I have noticed that my fuel gauge barely drops below a 1/4 tank and It seems to be starting to suck air as if it were empty. When I fill it up it goes right back to full and will drop as the fuel is burned. Anybody here of this? It's a 90 D250 and all the other gauges seem to work, also, what is the easiest way to get the tank capacity?

 

Sounds like you might have a leak in one of the internal hoses in the tank. There is a write up on here on DTR (I think it in the sticky) about converting to a bigger fuel line. It shows some really good pics of the in-tank fuel sender/filter set up.

 

I think the tank holds 28 gallons or so. The gauge is calibrated low on my trucks. At empty they usually have 5-6 gallons left in them.

How much do you put in to fill the tank at 1/4 tank?

 

Mine is really goofy too. Mine likes to go fast between 3/4- 1/4. Then hang at 1/4 for awhile. I use my trip meter as a supplement up to my gauge.

 

All our dodges have the 30 gallon fuel tank. I've had mine out enough times to confrim this.

When my gauge gets to E, and the light comes on, when I go to fill it back up, it takes 24 gallons, which left 6 gallons in the tank.

Each time I've had it out, I emptied it and inspected the inner of the tank for debris, etc. I then put the tank back in, and filled it with a 5 gallon Jerry can of diesel. Immediately, I went to the fuel station and put the remaining 25 gallons in.

If you think you're going below the 6 gallon threshold that chrysler designed into the "reserve" to prevent knuckleheads from running out, then it's time to replace the fuel sending unit in the tank. I've purchased both of mine (two trucks) from chrysler, and they weren't extremely expensive. ~$50 or so, plus the new tank seal, and a new filler neck seal and you're good to go. Last time I checked, all were still avail from dodge.

 

we have a 30 gallon tank. i just replaced my fuel sending unit this winter with an NOS dodge unit. my low fuel light comes on at 22 gallons. i'm on the last line "E" at 24 gallons. i've never put more than 25 gallons in my tank at a time. just my .02

 

Last I filled at 1/4 tank it took about 20 gallons,it seems like I've run it longer at a 1/4 this time and I'm going to fill it and see if it takes any more

 

What is the farthest you dare to go with city mileage?

 

The shape of the tank is what makes the gauge seem to act goofy. the gauge only knows where the fuel level is. It can't compensate for more or less fuel due to the tank being at the top or bottom.

 

That's about how these gauges go. That's the fudge factor designed in so you don't run out of fuel.

 

My fuel gauge is going haywire -- all over the map. But the Low Fuel light still appears to function properly -- coming on when about 6 gallons remains in the tank. Does not the fuel sending unit in the tank control both the fuel gauge and the Low Fuel light? What else would cause this issue? I've been burning B100 biodiesel recently if that matters...

TIA.