I installed the RT-E regulator and bench tested with a cheap Chinese sender (see my post #13 with a picture). As I moved the sender float, the gauge would move up and down. The back of the fuel gauge has thin dense cardboard to prevent it grounding. It was fit snugly between the posts.
I have the cluster loosened and ready to come out again. I might try what Bob said in post#20, to use a separate wire outside of the car from the sender straight to the gauge to see what happens. I’ll double check to make sure the cardboard is in place behind the fuel gauge, too.
