Hey guys, I own a 91 G20 Super Van 5.7 and the fuel level gauge only stops working at half of a tank. When I fill up the van, the gauge goes all the way to full but once the needle reaches half a tank it doesn't move any further. I was wondering if it was the fuel pump sending unit or the fuel gauge itself. I'm about to go on a cross country trip in 10 days and would like to have the problem fixed before then. Thanks for the help!

 

The resistor in the sending unit might be broke or the float is waterlogged. Either way the sending unit is part of the pump, so you have to replace it all. Time to reset the trip odometer at every fill up so you can go by fuel range.

 

So do you think replacing the entire pump assembly would fix the problem? I just don't want to spend $150 for a new pump only to find out it's something else.

 

I doubt its the gauge. The gauge is a variable ground. The sending unit has a contact that moves along a wore resistor. The more resistance....lower reading, the less resistance...full tank. If you have half to full working, then the sending unit could have varnish impeding the continuity of the contact as it moves along the resistor. If you took out the unit and tried to clean it with carb cleaner maybe it would fix it. But I don't know if that part is servicable. You may not be able to get into it to clean it.
Hard to say.
If you want to test the siring and the gauge, just remove the wore from the sending unit, and tap it on a ground. The gauge should peg to full as you tap.