69 chevy fuel gauge problem with a fuel cell

[painteralg]

Hello all, I have a fuel cell that has a Chevy 0-90 ohms sending unit but my gas gauge reads 1/8 with the tank full or empty the sending unit is currently reading ~48.5 ohms with a half a tank right now. And the float is not leaking. Below is a list of things I’ve checked. Any ideas would be greatly appreciated.
1, With the ignition "on" and the sending unit power lead disconnected the gauge reads past full.
2. With the ignition "on" and the sending unit power lead grounded it reads empty.
3, I removed the sending unit from the fuel cell and with the float at the bottom it reads 2.2 ohms and with it at the top it reads 89.8 ohms.

I’m reading ~8 VDC at the sending unit power lead as well at the fuel gauge terminal at the fuse box. Also does any one know what the G and the S stand for on the sending unit terminals?

Please help!!!! With any ideas. Thank you

[sweet70beast]

You never said if you have the fuel cell sending unit grounded. With the guage going past full then to empty I'd say the wiring and guage are working, and the sending unit seems to be working with the ohms you state. Is the fuel cell made of plastic? If so it isn't a very good ground path, I'd hook a wire somewhere on the sending unit and ground it and see what happens.
My guess is the the G is ground and the S is signal (hot).

[painteralg]

Thank you for the reply,
Sorry I forgot the mention the ground, I do have a ground wire from the sending unit to the frame but yes the cell is plastic.