Fuel guage
 

Fuel gauge in my 71 swb worked fine, installed a new poly tank in the rear, ran a new wire to fuel gauge, have tank filled up but only shows 1/4 on fuel guage. What have i done wrong. Thanks

Same thing happened to me. The float had a pin hole in it and wouldn't float to show a full tank. Only got to 1/4.

I thought that is why you buy brand new, so you don't have these kind of problems. i guess i will be pulling the bed off agian.

Where did you hook the wire? It also needs a ground off of the sender. Need more info

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Andy
71's Are for ever!!! or 67,68,69,70,72 http://geocities.com/chevy71tpi/main.html

If it wasn't grounded, it would read past full, wouldn't it?

Is your old gauge still hooked up and somehow altering the reading? Disconnect your new one and see if the gauge goes to past full (open circuit). Then short it to ground and see if it goes to past empty (short circuit). If both of those tests work, maybe your sender is bad, or maybe the sender doesn't have the right resistance range to work with your gauge.

Ground appears to be good off tank, and it did read past full until i hooked it up to guage. When i hooked up to guage it went down to almost empty, filled tank up and went up to 1/4 and hasn't moved since

Sounds like either a sunk float or something binding and not letting it come to the top.
Either that, or a sending unit that doesn't match your gauge. Contact the vendor and ask them what the resistance reading of the sender should be at full and empty. Compare that to factory spec, and also to what yours is doing. Just pull the wire and ohm from the wire to ground.
I'm betting you'll end up pulling the tank and sender and either rotating the sender 60 degrees, or bending the arm because it's dragging on the side of the tank. Just a hunch...