My truck is a 2001 2500 ram with the 24 valve. When I first start my truck up in the morning I can see the alternator kicking on and off back and forth. It gets down to about 10 volts and then goes back up to 14. It’s so bad I can watch my headlights dim and get brighter, I am wondering if this is normal operation or not? I also have a problem with my truck shutting off at idle out of nowhere, wondering if the injection pump is getting low voltage every now and then causing it to shut the truck off. Then the truck starts right back up no problem. I have done the AC noise mod and replaced the alternator about a month ago. If the pcm controls the alternator cut in/ cut out I wonder if it was harmed from the AC voltage before I fixed that? Any help would be appreciated 

What do you have for fuel pressure 

54 minutes ago, SSIRMAN said:

When I first start my truck up in the morning I can see the alternator kicking on and off back and forth. It gets down to about 10 volts and then goes back up to 14. It’s so bad I can watch my headlights dim and get brighter, I am wondering if this is normal operation or not? 

If your grid heaters are comming on at first start up that would be normal. When the heaters kick off is when you see your voltage rise back up to 14. and headlights back to normal.

The up and down voltage is from the grid heaters running. The cut in and in a cycle can draw about 90amps each. How cool is it out your way? I beleieve they kick in at below 60* IIRC.

1 hour ago, Royal Squire said:

What do you have for fuel pressure 

Not sure about fuel pressure because whoever installed the fass, removed the Shrader valve and it has just a straight line going to it. 

 

51 minutes ago, dripley said:

The up and down voltage is from the grid heaters running. The cut in and in a cycle can draw about 90amps each. How cool is it out your way? I beleieve they kick in at below 60* IIRC.

That makes sense, but when it dims down in the mornings sometimes it dies and I have to keep on the throttle til it’s warmed up. Lately it’s been pretty cold but it’s done it before when it was like 70

3 hours ago, SSIRMAN said:

Not sure about fuel pressure because whoever installed the fass, removed the Shrader valve and it has just a straight line going to it. 

 

That makes sense, but when it dims down in the mornings sometimes it dies and I have to keep on the throttle til it’s warmed up. Lately it’s been pretty cold but it’s done it before when it was like 70

#1 you need a guel pressure gauge. You really need to keep tabs on it. You dont want to see less the 14 psi at WOT. It will keep your VP happy and hopefully live a long. Mine has 239k on it now with good fuel pressure and 2 stroke oil in the fuel.

 

You could disconnect the grid heaters at the battery and see if that soves the stalling problem. If it stops the stalling some one with more electrical experience would have help with that. I suupose you could pull enough voltage away to cause the engine shut down. But again that is a bit over my head. 

2 minutes ago, dripley said:

I suupose you could pull enough voltage away to cause the engine shut down. But again that is a bit over my head.

 

Secret. The minimum voltage that ISB Cummins will run is 8.00 Volts. 

Yes, like Dripley says you should only use your grid heaters only when needed. IBMobile is designing a switch so you can control them and help save the alternator diodes. Mounted in the cab it will be set up so it won't throw error codes.

     For now most of us have them disconnected at the drivers side battery until absolutely necessary.