Fuel Guage

[blzrgb]

My 84 k5 is giving some trouble with the gas gauge. New tank,
straps, sender and gauge from LMC. Worked perfect
all summer but now shows way over full all the time.
I think I'm right on this, but doesn't an "over" full gauge
reading mean that the sender wire back to the tank is
broke or not connected ? Provided that all else is in good
working order that is.

 

[skunked]

more often it's the ground at the tank sending unit.

 

[dyeager535]

Not even taking the time to think about this fully, with truck in "run" (not started though) crawl under truck, disconnect sending unit wire. Does gauge change position? Now take a short piece of wire, and ground the "upstream" side of the connector. Does gauge go opposite way? Needs to peg out both directions.

If gauge responds properly to both tests, problem is "downstream" of the connector. If guage does not respond properly, from your description, wouldn't be surprised if the gauge cluster connector is the issue, or the clips that make contact on the back of the gauge.

I agree though, inspect the ground at the tank while you are under there. Very common issue, never hurts to check grounds. I ALWAYS coat electrical connections of any type with dielectric grease when I have them apart, in an attempt to keep corrosion problems at bay as long as possible.

 

[blzrgb]

Ok I'll give the ground a look.
I used a bunch of dielectric when I was replacing everything.
The gauge was a tight fit into the clips, but maybe some rough
trails shook it loose but didn't seem likely.
Thanks !!!