Actual vs Indicated MPG
#136
01-09-2017, 11:05 AM
Fleet Mechanic
The sticker MPG on my new truck said it would get 18MPG in the city and 21 on the road. It doesn't do that. On my 2010 the numbers were 14 and 18 but the calculated average number for 143,000 miles was 13.64.
If the Fed EPA numbers are meant only as a comparator with other vehicles and not as an indication of what a new owner should expect then it would seem that a different measurement should be used
BB
If the Fed EPA numbers are meant only as a comparator with other vehicles and not as an indication of what a new owner should expect then it would seem that a different measurement should be used
BB
Even for the hwy ratings....some people consider their hwy use to be State Highways with max speed limits of 55-60mph. My interpretation of hwy use, here in Texas, are Interstates with speed limits of 75mph (everyone runs closer to 80). I bet there is a 20%++ drop of mpg at 80 vs 55mph.
What I am politely trying to say is that they can't take everything into consideration, so they throw out these estimates to us. Sure, it helps to give some indication of what you may see, but you may be disappointed if you consider it a guarantee.
#137
07-15-2018, 07:59 PM
But, 
doesn't want to fix it. Why should they? We have lots of people on here quoting what the LoM says for what MPG they are getting. So Mine was 10% to 12% optimistic. I applied 11% Fix, using the formula. Now it is perfectly close +-1%.
Imperial Formula: Calc MPG / Display MPG x1000=nnnn
Mine is 2018 Lariat 502A EB. I am just guessing it is very similar for older trucks.
By the North American (USA, Canada) Law Average Fuel Economy Display is not required to be accurate. Originally after Factory set up it is usually optimistic. The manufacturers love that. The Dealerships are told do not touch it. In EU by the Law it must be accurate. That’s why they came With Average Fuel Economy Display Correction Factor. Ford Version is “AFE Bias”. VW, Audi, BMW, Mini, GM, Mercedes have this as well. It is in the Software and waits for adjustment.
Do not waste your Time going to the Dealerships only to hear “too many variables”, “your foot is heavy on gas pedal”, “Weather conditions” and more...
I just did it and it feels good!!!
There is little Difference for XLT and LCD Cluster (Lariat and up) how to go to Engineering Menu.
Last edited by agmbg; 07-16-2018 at 10:35 PM. Reason: Incorection
#138
07-15-2018, 08:09 PM
There are only two variables involved in calculating MPG; miles and gallons. If the hand calculation and the cluster are using the same miles, then the only difference is the gallons.
Further, based on what I've seen on this forum, almost all the trucks are fairly consistent with about a 5% error. That should be an easy fix.
Further, based on what I've seen on this forum, almost all the trucks are fairly consistent with about a 5% error. That should be an easy fix.
Mine was 10% to 12% optimistic. I applied 11% Fix, using the formula. Now it is perfectly close +-1%.
Imperial Formula: Calc MPG / Display MPG x1000=nnnn
Mine is 2018 Lariat 502A EB. I am just guessing it is very similar for older trucks.
By the North American (USA, Canada) Law Average Fuel Economy Display is not required to be accurate. Originally after Factory set up it is usually optimistic. The manufacturers love that. The Dealerships are told do not touch it. In EU by the Law it must be accurate. That’s why they came With Average Fuel Economy Display Correction Factor. Ford Version is “AFE Bias”. VW, Audi, BMW, Mini, GM, Mercedes have this as well. It is in the Software and waits for adjustment.
Do not waste your Time going to the Dealerships only to hear “too many variables”, “your foot is heavy on gas pedal”, “Weather conditions” and more...
I just did it and it feels good!!!
There is little Difference for XLT and LCD Cluster (Lariat and up) how to go to Engineering Menu.
Last edited by agmbg; 07-16-2018 at 10:33 PM. Reason: Incorection
#139
07-15-2018, 08:13 PM
Reviving an old thread because I "think" I may have stumbled on the method for fixing the displayed MPG.
There is a new thread about the "Engineering Test Mode" (https://www.ford-trucks.com/forums/1...test-mode.html), and while most of the data displayed is fairly routine, there is one value that is displayed that I think we can use to fix this issue. To get to "Engineering Test mode", you press the OK button on the steering wheel while turning the ignition to ON. Then you can cycle through all the values that it will display.
About half way through all the various different displays, you will come upon one called "AFE BIAS/AFE". The "AFE BIAS" is value that needs to be changed to fix how the truck calculates fuel used.
Now I'm not sure if the value needs to be adjusted up or down, but I'm guessing that it needs to be adjusted up (to increase the amount of fuel that it thinks you're actually using). So if your displayed value is off by 5% (which seems to be typical), then I would suggest that you have your service department set the AFE BIAS to 1050 (an increase of 5%).
I'm going to get this adjusted the next time I take my rig in for service.
There is a new thread about the "Engineering Test Mode" (https://www.ford-trucks.com/forums/1...test-mode.html), and while most of the data displayed is fairly routine, there is one value that is displayed that I think we can use to fix this issue. To get to "Engineering Test mode", you press the OK button on the steering wheel while turning the ignition to ON. Then you can cycle through all the values that it will display.
About half way through all the various different displays, you will come upon one called "AFE BIAS/AFE". The "AFE BIAS" is value that needs to be changed to fix how the truck calculates fuel used.
Now I'm not sure if the value needs to be adjusted up or down, but I'm guessing that it needs to be adjusted up (to increase the amount of fuel that it thinks you're actually using). So if your displayed value is off by 5% (which seems to be typical), then I would suggest that you have your service department set the AFE BIAS to 1050 (an increase of 5%).
I'm going to get this adjusted the next time I take my rig in for service.
Mine was 10% to 12% optimistic. I applied 11% Fix, using the formula. Now it is perfectly close +-1%.
Imperial Formula: Calc MPG / Display MPG x1000=nnnn
Mine is 2018 Lariat 502A EB. I am just guessing it is very similar for older trucks.
By the North American (USA, Canada) Law Average Fuel Economy Display is not required to be accurate. Originally after Factory set up it is usually optimistic. The manufacturers love that. The Dealerships are told do not touch it. In EU by the Law it must be accurate. That’s why they came With Average Fuel Economy Display Correction Factor. Ford Version is “AFE Bias”. VW, Audi, BMW, Mini, GM, Mercedes have this as well. It is in the Software and waits for adjustment.
Do not waste your Time going to the Dealerships only to hear “too many variables”, “your foot is heavy on gas pedal”, “Weather conditions” and more...
I just did it and it feels good!!!
There is little Difference for XLT and LCD Cluster (Lariat and up) how to go to Engineering Menu.
Last edited by agmbg; 07-16-2018 at 10:30 PM. Reason: Incorection
#140
07-15-2018, 08:22 PM
Well guys. I took Kahuna in for its 12K mile service. In addition to the usual, I also had them apply the TSB for the harsh 5->4 downshift, and requested that they adjust the MPG display. They refused, and came back with this from Ford corporate (excuse any typos, I transcribed it from the service report):So they claim that just the tire diameter will affect this reading. I think this is bogus, as the miles traveled by the vehicle are the same regardless of whether the mileage is hand calculated or used by the cluster. Am I wrong on that count?
If I can get my hands on a diagnostic plug-in, I will start messing with the AFE BIAS on my own to see what happens.
If I can get my hands on a diagnostic plug-in, I will start messing with the AFE BIAS on my own to see what happens.
Mine was 10% to 12% optimistic. I applied 11% Fix, using the formula. Now it is perfectly close +-1%.
Imperial Formula: Calc MPG / Display MPG x1000=nnnn
Mine is 2018 Lariat 502A EB. I am just guessing it is very similar for older trucks.
By the North American (USA, Canada) Law Average Fuel Economy Display is not required to be accurate. Originally after Factory set up it is usually optimistic. The manufacturers love that. The Dealerships are told do not touch it. In EU by the Law it must be accurate. That’s why they came With Average Fuel Economy Display Correction Factor. Ford Version is “AFE Bias”. VW, Audi, BMW, Mini, GM, Mercedes have this as well. It is in the Software and waits for adjustment.
Do not waste your Time going to the Dealerships only to hear “too many variables”, “your foot is heavy on gas pedal”, “Weather conditions” and more...
I just did it and it feels good!!!
There is little Difference for XLT and LCD Cluster (Lariat and up) how to go to Engineering Menu.
Last edited by agmbg; 07-16-2018 at 10:34 PM. Reason: Incorection
#142
07-15-2018, 10:13 PM
Fleet Mechanic
Gentlemen!
This is easy Fix. Go to "Engineering test menu". Find "AFE Bias". Replace 1000 Number with the Number from the Formula: Calc MPG/Display MPG x 1000=nnnn
Mine was 10% to 12% optimistic. I applied 11% Fix, using the formula. Now it is perfectly close +-1%.
Mine is 2018 Lariat 502A EB. I am just guessing it is very similar for older trucks.
By the North American (USA, Canada) Law Average Fuel Economy Display is not required to be accurate. Originally after Factory set up it is usually optimistic. The manufacturers love that. The Dealerships are told do not touch it. In EU by the Law it must be accurate. That's why they came With Average Fuel Economy Display Correction Factor. Ford Version is "AFE Bias". VW, Audi, BMW, Mini, GM, Mercedes have this as well. It is in the Software and waits for adjustment.
Do not waste your Time going to the Dealerships only to hear "too many variables", your foot is heavy on gas pedal", "Weather conditions" and more...
I just did it and it feels good!!!
There is little Difference for XLT and LCD Cluster (Lariat and up) how to go to Engineering Menu.
I can assist with the best of my Knowledge.
This is easy Fix. Go to "Engineering test menu". Find "AFE Bias". Replace 1000 Number with the Number from the Formula: Calc MPG/Display MPG x 1000=nnnn
Mine was 10% to 12% optimistic. I applied 11% Fix, using the formula. Now it is perfectly close +-1%.
Mine is 2018 Lariat 502A EB. I am just guessing it is very similar for older trucks.
By the North American (USA, Canada) Law Average Fuel Economy Display is not required to be accurate. Originally after Factory set up it is usually optimistic. The manufacturers love that. The Dealerships are told do not touch it. In EU by the Law it must be accurate. That's why they came With Average Fuel Economy Display Correction Factor. Ford Version is "AFE Bias". VW, Audi, BMW, Mini, GM, Mercedes have this as well. It is in the Software and waits for adjustment.
Do not waste your Time going to the Dealerships only to hear "too many variables", your foot is heavy on gas pedal", "Weather conditions" and more...
I just did it and it feels good!!!
There is little Difference for XLT and LCD Cluster (Lariat and up) how to go to Engineering Menu.
I can assist with the best of my Knowledge.
I’m searching YouTube for how to actually change the number.
#143
07-16-2018, 02:01 PM
start with engine off , ignition off.
press ok button on steering wheel and hold.
turn ignition on. No start.
when engineering mode appears, toggle using the arrows to the screen that has the AFE bias. It will have the 1000/ and a mpg.
toggle left or right to adjust the bias. I went with 0941 as it computes from 16 mpg actual, 17 mpg indicated.
I pressed ok, not sure if you need to. It went to the next screen. I toggled back to make sure my 0941 was still in place. It was and I turned off the truck.
when we left the store, and drove home, my truck was always within .2 of my Scanguage . At times it was exactly the same.
I'm really disappointed that the dealerships will not do this for buyers of new trucks. I now have to believe that it's not done so that the buyer can be deceived about the true mpg of these trucks.
#145
07-16-2018, 04:34 PM
ignition off.
press ok on the steering wheel, and hold.
ignition on and continue to hold ok until the menu appears.
#147
07-16-2018, 04:43 PM