I need some fuel sending unit experts please

You still have the old fuel sender? Test it to make sure the resistance changes as you move the float. Then get yourself a couple long pieces of wire. Connect the first wire to the wire at the sending unit location, and the old sending unit. Connect a second wire to the battery ground and the old sending unit as a ground.

If your wires are long enough you can sit in the drivers seat with the key on and move the float on the old sending unit while you watch the gauge.

Oil pressure unit connect a long wire on the end of the wire to the unit, run the wire in the car so you can check for continuity with the wire from the gauge. This will tell you if the wire is good between the gauge and the sending unit.