Gas guage again

I'm ready to pull what hair I have left out!!! Here is what I checked this morning. #1 I found the manual for my multi meter so I was using it correctly. I checked ohm reading on the fuel guage.

It said 157, I checked the old guage and the reading was 117.
I clamped the sending unit in the vise and tested it, the numbers changed as I moved the float arm, so the sending unit should be good.
The slip on connector on the sending unit wasn't a good fit, so I bent the tangs down a bit so it fits tight on the spade.
I connected the wires to the sending unit outside the tank and moved the float arm, nothing. I took both the power and ground wires off and checked them with a test light hooked to a good power source and ground and both wires are good.

I grounded the wire from the guage and the needle moved to full from empty. When I put the sending unit in the tank, hook up the wires, turn on the key for power and the needle doesn't move
( it has about 3/4 tank of gas). If I tap on the guage, the needle goes to full and stays there.
The sending unit tests good, the wires test good, the guage tests good. Why won't it work???? It's probably something simple that I am missing, but I can't seem to figure out what it is. Any ideas??

When tapping on the gauge made it do something, that says a bad connection at the gauge or a bag gauge.

Try taking the sending unit out and moving it through the motions again now that the gauge is moving. Could be the sending unit needs to be fine adjusted to get a good reading. You may never get it to read accurately through the full range in the tank, but it should out of the tank. Shoot for a good empty reading.

If it refuses to work, look into marine gauges. Thousands of faces to choose from, waterproof gauges, better quality than the aftermarket.

Best part is the sending unit, it's a simple sliding sealed magnetic pickup. Measure the depth of the tank, buy the longest that will fit without hitting bottom. Easy in and out, no arm to bend or get hung up.

I tried tapping on the guage to get the needle to move to the full mark and then moved the float arm, no movement of the needle. I'm going to get a different guage and try that next. Thanks for all of the help, this has been more than frustrating!!

Does the float actually float? Is it binding on something in the tank?

Yes, the float floats, no, it's not binding up in the tank.

From your test , both the fuel level gauge and sender do work , but not in conjunction with each other.
The fuel level gauge and sender must have the same resistance and the same ground potential to function correctly. Fuel level is one gauge/sender combination where mixing brands will generally work. Just be sure the correct electrical match is used.
Now don't ask me how to check the resistance of the fuel level gauge and sender as it's far above my pay grade ( as we used to say at work ). I'll leave that for the electrical gurus.
Dad never trusted the fuel gauge , he always stuck a yard stick in the tank to figure if he had enough fuel to accomplish the task at hand and at times he would run out of fuel , if it were to occur, it always was when he was at the farthermost location from the fuel supply . LOL