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Fuel mileage and gallons used highly inaccurate

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Fuel mileage and gallons used highly inaccurate

 
  #1  
Old 06-25-2015, 09:00 PM
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Fuel mileage and gallons used highly inaccurate

Wondering if others are seeing this problem on their 2015s. I have a Lariat 5.0 with 36 gallon fuel tank. The gallons used is typically running 10%+ UNDER what it really has used when I fill up, and the average MPG is anywhere from 2 to 2.5MPG higher than what it really gets hand calculated after a fill up. The only fuel measure that seems somewhat close to accurate is the miles to empty.

Today when I filled it up it held 34 gallons, in spite of the gallons used being only at 30.1.

I like all the information it provides, I just wish it were a bit closer to reality.
 
  #2  
Old 06-25-2015, 10:04 PM
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Very Strange. On my 2013 it is very accurate.. Like dead on to .2 off on gallons used, mpg etc.
 
  #3  
Old 06-25-2015, 11:08 PM
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My 2013 is also right on.
 
  #4  
Old 06-26-2015, 01:49 AM
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Mine is just the opposite. A 2014 SCrew. The computer mileage shows about 2+ mpg short of figuring it by hand. Typical Ford truck gauge, the top half is much larger than the bottom half. Right now I have the gauge showing half a tank with a little over 300 miles on the tank. I have the standard tank. I never let my tank get below 1/4.
 
  #5  
Old 06-26-2015, 02:01 AM
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The algorithms and sensing capability in these trucks is somewhat limited, I think. My 2014 seems to be understating the fuel used by about 0.3-0.4 gals in 18-20 gals used and, the displayed mileage is correspondingly higher than what my "hand" calculations show at each fillup. Still, it's more accurate than the lie-o-meter that was in my 2005 truck.

- Jack
 
  #6  
Old 06-26-2015, 02:33 AM
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If our trucks are using the bobbers I've seen in countless track cars, they'll suffer from the same estimation/guessing problems that fuel gauges have had for years. It's getting easier to detect the inconsistencies because of the digital readouts. Much harder to see the variance on an analog needle.

Don't forget the impact on liquid volume/density ambient temperature and altitude can have as well. 4 gallons different? Maybe not, but you'll need a larger data set to compare.

What I find interesting is that my MPG estimation is going up by .1 every few days I drive it (less than 2k miles on it so far). Even by hand I can't make it do that unless the numerator is actually improving .
 
  #7  
Old 06-26-2015, 09:00 AM
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I'll check this out once my truck arrives. I ordered it with a 36 gallon tank.
 
  #8  
Old 06-26-2015, 11:35 AM
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How many miles on the truck? The algorithm will get more accurate over time. It is based on a lot of variables and as time progresses it has more data points to work with.
 
  #9  
Old 06-26-2015, 02:24 PM
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My wife's 2010 Escape reads about +1 mpg over hand calculated
Mt 2014 F150 STX (simple cluster) reads about + .5 mpg over hand calculated
 
  #10  
Old 06-26-2015, 04:58 PM
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Location: Western MA
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just filled mine .8 gallon off. usually click the gas nozzle a couple of times , but did not this time. Close enough for me. Mpg was reading 19.8 . It is a truck so these figures are meaningless to me.
 
  #11  
Old 06-26-2015, 09:36 PM
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Filled mine this AM. Took 14.7 gallons with gauge reading half a tank. I have the standard 26 gallon tank. Dash said the fuel mileage was 16.7. Total miles driven was 312. My calculator says that's 21.3 mpgs, not 16. The truck normally falls in the 20+ mpg range as I drive hiway mostly but so far it's been mixed with some town driving.One thing I did notice. Sitting at a light really hammers the dash mpgs. It can fall an easy .5-.7 mpgs at just one normal traffic light. Seems like a lot even at the end of the tank. I can see it fall at the very beginning but not at the end.
 
  #12  
Old 06-27-2015, 01:22 AM
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this is the last time i actually checked my reciept with the truck. 1/2 the miles was running empty, other half was pulling a 16' trailer back running 65/70.

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  #13  
Old 06-28-2015, 08:19 PM
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Originally Posted by Labnerd View Post
...One thing I did notice. Sitting at a light really hammers the dash mpgs. It can fall an easy .5-.7 mpgs at just one normal traffic light. Seems like a lot even at the end of the tank. I can see it fall at the very beginning but not at the end.
If you reset the gauge at every fill up this is certainly the case. If you go long periods of time between them it doesn't change since the sampling period is much longer.

What a lot of people fail to realize is that sitting still with the engine running is the worst MPG possible. You are going 0 miles but still using gallons. If you were to put your foot to the floor once the light turned green your mileage would actually go up. Since you would now be getting 2-3 MPG instead of 0.
 
  #14  
Old 06-29-2015, 01:18 PM
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Man, KingRanch, your '13 seems to be right on! By the way, I love ye truck!! King Ranch - man, that's me dream F150!
 
  #15  
Old 12-14-2015, 06:36 PM
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fuel used data wrong

I have the same problem. Traded a 2012, the info on that truck was right on the money, the 2015 is off about 10% At fill up says I have used about 19 gallons but takes 22 to fill it. ^ refills now.
 

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