[RockBit]

Bill:

Here are photos of the top of the tank and fuel sender from ERA812. I suspect the sender in your car is the same. There is no ground wire on the sender, the ground is established through the mounting screws to the tank. This is where the ground on my sender failed due to the sealant on the screw threads.

Since you are getting an open circuit between the white wire and ground, this indicates your sender is not grounded properly.