MPG Computer Accuracy

Discussion in '4th Gen - 2018 - present' started by Shutterbug57, Jul 3, 2019.

  1. Shutterbug57

    Shutterbug57 Member

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    Yesterday I took my first medium range trip in the new ‘19 Limited Max, 4x4, tow package. We did a quick round trip from Cincinnati to Knoxville and back. This was our third tank of gas and the first I have used to check the truck’s computer. I do reset the trip computer at each fill up.

    We left Cincinati with 138 in town miles on the trip meter and a computed average of 16.8 MPG. After going through Kentucky (hilly, but nothing serious) then up Jellico (a somewhat serious climb) and in to Knoxville then back to Lexington where I refilled, the Computer showed 21.1 MPG as the average for the tank. My computation after refueling was 19.7, or 1.4 MPG less than the computer. By necessity, I filled up at a different pump than the initial fill on this run, so that may make some difference. Also, as this is the first tank I have checked, I don’t have an established track record and this may or may not be indicative of long term performance of the computer.

    When I got home with just under 100 miles on the refilled tank, the computer was showing 23.4 MPG, which, if off by the same 1.4 MPG is still 22.0 MPG. I am not at all upset with the mileage I am getting. Further, I will hand compute MPG for a while to see if there is a trend with my Expi’s computer.

    I can’t say I have ever had a vehicle that was dead on with MPG calcs, but some have been closer than others. In most cases, the bias was fairly consistent. I am just curious what others are seeing with the accuracy of their on-board computer MPG numbers.
     
  2. jeff kushner

    jeff kushner Full Access Members

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    If you gather your 5 gallon can and fill it at various stations & pumps local to you, you will find a vast difference. I think they are allowed a 10% delta which I found to be true, one station only netting me 4.5 gallons! That's one full gallon in ten! None of them netted MORE than 5 gallons.

    I would only caution you to realize this, use the identical pump and give it a bit more time to balance out.....

    Very nice truck BTW!!

    jeff
     
  3. aggiegrad05

    aggiegrad05 Full Access Members

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    I’ve seen the same thing you have. After 21k mikes, the on-board computer says my lifetime average is 17.3, but hand calculations actually show 16.15 lifetime.
     
  4. Flexpedition

    Flexpedition Full Access Members

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    Whoa.

    Where I live the state weight & measurement dept. TWICE yearly checks each and every fuel dispensers.

    There are 231 cubic inches of liquid in a gallon.

    With a 5 gallon test can, plus or minus 6 cubic inches of fuel is the allowable variance.

    6 cubic inches is equal to roughly 6 tablespoons or 0.03 gallon.

    Over or under the 6 in^3 the station has 24 hours to repair. Pumps that exceed +/- 19 are locked down immediately.

    I'm pretty sure every state works similarly.

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    Last edited: Jul 3, 2019
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  5. Edwin C Aldredge

    Edwin C Aldredge Active Member

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    We don't have any trips on the Expedition yet, but our first is Sunday so I'm planning on tracking it then. On my Raptor I've found that over the life of the vehicle (20k so far) my dash is off by 1 mpg. Still running stock size tires, and a healthy amount of my driving is in the city. My overall average is currently 15.5mpg according to my fuel program, and 16.5mpg according to my dash.

    If the Expedition knocks down 22mpg on this trip, I'll be ecstatic!
     
  6. 16plati

    16plati Full Access Members

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    Let’s put it this way:

    Every time u reset the mpgs, how and where u drive for the first 100 miles or so will determine what ur readout will be.

    Example- I fill up, reset my mpg, and drive through my city for 100 miles it usually tops out around 15-16 mpg. Stop and go, red lights, traffic all negatively affect mpg on the ecoboosts

    I fill up, reset my mpg, and drive at 65 on the interstate for 100 miles I’ve seen it as high as 29mpg on my lifted and tuned 16 with 35s. I stay on the interstate at that speed and it will stay right around 28-29. The longer you drive with those consecutive high mpg numbers the slower the numbers will decrease as you move into the city. I always laugh when ppl worry about mpg in these 6000lb trucks. It’s worthless to worry about it bc you aren’t going to get good mileage. It’s plain and simple
     
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  7. aggiegrad05

    aggiegrad05 Full Access Members

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    This.
     
  8. Shutterbug57

    Shutterbug57 Member

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    I am not worried about MPG, I am amazed by it. I am getting basically the same mileage I got in my 6 cylinder 2012 Jeep Grand Cherokee. My ‘04 Armada got about 14 MPG over its life and struggled to get 16 MPG going down hill. I am elated with the numbers I am seeing on the Expi.
     
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  9. Iowan

    Iowan Member

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    Don't forget to check the odometer and speedometer for accuracy, both tend to be fast on Ford vehicles. A GPS app on your phone should do the trick.
     
  10. TobyU

    TobyU Full Access Members

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    I find them to be quite accurate.
     

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