Fuel Gauge

Well I did some looking into this before I am posting this question but I cant figure it out. The full ohm is 10 and empty is 73...Maybe I have the tester set to the wrong setting, I can never figure those damn things out anyways. Well when I put the positive lead of the volt tester to the lead off the sending unit and then the negative to the steel fuel line (which I cleaned all the gunk off and it was shinning) the volt meter read .89 ohms... So I may not have the knob set to the correct spot on the tester. But this is what is happening, the gas gauge does not work. I did the test and took the lead wire and grounded it out (not to long because I heard that could damage the gauge) and the needle went to full, unhooked it and straight back down. So I was reading around and read that there is suppose to be a ground strap off the sending unit bypassing the rubber line and then clipped onto the steel line on the chassis, my car is missing that. So I took a jumper wire cleaned off both the line and the sending unit hooked it up and tired to see if it worked. The needle barelyyyy moved, I mean hardly any. So I dont know if the tank is empty...it may be, or if the sending unit has gone to the way side. I kinda want to pull it out and check it but looking at some of the pictures of sending units that have come out of these cars I dont want to take it out and it be...well something wrong with it where I cant put it back in, I dont have any cash right now to buy a new one. So whats the best way to check and see if the unit is bad or good without taking it out...I probably need to be schooled on how to use a damn volt gauge...

Thanks,
Ryan