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Launched in 2009 FuelGauges provides an online community for truck drivers to track and manage their fuel mileage.

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Why is filling tank necessary

Why is a full tank necessary to accurately determine fuel mileage? If you have the amount of fuel you put in, and the miles you drove, why can't you just figure fuel mileage on that? I mean, my truck has a computer system that figures my fuel mileage just fine

The reason I ask is because I cannot ever fill my tank. I run very heavy loads that are at most 400 miles 1 way.

I want to use fuel gauges for the averages.

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First of all, thanks for the great replies. Secondly, I now have a new question.

How do you shut off 1 tank?

I could definitely run on 1 tank, but filling up to the same place is near impossible because my fuel gauge is off.. I don't do any runs over 700 miles total and there are many times that I have less than 1,000 pds of play before i fuel. So filling up both tanks even once could cost me my dedicated run.

Thanks again for the info so far

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depends on what truck you have. you may have a shut off valve already installed or you can have a shop put one in for you.


On my Freightliner, above the drivrs side tank there is a handle and instructions on which way to turn for shutting off either tank.


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fuel mileage is calculated on the miles driven divided by the fuel used. without going from full tank to full tank you don't know what you've used. say on a 400 mile run you put in 60 gallons that gives you 6.66mpg but you might've used 65 gallons and it brings the mpg down to 6.15. the shorter the distance between fuel ups the bigger the difference made by even 1 gallon of fuel.

you can shut off one tank and run on a single one to save on weight and may be able to top off to calculate your mpg correctly.

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Try to top off once and record your milage.

Then keep track of all gallons added even if you don't fill until you have the opportunity to top off the next time( even if that is a month or more) record milage and figure MPG.

Your ECM may be correct ..... probably not

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You don't have to top off to calculate fuel mileage, you just have to fill the tank to the same level between calculations. The easiest way to do that is to top off. Maybe you can come up with a way to get tank to same level each time, kind of like a false top off.

If I were doing your run, I would shut off one tank and just fill the other tank.

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you also prevent condensation in your tank so better fill up to the top especially if your truck gonna sit for a couple days

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Amanda Smith will be eternally grateful.
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