so i got my in tank fuel sending unit changed twice the 2nd one was done 2 days ago the mechanic that put them in said its fixed . so i drive and gauge drops to empty i shut the truck off and start it and it corrects itself .... i did that a couple of times .... so i call the mechanic and he said you gotta cycle the key couple of times so the pcm erases and corrects itself . i did that and it worked i fueled up and it registered .. ... i went on a 400 mi. trip today and on my way back my truck was stuck at half tank for 2 hrs im frustrated what could be the problem i just put in few gallons an hour ago and it never registered

 

The whole cycling the key is a bunch of bs Either its gonna work or not. Sounds like a connection issue

 

i took it to another diesel mechanic and they found it to be the instrument cluster see most people think its the sending unit so they keep replacing it but with my year there was an issue with the instrument cluster screwing up and reading wrong fuel level as well as on the overhead console displaying my mpg's and miles to empty so the problem is the instrument cluster and it is being sent out to be fixed if not ill have to get a new one . yea that first dude that worked on it i came to find out was a ford diesel mechanic prior to opening his own shop i figure he was just a hater

 

i changed my tank pump and didn't get the top screwed on corectly and the fload got stuck on side of tank and thats what it did....hope this helps

 

I've never had an "instrument cluster" issue, so I really don't have much to offer there. I have, however, had my entire fuel delivery system -- including the the tank, the fuel pickup and the sending unit -- out of my truck for a complete rebuild.

Yes, I agree with Rattler. The sending unit is not the greatest design the Dodge Boys ever came up with, but it is fairly straightforward. The rheostat acts as a simple voltage divider, so it's simply a matter of inputting a voltage level into the wiring harness. On the other hand, if the rheostat is really fouled -- or you have a bad connection/signal path somewhere in the wiring -- you will get an intermittent indication at the gauge.

Other than the sorry OEM lift pump that came with my truck -- which lead directly to a VP44 job -- my repair experience with the 2nd generation Ram has usually ended up being electrical in nature. A couple of years back, for example, I thought it was 47RE (transmission) rebuild time, but that ended up being an electrical issue in the end.

In short, the 2nd generation electrical system is highly ground-dependent. That is, you better keep ALL of your grounds very clean and very tight (especially at the batteries). If not, you never know what symptom you'll get. This is why many posts on many of the 2nd generation threads I've read usually include a mention about checking your battery connections and/or your grounds.

Hope this turns out to be an easy fix,
B&W