William_Canada Posted January 4, 2011 Report Share Posted January 4, 2011 Do you guys find the same problem that the Edge MPG indicator is higher than the actual MPG? My car is Ford SEL AWD 2010. And I bought it 3 weeks ago. Right after I got the car, I filled up the tank and reset the MPG indicator. Yesterday I filled up the second tank. The car indicator shows the average MPG is 10.9L/100km. While my own calculation is 12.5L/100km. Why is there such a big difference? Quote Link to comment Share on other sites More sharing options...
akirby Posted January 4, 2011 Report Share Posted January 4, 2011 Do you guys find the same problem that the Edge MPG indicator is higher than the actual MPG? My car is Ford SEL AWD 2010. And I bought it 3 weeks ago. Right after I got the car, I filled up the tank and reset the MPG indicator. Yesterday I filled up the second tank. The car indicator shows the average MPG is 10.9L/100km. While my own calculation is 12.5L/100km. Why is there such a big difference? 1 - the gas pump calibration may be off. 2 - you never get exactly the same amount of fuel in the tank each time 3 - there was an error in your calculation somewhere That's only a 15% difference but it's usually closer than that. I would keep track of it for a few more tanks before starting to worry. Also try getting fuel from a different station if possible. Quote Link to comment Share on other sites More sharing options...
William_Canada Posted January 4, 2011 Author Report Share Posted January 4, 2011 1 - the gas pump calibration may be off. 2 - you never get exactly the same amount of fuel in the tank each time 3 - there was an error in your calculation somewhere That's only a 15% difference but it's usually closer than that. I would keep track of it for a few more tanks before starting to worry. Also try getting fuel from a different station if possible. 1 - the gas pump calibration may be off. That is too bad as I pay according to the gas pump indication. 2 - you never get exactly the same amount of fuel in the tank each time I don't it would affect my calculation much, please refer to my method in the following. 3 - there was an error in your calculation somewhere My calculation method: I filled up the tank after I bought the car, and reset the trip meter. Then I recorded how much gas I put until yesterday I filled up the tank again. Then I divided the gas volume with the trip meter reading. The only problem could be is that "get exactly the same amount of fuel in the tank each time". But only the last time fillup could be affected, and it should be minor difference. So I still cannot explain the 15% off. Quote Link to comment Share on other sites More sharing options...
akirby Posted January 4, 2011 Report Share Posted January 4, 2011 1 - the gas pump calibration may be off. That is too bad as I pay according to the gas pump indication. 2 - you never get exactly the same amount of fuel in the tank each time I don't it would affect my calculation much, please refer to my method in the following. 3 - there was an error in your calculation somewhere My calculation method: I filled up the tank after I bought the car, and reset the trip meter. Then I recorded how much gas I put until yesterday I filled up the tank again. Then I divided the gas volume with the trip meter reading. The only problem could be is that "get exactly the same amount of fuel in the tank each time". But only the last time fillup could be affected, and it should be minor difference. So I still cannot explain the 15% off. I agree it shouldn't be off by that much but if you consider that the pump, the fuel tank top off and the on board computer estimate could each be off by 5% that adds up to a 15% difference. I still wouldn't worry about it yet - give it time to break in and settle down and recheck it. Quote Link to comment Share on other sites More sharing options...
ablb Posted January 4, 2011 Report Share Posted January 4, 2011 Do you guys find the same problem that the Edge MPG indicator is higher than the actual MPG? My car is Ford SEL AWD 2010. And I bought it 3 weeks ago. Right after I got the car, I filled up the tank and reset the MPG indicator. Yesterday I filled up the second tank. The car indicator shows the average MPG is 10.9L/100km. While my own calculation is 12.5L/100km. Why is there such a big difference? YEP… You’re not alone. I have hand calculated our MPG almost every tank. Every once in a while they will come out the same. And I distinctly remember the car actually getting better than I hand calculated a couple of times. BUT for the other 138 of 148 recorded fill ups the MKX DOES NOT get as good as IT SAYS it does! We’re at 43K miles now and are about to buy new tires OEM Pirelli’s do 702 revolutions per mile The Yokohama’s we’re looking at only do 698. SO I’m expecting a change, not sure which way? ab Quote Link to comment Share on other sites More sharing options...
L1TECH Posted January 5, 2011 Report Share Posted January 5, 2011 I have never owned a vehicle where the mpg calculation that was done by the car was accurate. The only vehicle that I have owned that came close to what it said was my Lexus IS350, and it was consistantly off by 1.2 mpg. On my Ford Sport Trac the mpg was always about 2 mpg higher than calculated and on my Edge it is always about 1.5 mpg higher than calculated. I get gas at only one gas station and I do actually use the same pump all the time. I look at it this way, if the vehicle actually were able to calculate the true mpg that you were getting do you know how many vehicles would be in the shop because people complained about lower than advertised mpg...alot 1 Quote Link to comment Share on other sites More sharing options...
akirby Posted January 5, 2011 Report Share Posted January 5, 2011 I have never owned a vehicle where the mpg calculation that was done by the car was accurate. The only vehicle that I have owned that came close to what it said was my Lexus IS350, and it was consistantly off by 1.2 mpg. On my Ford Sport Trac the mpg was always about 2 mpg higher than calculated and on my Edge it is always about 1.5 mpg higher than calculated. I get gas at only one gas station and I do actually use the same pump all the time. I look at it this way, if the vehicle actually were able to calculate the true mpg that you were getting do you know how many vehicles would be in the shop because people complained about lower than advertised mpg...alot You really have to consider how the vehicle computer does this calculation. Mileage is easy as that's already built in with the odometer, but how does it know how much fuel has actually been used? The only way I can guess is that it counts the number of injector pulses and multiplies that by the amount injected to get the total fuel usage. I don't see how that method could ever be accurate to less than 1 mpg just because of the way it's calculated and the minor variations in fuel injectors no matter how precise they are. We're only talking about a 3%-5% difference here. Quote Link to comment Share on other sites More sharing options...
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