You will probably find that your sending unit is has bad corrosion and that the connection from the wire to the board or the wiper to float has a bad connection. Ceramic board with carbon tracks on my sender, no wire on these things now. Had to clean and crimp the fitting once and replaced the whole sending unit the second time.
Went for a while just filling tank up at the end of the day and you will not run out of fuel. You will have to take hood off to remove sending unit.
As long as the tank is just short of being over full the L3130 will self bleed the filter housing and the line to the injection pump will bleed when the top bleeder screw is opened.
Wonderful crap we have for diesel, all diesel in Oregon is B5 and they have B20 for cars now.