Distance to Empty Help

it doesn't calculate by how many miles you've driven, it calculates by your average mpg's.

you drove 26 miles, but used 39 miles worth of fuel.

 

I have observed that with my Prius, it's estimate of distance to empty is very conservative.

If it says I have 80 miles to go, and I drive 70, you would think it should then say 10 miles to go. But it will in fact say 30. I think that it's calculation assumes that during the next 80 miles that you will start driving in a manner that is wasteful.

 

Here's what I did on my last tank.
I drove until DTE=0 (it beeps at DTW minus 20 and tells you that you're "low" on fuel.)

I made a mental note of the trip odometer.
I drove an additional 80 miles and loaded 11.2 gallons of fuel.

Given the Prius' advertised 11.8 gallon tank, I was probably good for an additional 20-30 miles.

Takeaway: DTE...isn't.

My car has been doing this for 82,000 miles.
I swag my stops to load about 10 gallons of fuel, more or less so that I can keep a mental running tally of my real-world efficiency.
10-gallon fuel loads makes for easy math.

Anything else, especially with the "see-no-evil" multi-misfunction display and you're not looking at data, you're measuring noise.

Good Luck!!
Enjoy the new car.

 

Just ignore all the car's predictions, bells-and-whistles. Drive a few tankfuls, doing what you can to maximize mpg. Fill up the same method each time. Personally, I fill 'till it clicks off, done. Also, I don't go chasing distance per tank, just fill when it's geting lowish.

Record the odometer at each fillup, and the gas quantities. Armed with that data, do the mpg calculation. Watch it for several tanks, see how it goes, what works.

 

You are expecting far far too much from this display. It is just a forecast of distance remaining, based on past MPG history. But past performance is not a guarantee of future results, especially when you just acquired the car and have almost no accumulated MPG history stored in the computers.

Even after you do accumulate a significant history, this display will still show substantial inconsistencies, because fuel consumption is still highly variable from factors the computers cannot forecast -- weather, speed, road conditions, type of traffic, short vs. long trips, hot vs cold starts, driver (in multi-driver households), load, hills and mountains and other elevation changes, different fuel blends, etc.

On top of that, the calculation excludes roughly the bottom two gallons as a safety margin. You can run significantly beyond DTE=0, but the car has given you its final low fuel warning. When or if you actually run out of gas, you can't legitimately claim that you had no warning. The safety margin is large because the unforecast variables are so large. And because, when the first warning is delivered, you could be a very long distance from the next gas station (see pictures below).

For some idea about the car's typical bottom-of-tank behavior, read just the first post of this thread:
[WARNING] Running out of gas (Gen III) | PriusChat

 

EVERYTHING the car and the manual tells you about fuel level is very conservative. Toyota doesn't want you running out, and doesn't mind if we're so cautious that a whole third of the true tank capacity is never used.

I find that the total of DTE shown on the display, plus the distance driven since the last fill-up, is remarkably consistent, usually around 640 miles (except when the gauge is showing full).

 

My "Miles to Empty" reading zero's out with 2 gallons left in the tank.
2 gallons is a lot of gas in my car.

 

I wouldn't recommend this, but I had my indicator saying "0" and drove for a solid 40 miles through the red rock on the 15 fwy in Arizona. To be honest, I was sweating a little. Now, I just refuel when the last bar blinks.

 

You don't really need to sweat in typical Gen3s (Gen2s with bladders are a much different matter) if the next fuel that close. Read the first post of this thread: [WARNING] Running out of gas (Gen III) | PriusChat

But if fuel is a long way away, such as in these places, safety would suggest turning around and backtracking to the nearest open station:

 

What if next gas was 50 miles away and you had 2 bars left that drained to none in less than 20?

 

I just filled up at 602 miles and 80 miles past Zero on the "Miles to Empty" indicator.
55.21 mpg

 

well done! stretch it to 100 next tank!

 

How many miles was that past the last bar starting to flicker? Toyota says 1.6 gallons are left at that point, and that's probably conservative. The one time I reached the flashing bar, miles-to-empty said 24. Coincidentally, that was was less than one block before entering a previously planned fuel stop.

 

Upon flash, our Prius has 2.15 gallons remaining. Reset B tripmeter and when miles/MPG ~= 2 gallons, refuel NOW!

Bob Wilson

 

The flashing pip & the beep are the early warnings. Keep driving past 0 MTE and the yellow triangle will flash and a message will pop up on the MID.

 

That yellow triangle and MID message must be specific to certain trims. They were absent from my 2010-II, and are absent from my 2012-Three. For both cars, the beep and flashing pip are the very last warnings.

 

David. FYI, I kept track of all information at each fill up for the first 50,000 miles. Some times the tank said 0 miles remaining some times it said 250, all varying based upon how much was left in the tank. However, over the 50,000 mile period, using manual calculations, ON AVERAGE, there were 1.8 gallons more left in the tank than the car indicated, based upon the mileage shown on the dash. Over that same period I averaged 50.2 mpg. Being conservative, when the beeper went off and when the "remaining" miles said 0, I didn't start looking to fill up for the next 60 to 75 miles. Some techs say it's a cushion, others say it's a selling feature. Also, the mpg on the dash vs. manual calculation varied from next to no difference to 8 or 9 at times. Just keep track for a while of how much gas was left in the tank at each fill up vs. what the dash indicated until you get comfortable with how many more miles you can REALLY drive.

 

I meant 52.0, not 50.2.

 

Nothing wrong.

• The 505 miles was a guesstimate based on your prior tank
• The 466 is a guesstimate based on the driving thus far on the current tank. Perhaps the drive to work is a bit uphill, or was windy or wet ?