Hi so I can't figure out what's wrong with my truck it's the 5.9 Magnum 2001 2500. My voltage doesn't seem to bad, when nothing is on voltage is at 12 when ignition is on it bumps up to 12.4 then 14.4 with the engine on but the voltage seems to raise as I hit the gas . When I was moving my truck backing it into my parking spot it started to vibrate and almost shut down until I let off the gas. I'm assuming it's the alternator because there are no warning lights on but I'm not exactly sure wouldn't the battery light be on? I was thinking maybe a connection issue? I really think it's the alternator but the rpms lower down to about 3-400 when I let off the gas at idle and I didn't think that would have to do with the alternator. This all started today. Mileage is 165000 which is when most factory alternators will become faulty after that period of time I'm guessing.

 

When you hit the gas the voltage will go up some. The almost stalling sounds like a sensor issue (IAC or TPS)

 

Alright thank you, would a light be on for either of those issues or no?

 

If your alternator is over charging yes, the bad IAC or TPS sometimes yes sometimes no

 

Okay, got it. I haven't gotten any sort of warning lights on so I guess I'll get the alternator switched out first. Wanted to get it replaced anyway. Then have the sensors checked

 

I THINK you can use a multimeter to check them but I'm not sure on that would have to reference the FSM

 

Your alternator is working as it should. It doesn't need to be replaced.

You have a sensor issue. Test the TPS first. It should be less than one volt at closed throttle, and greater than 3.5 at wide open throttle. It should progress smoothly between those values. (an analog meter is required for this test, digital meter won't tell you anything useful.)

 

Vibrating has nothing to do with the alternator. My project Jeep w/5.2 Magnum engine has gutted alternator, it doesn't have rectifier or brushes because they are toast. It's like that so I can run the engine to the operating temp every once in a while, and it purrs like a kitten. Like HeyYou said, you have sensor problem.

 

Alright thanks for the information, I picked up a Throttle position sensor since its not to expensive. Gonna replace it tommorow, got a new alternator anyway since I have a feeling it's not gonna last much longer. Also gonna pick up the Crankshaft sensor as well. Gonna get all 3 for $200 not a bad deal.

 

Aftermarket crank sensor will cause more problems than it solves. For critical sensors of that nature, you REALLY need to get genuine mopar sensors.