inaccurate gas gauge reading

[tach]

My gas gauge has been on a 1/2 tank for a while and I know for a fact that was not a right reading. So I take it to the gas station to fill it up I put in 10 dollars, gas is $1.70. When I got $5 worth the tank was overflowing (about 3 gals) when i started it up again my gauge still reads 1/2 tank.

I put in a new tank a while ago could it be the fuel sending unit?
I wasnt to sure I put it in right, might have rotated it to much?
I didnt know there was anything wrong all the gauges didnt work when I put the tank in, I noticed this after I replaced the wiring.

 

[slapper]

There's a tab on the base of the sending unit so as it cannot be rotated in the mounting flange.
Remove the wire from the sending unit,turn key on, ensure fuel gauge reads empty, ground it, ensure fuel gauge moves to full.
If this checks okay, drain fuel tank, remove sending unit and check for freedom of movement through out full range of movement.
Attach wire to sending unit, turn on key, move float throughout full range of movement, gauge should respond smoothly and accordingly.

 

[burnout289]

am i correct that the sending unit is grounded by the tank itself? if so, the ring that hold the unit in place needs to be clean [as well as the tank opening] or it could be causing bad ground. my gauge has never read correctly, and someone else on here a while ago had the same problem but fixed it by replacing that retaining ring.

 

[tach]

ive been thinking about it all day and the ground on the tank was really suspect when put the tank on thanks guys im probably sure its that.

 

[slapper]

am i correct that the sending unit is grounded by the tank itself? if so, the ring that hold the unit in place needs to be clean [as well as the tank opening] or it could be causing bad ground. my gauge has never read correctly, and someone else on here a while ago had the same problem but fixed it by replacing that retaining ring.

Yes.

 

[67GTA-FB429]

When you put inthe new tank, did you get a new pickup and float/sending unit? If so, you need to adjust the float. You will need to drain the tank, remove the pickup, and carefully bend the float arm up or down (I think down in your case). The tank is also ground through everyone of the bolts holding it in.

I replaced my tank last spring and it took me three tries to get it right.