fuel sending unit and fuel gauge trouble

Hello All,

When i bought this 1970 dodge dart, they had removed the factory fuel tank and put a small fuel cell in the back with no fuel sending unit.

I put a larger fuel cell in with a sending unit.

https://www.summitracing.com/parts/jzp-251-012-01

I hooked up the factory sending unit wire to sending unit, and the other lead to ground, and i get nothing on gauge

Any ideas? Does anyone have a wiring diagram?

I have checked all the obvious things.

Thanks