Got the vats issue solved and started looking at my fuel gauge reading slap full issue. Was told this was usually a hung up float. So having had a fuel pump put in a year or so ago, decided to pull tank again. Got tank out sending unit looks ok float was not hung. And with wires unhooked gauge still reads full. So how do i check sending unit? Also how to check gauge? When calling local Gm parts house told the gauge is no longer carried, so where to get one if needed?

 

i have same issue. The gauge reads full because it's getting +12v, the single in is a resistance. I can not figure out WTF either. I think i may have pulled out the signal wire when I put the tank back in. I tried every wich way on the gauge but it eaither read empty or full, no in-between. If you have a digital volt meter that can read ohms, try it on the signal wire.

I've been told by TGO members that the sender is just a potentiometer, and that is what it looks like to me, so it really cant go bad. But who knows. A new sender is HELLA expensive! $350 was my last quote from GM and Advance.

 

I was told right at $500 by gm and I think oreillys could get it for about $250.
What gets me is even with the sending unit disconected it reads full. Maybe someone with experience can help us.
Like what should sending unit read full, and also empty. Tried to read it with a fluke and it was hard to get stable readings. And how can gauge be tested?

 

the gauge reads full when the signal is not present because the signal wire gives the gauge a resistance to properly set the gauge where it should be. With out it, your getting a full +12v to the gauge.

To test the gauge, get a variable resistor and put a +12v to one end and the other to the input on the gauge, change the resistance and watch the gauge go up and down. Get a new cluster on ebay, that is what i did.

 

Thx 88, got a junkyard gauge, stuck it in turned the key bang to the top. Cycled the key and it went to almost empty. Found that very slight movement of the float caused the gauge to peg and more wiggle and jiggle would get it to reset only with float on empty. Figure its the sending unit. Know where a tank with everything is for $70 , just wish I knew how to test.

Oh, read the pins in the dash with fluke and it would see a change from low to full but jumped all over the place. Maybe if I stuck it in a bucket af fuel and moved it slowly might see a slow curve. Gonna go look at the tank tomarrow.

 

Ok, got the sender out of a junker, now all works fine. Had to buy tank and all. So, now have a good tank and extra pump. Free for anyone to pick-up or if you pay shipping.