Fuel guage/sending unit issue

[fallguy]

Ok this ones a real pain. One day randomly my driver side tank ('86 k10 dual tanks) jumped to waaay over full on the dash gauge. It still functioned just didn't know how full I was and as it emptied the needle would go to half tank. So I'm thinking sending unit. Which I replace...badly as those 3 little fuel lines are a real SOB to hook back up while under the thing. But I've just found a site that told me to screw the little 5" lines and replace with 2' long lines and just let them coil up...MUCH easier I'm thinking! Anyway I have to do that cause I'm 99% sure I didn't get the lines hooked up right cause it's sucking air and eventually the engine starts sputtering and conks out. But regardless the tank still reads over full! I've got a good ground and the guage works perfectly when I switch to the passenger tank so someone please help!

 

[lusktommy]

you might try replacing the switch on my 1984 it did the same thing and it was the switch not sending enough voltage because gauges read off of resistance and not having poor connection will cause them to do exactly whats happening. and a sending unit could i suppose but i would try buying a little switch they are easy to change and alot cheaper and less headache