I have an odd issue with the gas gauge. It shows full when full but it shows empty with 1/4 tank left. I know it still has gas in the tank because my build sheet shows a 34 gallon tank from the factory (confrmed by looking at the info on the tank itself) and if I fill it up when the gas light comes on at "E" it will only take about 26 gallons to fill.
Are there 2 different sending units for the 2 different gas tanks, 26 gallon and 34 gallon?
Is there a gauge calibration I can perform? I am not sure about that idea because of the low fuel light?
I am asking about this issue because after searching the forums it seems like the common sending unit issue is that it shows fuel when there is actually none. The complete opposite problem of what I am seeing.
Is it as simple as changing the sending unit?

 

BUMP.....
Surely somebody out there must have some info??

 

Well I have not been having to much luck helping people lately but as far as I know there are two different pumps for the diff size tanks. As for the sending unit its part of the fuel pump and can't be changed by itself. I am sure someone else will chime in about this.

 

That was kinda sorta planned.... When the gauge reads empty, there is still a few gallons in there as a "reserve"... so you can get to the next gas station. Hopefully..... Also, I have yet to see a gas gauge that is actually ACCURATE..... Another consideration is, while your tank may have 34 gallon capacity, not all of it is useful. When the truck stops running, due to fuel starvation, there will still be a couple gallons in the tank.

 

Here's a pic of the pump and the sending unit, all one piece. When I got my new pump last week dodge asked me 3 time what size tank I had. So are you saying they are all the same? cause one was $100 cheaper than the other one.

 

They all have the same issues...... But, I don't know if there are differences between pumps for the different size tanks. Not sure what they did to expand the capacity. If they just made the tank longer, one would think the same pump would work in any tank......

Of course, the auto manufacturers have been known to do some pretty silly stuff on occasion......

 

The jist I got was one was deeper than the other, by how much I have no idea, and that as you said would leed to different readings on the gauge. I think I might make some phone calls.

 

yea the 34 gallon tank is 1 inch deeper....and that 1 inch by the length of the tank is about 3 gallons, and the fuel pump does not set on the base of the tank, so there will be gas it is not sucking.