what size gas tank ?

[spearchucker]

The rheostat (I think thats the right term) that the float arm uses to "send" the fuel level to the gauge gets dead spots on it. Some sort of black corrosion from what I saw.

As mentioned, 0-90 ohms should be the sweep from either end of the gauge, but the problem is you can't see if there are dead spots without moving the float arm. It only takes a tiny amount of fuel slosh for the float arm to move, which influences the gauge.

Good point. Sorry, but I work off of theory alone, real world situations aren't a factor in my book.
If the slide on the rheostat is tarnished though I'd still try cleaning it first before dropping a couple bills for a new one.

 

[blazerguy 90]

Thanks for all the information, I will have to wait until this weekend to get into this deeper, but here is were im at now, with the key off and the sending unit unplugged back by the tank the gas gauge is still reading way past full, I was thinking that with the sending unit unplugged and the key off the gauge should have gone to empty, but no, still reading past full, what I did notice though is that when I unplugged the sending unit and turned the key on the gas gauge actually went past full more than it was before. any idea why it would do that ?.
sorry for all the questions, im by no means a pro when it comes to tracing electrical problems.

 

[gravdigr]

Check the ground from the tank to the frame. Also check the wire from the sending unti to the guage and make sure it isn't grounding out.

As for size of the tank. If there's like 1/2" between the skidplate and tank it's a 31 gal, if you can stick your hand in there is is the smaller tank. I'm 99% sure they used the same skidplate for both tanks.

 

[blazerguy 90]

The first thing I checked was the ground from the tank to the frame, no change, so it looks like I need to trace the wire from the sending unit to the gauge.