I thought I was crazy! I cleaned the ground last year and it started working. Now since June it would occasionally go from full to 3/4 letting me think its was functioning.
I'm spitballing.... I wonder how difficult it would be to refurbish an OEM unit? As Cook mentioned earlier in this thread: there were people who rebuilt them at one time but who knows if that's even a thing any more. It seems the most difficult part would be sourcing/installing a new sock, as testing the unit appears to be the lesser of two evils and is depicted very well early in this thread. Looks like a good winter project for me with my original sending unit.
These guys specialize in Harley Davidson fuel senders, but they do automotive senders as well. https://tristarrradiator.com/
Isn't an old hack removing the sock so it doesn't get clogged up? I know the RobbMc sender is devoid of one.
A couple of spitball questions here: Has anyone experimented with a float-less sender like the ones Thanks Inc. sells? How about the new Holly laser one? I'm wondering if the laser is more of a gimmick or would it actually be more reliable? Since I'm on the subject I'll share an interesting failure mode of my sender in my 70 Skylark. I had just replaced the in-tank sender with a brand new one and it was working great with my new gauges. I then decided to take the car to it's first ever drift day, and noticed afterwards that my fuel gauge was dead again! I was wondering how the heck the sender had broken so fast or if my wiring job was terrible, granted I was put in a car through higher Gs than normal. Turns out that the fuel baffle in my original 1970 tank had become loose and was banging around in the tank and had literally knocked my sender to pieces! This is what I pulled out of the tank:
