76 Gas Gauge problems

[76chevyc20454]

I have a 76 C20 454, th400 single tank. when i bought the truck the guy said the gas gauge worked. well while driving home about 20 miles it was on E the whole time so I thought he lied or im about to run out of gas. Anyway i stoped at a gas station and filled it up it held 20 gallons and i started the truck and it went to full. the problem im having is if i hit a bump when i dont have a full tank my gauge needle goes everywhere. i didnt no if this could be electrical or if its just the float moving up and down. It just bothers me lol. What do you guys think?

 

[firebane]

Time to check grounds at the tank.

 

[76chevyc20454]

Time to check grounds at the tank.

Well i noticed there is a wire coming from it looks like around the gas gauge that's not hook up to anything. Didn't no if it could be that or not cant find a wiring diagram.

 

[76chevyc20454]

And it had a new gas tank put in recently before i bought it.

 

[firebane]

And it had a new gas tank put in recently before i bought it.

Well there shouldn't be any wires around the gas gauge as it should be fed from the printed circuit board. If this has been bypassed its really hard to say what is going on.

Also a new gas tank is even more reason why you should check grounds and the sending wire.. Its easy to miss these or not install properly.

 

[76chevyc20454]

Well there shouldn't be any wires around the gas gauge as it should be fed from the printed circuit board. If this has been bypassed its really hard to say what is going on.

Also a new gas tank is even more reason why you should check grounds and the sending wire.. Its easy to miss these or not install properly.

im not sure if its to gas gauge just a wire up around there not hooked up, has no power to it. ill check the gas tank though and see if that will help. Thanks man!