Fuel gauge accuracy

[1979C20]

I noticed something strange about my fuel gauge, its almost lije the sending unit is for a 10 gallon tank, because when my truck is almost empty, and I put 12 gallons in it it phts the gauge at full. And when I fill the tank, it goes a little past full and stays there for quite a while, then starts coming down. So how do i make my gauge more accurate?

[PromiseKeeper]

Been wondering the same about mine. When I fill it, it never quite gets to 3/4. I run it down below 1/4 and it takes less than 10 gallons to fill it.

[Captkaos]

They aren't 100% accurate due to the arched path, but it should show E-F.  I would question the sening unit.

[1979C20]

Empty is correct, ran out a few times. But 12 gallons shows full on my 20 gallon tank

[bigchevyc30]

i tihnk mines the same cause when it gets below 3/8th of a tank the gas guage moves alot when braking accelerating and it moves down alot on start up from where it was when a parked it so really i dont know how much is really in my tank

[bake74]

     The sending units on these trucks are not perfect, I have noticed that sometimes they do not swing the whole arc.  In my 74 it does the same thing, empty is empty, but full stays full for awhile, I have taken it apart a couple of times, but from what I can tell the float only goes so far up and then stops.  It is like the arc of the float is not long enough.
    I would much rather it show empty when it is empty, then show full and end up running out of gas before it show empty. 

[1979C20]

Is therr any way to modify the sending unit so full is actually all 20 gallons? Maybe shorten the float arm? Or bend it so its at the top of the tank when its at the top of the arch? Or maybe make the arm longer and point it towards the back of the tank so that it reads more accurately?

[Captkaos]

If yours isn't showing FULL when full you have a sending unit problem.  Mine work fine on the extremes.  The accuracy is off on the area between...

[1979C20]

When I fill it, it shows just past full for a really long time.

[roadrage41]

as all of my stuff is new except the gauge i can tell you getting a new one doesn't make any difference as far as that issue goes. my boss' new thousand dollar aeromotive setup is super accurate, i'll just keep putting gas in my tank when it's below a half and save the 900 bucks, lol.

[Captkaos]

When I fill it, it shows just past full for a really long time.

This is pretty much the norm...