Distance to empty

Graham Piccinini

Distance to empty is a simple estimate based on previous fuel economy and driving habits. Losing 2PSI in the tires will screw that estimate easily. Check your tire pressure. If you're truly worried about it - calculate your actual fuel economy (Miles driven per tank divided by amount of fuel that it took to get to full tank again) and compare your actual fuel economy to what other Santa Fe owners get with same engine and drivetrain on "Fuelly.com" If your true MPG is same as others, then you're stressing over nothing.

"Based on data from 79 vehicles, 6,479 fuel-ups and 1,766,898 miles of driving, the 2015 Hyundai Santa Fe gets a combined Avg MPG of 20.43 with a 0.09 MPG margin of error."

Hall

Losing 2PSI in the tires will screw that estimate easily.
Different tires can affect fuel economy too, some help, some hurt.

Kuato

It's calculating based on your average mpg. You're obviously doing a lot of in-town driving, or are driving with a heavier foot than the previous owner.

Bet if you reset the mpg calculstor and take a road trip it will go back up.

Gimpy1

You are telling us that you drive this vehicle to where the gas gauge hits E, you realize if your fuel pump is in the gas tank that you should not go below one fourth a tank of gas.
Yea most fuel pumps are cooled by the fuel cooling it the less fuel the hotter the pump gets.

Nukeman7

Maybe your gas gauge drifted over time. Have you measured gas mileage?
I think Kestas is on the right track here with the gas tank level sending unit malfunctioning and getting out of calibration. It typically works off a polymer float on a pivoting wire arm that controls a contact that moves across a resistance coil. A false reading can occur if: (a) the float becomes saturated/compromised, or (b) the coil short circuits due to wear or deposits. Either condition will cause the resistance to be lower, thereby sending a false signal to the ECU indicating a lower gas tank level than actually exists. This can easily emulate the ~20% difference in the miles-to-empty reading discrepancy observed by the OP. I don't think the true mpg would actually drop by 20% unless the vehicle exhibited significantly degraded performance.

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zray1

On my Elantra the miles to empty are displayed digitally on the dash when I fill up.

Also displayed likewise on my 2002 Jaguar XKR. According to the owners manual and online forum, the miles-to-empty number will fluctuate depending on past gas tank(s) mpg. As my driving locales vary widely from tank to tank I don’t put much credence in the miles-to-empty display. Unless I’m driving cross country. Then it’s somewhat useful to map out my next fill up.

Z

1uz_4me

My GS is very "thoughtful" after a fill up suggesting it can go 500mi+ if ice just pulled off the freeway. Within a few miles it'll plummet back to ~300mi. If the tank has been mostly city driving, it'll poorly guess it can go ~375mi. I don't pay attention to it besides for a chuckle. I fill up the tank around an indicated 1/2 tank left. This is usually about 10 gallons so it's closer to 35-40% left, but good enough for me.

Kestas

Staff member
With nearly every car I've owned, I get more miles from the first half tank than I do with the last half tank.

The gas gauge is not a finely calibrated device. It just tells you when to worry about fillup.

measureman

With nearly every car I've owned, I get more miles from the first half tank than I do with the last half tank.

The gas gauge is not a finely calibrated device. It just tells you when to worry about fillup.
Thats done on purpose.
Years ago Cadillac owners were complaining that the first 1/2 tanks went too quick so G.M. just set the 1st half to move more slowly then the second half.

bobdoo

Gas gauges on cars work the way they do, because most drivers are stupid. The 'curve', full, and empty indicators are where they are to avoid people running out of gas.

Gauges could *easily* be within 5% or so of perfect accuracy, if buyers/users could be trusted to use them properly.

"Contents are hot!" is a needed reminder to too many people.

Driz

Thats done on purpose.
Years ago Cadillac owners were complaining that the first 1/2 tanks went too quick so G.M. just set the 1st half to move more slowly then the second half
I remember that article well. They said the 1980 caddy digital fuel gauge was by far the biggest single complaint in their entire history. It was so accurate they had to degrade it intentionally enough to quell the rage. It was mainly caused by the unequal drop at the beginning mainly due to the filler neck🥴. So much for the upper crust and their brilliance.

CR94

Don't take DTE numbers seriously! It's just a rough conservative estimate by a mysterious algorithm, using assumptions that may not be true. If you know from experience how to interpret your fuel gauge, and know the mileage you're likely to get in the near future, you can make a much more accurate estimate yourself.

PF52

Don't take DTE numbers seriously! It's just a rough conservative estimate by a mysterious algorithm, using assumptions that may not be true.
+2
And it might be calculated from the car's "average MPG" which is probably in fact just a running average from the past few hundred miles, or maybe even less. I usually go for years at a time without ever re-setting my average MPG, but after a few weeks commuting in heavy traffic I can take a long highway road trip on the weekend and watch my "average" MPG climb by 6-8 miles by the time I get to where I am going. I could probably stop and re-fill the tank and I'd be amazed by the sudden crazy long distance to empty!

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