Fuel sender?

[kcrsq]

Installed new universal sender. Then gauge didn't work. Ordered new gauge and now gauge wont read full. My old sender had a wire coming from ground connector landed on a screw in the base. The new sender has no screw to put in under so I left it off. It was a wire from a ground wire to the base...
New sender is suppossed to be 30-240. Ohms. When I check it it read 34-255. If I put a screw driver between the bottom of the base and the little plate that holds the senser. It will read full on gauge( with the float up). basically make the base contact the metal plate that holds the sender.
Is the new sender bad? Do I need that wire? I tried holding the wire to the ground wire and the base and nothing happened. The old original sender seems to be made from a different metal than this one...

 

[glenn property of pam]

Re: Fuel sender?

universal sender sounds like a automotive sender that was designed for a metal tank thus it didnt need a ground as it used the tank. in a plastic tank the sender will need to be grounded. the diffrent metal is due to additives in the gas that eat some old type sensors (has been know to eat the new ones as well). the sender wire from the gauge when grounded should read full. the ohm reading is with in 10% which is nothing to worry about

 

[kcrsq]

Re: Fuel sender?

It has that spade terminal ground but the old one had a wire t-ed off the spade ground to a small screw on the base of the sender. Not under a mounting screw but another smaller one. The new sender doesn't have that small screw option. Also if I touched a wire coming from the spade terminal (with the ground on it) to the base-no change

 

[Silvertip]

Re: Fuel sender?

Once again, here is the diagram for the fuel sender circuit. If the gauge is reading half full but the tank is full, the float is hung up on the side of the tank or the arm is not adjusted properly, or the depth of the sender is not right for the depth of the tank. Yes, the metal shell of the sender MUST be grounded. That means to the engine block or the negative terminal of the battery or to a ground buss. In other words, ground it wherever you find ground. The resistance readings you have are correct for the sender. Remember that when adjusting the float arm, you want an accurate reading for EMPTY, not full since you know when it is full. You generally cannot get a perfect reading for empty, 1/2 and full. It is one or the other.