensor is on the front of the motor right above the crank damper. Check the wiring, and check the gap between the damper and sensor. The gap should be 0.050", use a brass feeler.

 

wannadiesel,You hit the nail on the head,cruddy connection at crank sensor plug. Many thanks!