1. I don't know what trying cork or rubber gasket has to do with anything but we were asking if you have tested the float on the sender in a container of water to see if it stays afloat for awhile. You now say you tested it.
2. I asked if gauge was mounted in dash on all tests. Never moved from there and wires not changed.
3. I said be sure the ring tongue terminal on the green wire is against the sender metal, not a washer. Like when you held it against the sender by hand.
I will repeat ......
I am focusing on this being a clue. Like good ground when sender is out and bad ground when sender is in. So need to know how you are grounding the green wire when sender is out verses installed on tank and putting terminal under screw head and tightening the screw down on tank sheet metal. Be sure ground terminal is touching tank flange directly and not on top of a washer. The washer could be rusty or corroded or not conducting.
4. Don't know what
You have shown the sender to be working when out of tank. So it's not faulty. We are looking for something different between testing out of tank and in tank.
So far these things
1. Float??????????????
2. Ring tongue touching directly to sender when sender mounted in tank.??????????????
3. Wiring left in place except the green wire. When testing, was ALL wiring, except the green wire on the sender kept in place. not moved or disturbed??????????
4. Gauge or it's wiring not disturbed.??????????????
5. Float or arm not binding inside tank.????????????
We understand all is new. We understand your wiring. We, including you, are trying to see what changes between hand test and installed test. THIS IS THE KEY. Focus on that with us.
