Fuel Indication issues

[BusDrivr]

Hi Folks, Used 2005 Bus. The fuel gauge has never shown full, usually showed 7/8. Which was OK by me. Then one filling it showed 1/4 when full. Could not find much info in the literature left by the previous owner. Have not contacted Freightliner yet. Hoping some one has had a similar problem and a simple fix. I am worried its a sending unit and will have to drop the tank. $$$ Thanks Fred

[Grandpere]

Unfortunately I think you are right about it being the sending unit. The unit varies the amount electricity to the gauge, with a full tank, check the voltage at the fuel gauge, if it is close to 12 volts, then the sending unit is OK and the gauge is the problem, if not, then either the sending unit is bad or you have a bad wire, which means hand chasing the wire from one end to the other.

[Pigman1]

Before you drop the tank, take a look at your tank fill lines and fill line vents. They can be viewed from below at the rear of each front wheel well. The fill pipes need to be sloped down from the fill to the tank inlet. WHen it goes horizontal or even up-hill, you get an air lock during the very end of the fill process and the tank will not fill all the way. Same for the vent that goes from the tank to the fill pipe just inside the fill fitting. If you see these horizontal or sloped the wrong way, you can adjust them with a few zip ties, or by loosening the screw clamps on either end and rotating the line to achieve the correct slope/

Definitely cheaper than dropping the tank, and not too big a job for a reasonably handy guy. It solved my problem when I had similar issues as you describe.