Heres a question. When I bought my truck in the spring I picked it up with a full tank of gas and the computer said I had 720k till empty and I refueled it countless times since. I on purpose ran it till it had 10k till empty and filled it up and it said only 680k till empty?? I only once had it say 710 k till empty? Theres has been many times I fill it to the brim with gas and it says only 643 till empty??

Is there something wrong with my computer? This drives me nuts! I refuel on level ground.

 

You don't get the same DTE on every fill-up because your running average fuel economy is always changing.

 

Artic Cat: My understanding is that the reason it shows differently each time you refuel is because the computer calculates how many miles (or kilometers in your case) you will get based upon the fuel economy data in its "memory". For instance, if you drove your truck fairly hard for a couple of tankfuls of gas, your average kilometers per gallon (or liter I suppose) would be fairly low. If you filled your tank after this "hard driving" the computer would calculate how many kilometers you should be able to drive by dividing how many liters of fuel were in the tank by the AVERAGE kilometers per liter in its memory. On the other hand, if you drive your truck easy for a couple of tanks, then fill it up, you would be dividing the same amount of fuel by a higher kilometer per gallon rate and hence, your displayed kilometers 'till empty would be HIGHER. All this being said, what I don't know is, how far back this memory of mileage goes back in the computer (i.e. one tank, three tanks, 1000 kilometers, etc.).

One thing I have definitely noted with my truck and the mileage display is that it ALWAYS displays .4 to .6 miles per gallon HIGHER on the display than it does when I calculate it myself. I'm weird this way, but I've entered every tank of gas I've ever put into the truck onto a spreadsheet and without fail, I'm always lower than the readout in the truck. Even so, I am quite happy with the gas mileage as I am averaging 14.58 mpg for the first 26,000 miles. I have the 5.4 liter 4x4.

 

JohnandDar;

You beat me to it and you did it in a much simpler way than my long winded explanation. You also answered my question. Thanks.

 

My vette's computer is about 2mpg over reality as well. That's why I don't pay any attention to the gas mileages that get quoted in this forum. Unless you calculate the actual miles driven divided by the actual total gasoline purchased, and do it over many tankfulls (to reduce the effect of the fill error on that last tank you put in) it's just subject to too much measurement error.

The computer is good for seeing if you are personally doing better or worse over time, but not for nailing the actual consumption (or comparing to others.)

 

When I was hauling *** down I-20 with a 5x8' U-Haul and a bed load of stuff, every time I filled up, the DTE said only about 330-350. It took about a week's worth of normal driving for it to re-adjust to sane speeds and no load where now it registers 400+ miles to empty. I wouldn't worry about it.

 

Just out of curiosity Arctic Cat what size gas tank do you have?
I have a 30 gallon tank according to my window sticker and many fill ups and the most I have ever seen on mine is about 460 miles left till empty. Would love to have a bigger tank like yours.

 

I read somewhere....I think in the OM that the MPG and DTE were based on the average fuel consuption over the last 100miles.

 

Thanks for the replies! I did not know that. And knowing is half the battle. Over the Christmas holidays I'm going to drive it some what easy compared to how I normally drive it. I wanna see if this will work.

GBTexas you asked what size tank I have I believe it's the 120 litre tank. I think that might be 26 or 28 gallons.

So if I disconnect the battery for a moment this will reset my computer and bring it back to factory setting? I think I will try it this weekend.