1996 c1500 fuel guage

griepp06 · July 6, 2020

So I just bought a 1996 5.7 fuel injection c1500 that needs some work as the check engine light is on but that I will take care of thats my next project. My main concern is that when the tank is empty it says 1/2 full on the guage and when full it says way past fullon the gauge. Please advise weather to pull the bed off and replace something inside the tank or if its the gauge or something else completely.

riverbanks · July 6, 2020

Yep, sending unit in tank faulty

thx1138v2 · July 6, 2020

Here's something to be aware of if that truck had 2 different size gas tanks: I put a new pump/sending unit in my '94 and the auto parts guy asked me if I wanted the HV model or the non-HV model. I asked him what the difference was and he didn't know. So I got the "HV" model and it doesn't read correctly. It's not as bad as what you described but it's still annoying. I later found out that truck had 2 possible fuel tanks and the HV designated the (H)igh (V)olume tank - the larger of the two.

griepp06 · July 13, 2020

okay so i think i have the smaller of the two options but am unsure. im going to take the bed off so i can see the top of the tank and get access to the sending unit and replace it and makse sure that i get the reight one depending on the size tank. what were the two sizes in gallons?

thx1138v2 · July 14, 2020

Shortbed trucks were equipped with 25 gallon tanks; longbed trucks were equipped with either a 25 gallon or 34 gallon tank. Mine was a 25 gallon tank because I have a short bed. The better way to tell is how much it holds when the gauge is near empty.

griepp06 · July 14, 2020

Well I have a short bed so I guess that means I have the smaller tank and a non HV

thx1138v2 · July 14, 2020

Now the question is which version of the sending unit do you have? It would make sense that it is the HV sending unit. It may have been replaced before you got the truck so the only way to tell is to pull the bed off and then remove the pump/sending unit.

LDM · July 14, 2020

Don't just assume it is the sending unit in the tank. The gauges on these trucks often stop working or get outside of spec. My brother has a 97 K1500 and we had to replace the tank and fuel pump due to failure, which still didn't fix the issue withe gas gauge randomly jumping all over the place. Turned out to be a bad air core motor in the gauge, which was fixed after I swapped out the entire cluster due to the RPM motor and speedo failing. You used to be able to get the motors on ebay for a decent price and fix the cluster but the last time I looked they were pretty expensive. You may want to see if you can find a replacement cluster in a junk yard first, they are much easier to replace than the fuel tank/pump.