This may be old news to most but just in case...

I recently bought a new 2019 F150 with the 3.5 ecoboost. The on board computer shows it getting 19.2 mpg over the life of the truck so far, a little over 6000 miles. I hand calculated the milage today and found the on board computer, affectionately known as the lie-o-meter, overstated my gas milage by 6.7%. Granted, considering the performance, the hand calculated milage is still darn good, especially compared to my previous truck, a ‘10 Tundra with the 5.7L V8.

Anyway, I got to do a little reading on this and found the MPG calculation is notoriously optimistic in these trucks, but I also found that it can be corrected with an easily accessible setting in the engineering mode of the computer.

To access the engineering mode, press and hold the OK button on the steering wheel while turning the key to the second notch without starting the truck. You’ll have a bunch of funny looking settings in your display. Scroll down until up you get to AFE BIAS. Press OK to access it then scroll down or up as necessary to edit the bias to the correct number. To get the correct AFE BIAS, divide your hand calculated milage by the vehicle displayed milage and multiply that by 1000. Once you’ve entered the bias, turn off the ignition key. When you turn it back on, you will see that the vehicle displayed mpg matches what you calculated.

It’s irritating that Ford has the ability to make these readings accurate but chooses not to but at least they provided us the means to correct it.

John

Tag for reference

I’m guessing all the manufacturers do that.

Tag

Have you checked your speedo and odometer for accuracy? That is usually the cause of it

It’s so you can change it to read great mpg when you sell it to dupe the next fool.

a better idea

Even hand calculations have a variance in accuracy, the pump doesn't always stop at the exact same amount every time, even on the same pump. Hard to say which method is actually more accurate without some seriously accurate testing equipment.

My 2016 F150 eco boost got 32 mpg on the highway. I know that is true.

You have to calibrate the onboard computer to match your driving style. I've put over 70,000 miles on mine and it has never been off by more than 1/2 mpg. And it reads over almost as often as under. I guess the way I drive pretty well matches the factory settings. We also have a Honda with that feature. It is always optimistic, and often by 4-5 mpg compared to hand calculations.

https://apps.apple.com/us/app/id557871911

This is pretty handy

2017 f250 with 6.7 psd, trip computer is typically only 1 mpg less than hand calculated, guess I lucky

It is a real mistake to automatically assume the vehicle computer is the source of error. Depending on the state, pump measurements are only checked every few years.

Growing up working in a gas station and watching pumps checked for accuracy, the standard to pass allowed for a 3% error on the pump. The guage used to check accuracy looked like an old 5 gallon milk bucket with a sight glass on the side and plenty of dents decreasing volume a bit more. Some stations can go years between accuracy checks.

In contrast, trucks now have computer controlled fuel/air mixtures, which are in a position to make some accurate measurements of fuel going to injectors. Of course, a computer programmer can massage the numbers as VW showed. Also some fuel can be lost to venting or leaks, which is not measured as going to the injectors.

Over time filling up at brand new stations just opening, the pump and vehicles numbers match almost perfectly. The biggest gaps are at stations with old pumps and unusually low prices.

Now I consider the vehicle computer to an indicator of how bad the pump is ripping me off.

Oh no........It's Volkswagen all over again!

I’m wouldn’t have an ecoboost if they gave it to me. My F-150 does just fine with the 5.0L. Better than half of my friends that have had eco boost trucks have traded em back in.

They do. . . .

Then again, most new vehicle buyers these days base
their purchase on the trim level of the interior, and the electronic gadgetry in the dash. That's one of the reasons you don't see any " old man " trucks like used to be so common in the " old days " with a standard transmission and vinyl bench seat and floor mat. Without all the diamonds to dazzle the owner, they'd see how cheaply vehicles are built these days. Half the front end on all these trucks nowadays is fragile plastic stuff that's nearly guaranteed to crumble with hard use and exposure to the elements. How many will still be serviceable in 40-50 years?

Most of the good old trucks never made 100000 miles and some of the new ones make 300000 plus. Old is old. Ed k

My speedometer is pretty much perfect, matching GPS digit for digit.

John

My 2011 F150 mileage calculator is spot on. I never trusted those things until this truck but everytime I check my mileage its within a 1/2 gallon of the computer. If my odometer settings says 12.3 gallon that is what it will take to fill it back up. But im sure they have changed things since 2011. My speedometer is off about 4 mph though.

Ed, up here most folks consider 100,000 miles just nicely broken in.

Ted

You're right about that old is old but those classics sure look good and are still fun to drive. Here's mine, and I dont calculate the gas mileage, I just dont pass up a gas station.

My old truck a 93 Chevy went 327k till the oil line broke and ran out of oil...funny thing there was only one cyl that has some scoring deep enough to need bored 40 tho the other 7 would have cleaned at 10 ..the crank had one spun Bering so we turned the crank 10 under...if those oil lines hadn't broke that motor could have run a million miles...it was still running good ...it's back tho with a fresh rebuild..

I bought a 2015 F150 last August and going up north turkey hunting last week it registered 25.6 mph at a steady 60 mpg. I got gas 3/4 of the way and it calculated 23 mpg,- but I didn’t exactly fill it to the cap when I started nor when I refueled, so I don’t know how much difference there was.

I keep the display on the MPG indicator but this is basically a vacuum gauge.

I’ll print out the first post and see how it goes - my boy is a computer whiz and has already made some changes for me.

Bit of a side issue but Ted you may remember the one I had the last time you visited down this way. My 2004 blue & gray F-350 XLT Super Cab, diesel 4x4. Long story short, at 3:10am on the morning of May 11th, some individual stole it. He was caught, but the truck ended up being an I.C.B.C. write off and waiting for the settlement cheque. An experience that left my lady and I feeling a little vulnerable. May end up replacing it with a new Ford Ranger. That's about all I really need these days. :)Just nicely broken in, 215,000 km.

A little follow up. Filled up today and hand calculated milage. 17.94 mpg. The computer calculated 18.0 mpg. Pretty dang close. I’m thinking the fuel bias calibration worked like it’s supposed to but will continue to monitor.

John

My 5.4 says I'm getting 11.3 mpg. Must be getting 9.3 mpg.

Guess what? It's a truck, not a tercel. It gets crappy mileage.

What's the input for gallons of gasoline burned? If the input is the number of gallons in a full tank minus the number of gallons in the tank when you fill it, then you're depending on your tank gauge for accuracy.

Gasoline that is formulated differently
will also perform differently and may
require more foot in the throttle to
achieve the desired performance

And. . . It's still a truck

Miles traveled on that tank/number of gallons to fill it. Depends on gas pump accuracy and odometer accuracy. So far, the adjusted computer and hand calculation match within .3%

John

Interesting, as I hunt sometimes with a retired Ford engineer. We got to discussing fuel economy and calculations and he said that was the first thing to check, with a good GPS reading. Speedometer and odometer. Mentioned the factory settings are for the new tires, at the specified inflation, and I believe on an unloaded vehicle, leading to a given diameter. mentioned that as tires wear and diameter reduces, the numbers can be off some. Also said they calculated rolling diameter that way, not just mounted diameter as stated by the tire stores.

When he started to get into some minutia, I just shut up and listened as he sorta seemed to know what the heck he was talking about

No two trucks are going to get the same miles because we all don't drive the same. Cheers NC

I’m not as concerned with the milage as I am with stuff working like it’s supposed to. If the truck is going to display a fuel milage, then it should display an accurate fuel milage. It should do that as it comes from the factory but mine didn’t. At least they engineered in a way to correct it.

As far as fuel milage goes, I don’t expect a truck to compete with a car, but since my truck has to be my daily driver and I commute 60 miles each day to/from work, I’m happy to get better milage in my truck if I can. I’d rather spend those $800/month fuel bills on something else. So far, the F-150 is showing a significant savings over my Tundra, even with manual calculations on both. F-150 is averaging about 18. 5.7 Tundra averaged 14.7. So far, so good...

John

It's almost possible to accurately measure MPG because of many things like when the pump cuts off, accuracy of the gas pump (I once put 22 gal in a 20 gal tank), speedo accuracy, odometer accuracy and tire wear/tire air presure (effects speedo/odometer accuracy). You can get a ballpark number but I hear people all the time saying something like they 20.347 mpg on the highway driving 75 mph.

Must've measured your mileage from Bozeman to Livingston.

I'm not sure what the end goal is, nor keeping a running journal, but regardless, enjoy your endeavors, they sound like a fun time.

I can’t remember the last time I checked my gas mileage.

Thanks for posting this I'll send it to my son. His wife drives a Ford Explorer with the Ecoboost engine and she loves it. He told me they are getting a little over 20 mpg hand calculated, I don't what the computer says. Their previous Explorer had the 5.4 V8 and got horrible mpg. It also had expensive electronic problems.

Side question: How did you like your Tundra? I’ve read their mileage sucks, not as capable for hauling heavy load as Ford or Dodge, but is much better on maintenance. Is this match your experience?

What is Fords tolerance to that number? Maybe it’s greater than 6.7%, maybe there is no stated tolerance. How did you determine your odometer accuracy? How did you determine how accurately gas was dispensed in your tank every time you filled it? Just curious

Well, I am going to see if I can change the AFE in my 2500HD to get 18 or better rather than 12 and never hand calculate again to find it quite accurate...at least I will feel better about driving a gas sucking pig.

I had a Chevy with that, my main current ride is a Subaru Forester. (go ahead, bring on the gay jokes...LOL)

The Chevy mileage calculator was about 10 % optimistic. Subtract about 10 % of the reading and you were in the ballpark.

Subaru is in the 5-8 % range over what is achieved in real life.

If the Chevy said 30 MPH, it was more like 27. Subaru says 36, more like 34 or thereabouts. Most people are too lazy to figure the real mileage out.
Not to mention there would be some variance between gas pumps. I drive like the old man that I am, so it doesn't really matter with the 45 miles I drive per day during the week.

There's a lot of variables in play and it's not surprising that calculated mpg differs a bit from actual mpg. A 6.7% error is not bad for the default setting. It's good that you can adjust the reading to make it a closer match. In order for Ford to get it closer, they'd have to do what you did; run a couple of tanks of gas through it, calculate actual MPG and then do the adjustment. Needless to say that's not practical for every vehicle they make with an MPG computer.

Ignore the computer and Google "internal combustion engine thermal efficiency."

I had two different Tundras, a 2007 with the 4.7L and a 2010 with the 5.7. With the exception of the same major problem on both of them, they were extremely reliable. Both had air injection pump and air injection valve problems. The ‘07 was covered under warranty but the ‘10 was past that coverage so I traded it in on the F-150. Only 7300 miles on the F-150 so far so I don’t really know anything about its reliability but I can say that the 3.5 Ecoboost has more balls than the 5.7 Tundra did and pulls noticeably harder and gets noticeably better fuel milage. So far, so good.

Back to the Tundra reliability. We’re it not for the air injection problems, I’d have nothing bad to say about them. Neither consumed or leaked a drop of fluids between oil changes all the way up to the 185,000 miles where I parted with them.

John

The mileage calculator in my 2014 with the 3.5 Ecoboost is accurate if you fill up, then drive on the freeway and get off and fill up again. It doesn't calculate in idling and winter warm ups.

Ron

I got a plain jane XLT -2013 3.7 and never seemed to sniff that >20 mpg as advertised. My current tires are a bit larger than factory so I am wondering what I really am getting?

BTW- I got Cooper MTP's that are ridiculously good in mud but as loud as they are good. Gonna have to change em out.

"My current tires are a bit larger than factory so I am wondering what I really am getting?'

Why didn't you have your speedo corrected when you got larger tires (or do it yourself)?

States sometimes have someone who goes around to verify that a gallon sold is actually a gallon...
They check what once a year?

Does calculating or reading it actually change anything? When it gets low you fill up. When it’s below zero you fill up at half a tank. Simple. Ed k

I have the baby eco-boost motor. Mine reads 19.4 MPG and my hand calc'd MPG is 19.2. So, it's either pretty accurate or someone did your steps already. I've tried to find reasons to not like this motor. But so far, I can't.

Correct.

Love your truck sir!!