2000 Ford F-250 fuel gauge reads 3/4 full when I fill the tank all the way. Replaced the fuel pump that had a new sending unit attached.. still reads 3/4 at full. What am I missing to fix this problem? Thanks for any help!

 

When the tank is full, the float on the sending unit should be at the upper limit of travel of the wiper on the resistor of the sending unit. At this time it is not and the float arm will need to be adjusted to put it there when full. The tank will need to be dropped so the module assy can be lifted out and the rod adjusted . Can we ask who installed the assy?

 

yes I installed it just like I have a bunch of times. Odd that the float would be out of sync on the OEM pump as well as the new one? What exactly needs to be done to adjust it? I also heard this could be a ground problem I figured that is more likely considering it did the exact same thing on the pump before it

 

This is something you might try. You will need to remove the fuel pump module assy to do this.

With the key on and the fuel pump module plugged in and in your hand, have someone watch the gauge in the dash while you lift the float. When you get to the near end of the travel lifting the float , the gauge should go to the full mark. Let us know what you find there.

 

OK so if it does show full what do I do? And if it doesn’t show full what do I do? I’d like to know what I need to do as I’m going to try and take it apart this week sometime and don’t have to wait for a reply for the next step after I take it out of the tank

 

Suggest you look inside the tank and make sure nothing is preventing the float from coming all the way up when full.
If you cannot find anything , think about this, As the level in the tank rises, so does the float. If the level is at the full mark that is when the float should be registering full. All you need to do is make sue the gauge reads full when you lift the float to tht approx fuel level. If not ,you can bend the float arm so the gauge reads full at that liquid level inside the tank.
If for instance at the liquid level of full and the gauge reads only 3/4 , bend the long float arm down so it will get to the full position sooner..

 

If you can get to the sending unit connector, pull it off. With an open circuit your gauge should peg out as far as possible past full. That will atleast rule out the gauge itself in the dash cluster. I doubt you have two sending units having the same issue.

 

The float arm and setting are critical.
I have seen some installations where the installer was somewhat crude and bent the arm on installation.