Differences in sending units?

[JCribb]

I replaced my sending unit in my 94 Z71 a couple years ago, and since then I noticed that according to my gauge reading on empty, my refill gallons are between 5-8 gallons shy of where it should be.

Being that I have a shortbed I have a 26 gallon tank, and I should be buying 20 to 24 gallons per fill up. I have been purchasing 15 to 18 gallons, and I’m not complaining about buying less gallons, but I don’t want to run my pump dry thinking I have plenty to use if it’s not in the tank deep enough.

So now that my rambling is over, are there differences in sending unit depths for whatever reason or another? My build date is 06/94 if that means anything. The parts stores show codes for a series of Vxx codes, but I’m not finding them on my RPO code list.

I’m only curious about this because my 97 Z71 from 10 years ago had a refill capacity of low 20’s with the same size tank.

 

[Schurkey]

First Guess: You have more fuel in the tank than the gauge is indicating. You buy 15--18 gallons because there's still eight-to-ten gallons left, unused.


Alternatively, the tank could have a really big dent in it, or the sending unit float arm is bent.

 

[JCribb]

First Guess: You have more fuel in the tank than the gauge is indicating. You buy 15--18 gallons because there's still ten gallons left, unused.


Alternatively, the tank could have a big dent in it.

No tank damage, so I’m still at square one. Which was bringing me to my wonder if there was a difference. I have a late 94 build, so I wasn’t sure if I had 95 parts or if there was ever a difference at all.

 

[JackE]

You're not going to kill the pump by running it dry once. I would carry a 5 gal can and run it down to empty to see what the heck is going on. That will let you know if your pump is sitting deep enough in the tank. It's very possible the float arm is bent a little, or the new gauge just reads different in the tank from the old one.