Is your fuel gauge accurate?

[Suregrip391]

Hi guys, came here to discuss my fuel level “possible issue”, I just bought a 25 2500HD, 6.6 gasser, and wanted to see how accurate the gauge was. Knowing I have a 36 gallon tank, that is 9 gallons per 1/4 tank. I had just over 3/4 tank of gas so I went to fill up thinking I will only need 8-8.5 gallons to do so. It took just over 11 gallons. Is that normal? Will it get more accurate the lower the tank gets maybe? To me, 3 gallons is a lot to be off, no? What are your experiences? 

[newdude]

1 hour ago, Suregrip391 said:

Hi guys, came here to discuss my fuel level “possible issue”, I just bought a 25 2500HD, 6.6 gasser, and wanted to see how accurate the gauge was. Knowing I have a 36 gallon tank, that is 9 gallons per 1/4 tank. I had just over 3/4 tank of gas so I went to fill up thinking I will only need 8-8.5 gallons to do so. It took just over 11 gallons. Is that normal? Will it get more accurate the lower the tank gets maybe? To me, 3 gallons is a lot to be off, no? What are your experiences? 

 

 

The gauge has some buffering to it, especially if you have an LT or higher with the new digital dash.  I'd say that yes, once it reaches somewhere around 3/4-1/2 a tank that the gauge gets more in line with fuel remaining.  

 

In my 1500 LT with the new dash, you could drive 50-75mi and the gauge barely even moves from the F mark.  When the light comes on and says either 40mi or turns to LOW, when I fill it there is about 1.5-2 gallons remaining at that marker.  

 

 

Edited December 28, 2024 by newdude

[marpel]

Previously, '12 Sierra 1500 6.2L gas, currently, '22 Sierra 2500HD 6.6L gas. Drive a few times per year to/from Van BC, Can/Denver Co, USA so a lot of gas stops en-route. Every time I fill/filled both trucks when near 1/2 tank, the amount added is always more than the gauge would suggest (and I never go beyond when it auto click-stops). I actually pondered whether the tank was not symmetrical between upper half and lower half (or some components - pump etc sat on the bottom, taking up space) and the gauge was measuring the 1/2 way point vertically (ie if tank is 20 inches tall, the gauge measured 1/2 full at 10), rather than volume. But that would be silly.....

[Suregrip391]

I’ll keep an eye on it, thanks guys. 

[Crazy Canuck]

When mine says it's empty, I can usually get 130+ liters in her, that's where I want it to be as accurate as is can be.  In the middle, I think it is overly optimistic.  It stays 'full' for a long time - i think this it to give people a warm fuzzy feeling longer.

[davidm767]

The Banks iDash does a great job giving you a percentage of actual fuel. The GM gauge can be off as much as 15% percent from indicated from the actual level. Since you have a gasser it may not be AS beneficial to run the iDash as much as the Duramax is, but it gives you a better information than stock gauges.

[lineman1234]

On my 2024 3500 gasser, the fuel gauged is about as close to what it sais as measuring. I would have to go did the note out in it, but. Im not worried about 3/4, i filled around 1/2, and 1/4 then when the light came on for better get fuel, to get a reference for travels. I really wanted a reference for when towing the camper so i didnt get to low depending on what i was getting for fuel mileage that day. No wind, head wind, tail wind, all play when towing the 5ver, tank to tank. 

[Flatus]

If I am at 3/4 tank, mine also takes about 11 gallons to fill up. I have found that the app is actually pretty accurate. I usually use it to predict how many gallons it will take to fill up.

[Pryme]

My scangauge 3 also displays the exact percentage of gasoline still in the tank. 

[Chopper_Man]

Fill up's go past full on the gauge. Cannot simply use 1/4's due to that overage.