Hybrid MPG gauge too high by 5.6%

[Master Blaster]

No.
This is a myth, a long held myth but a myth none the less.

Gas is held underground where the temperature changes very little year round.

A pump in Duluth MN will be calibrated a little differently than a pump in Phoenix, AZ since their ground temperatures are a little different.
But the Duluth pump is consistent year round as is the Phoenix one. Within a penny per tankful.

If its a myth, then why did I get 18 gallons into a 17 gallon tank on my 87 Ranger? It P.O.ed me so much that I refuce to deal with that fuel company to this day. Its not a myth, and you've just been lucky that you filled up a a place that probably was not doing it.

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[Bill Quattlebaum]

I can't speak for the hybrid, but on my Ecoboost, the setting of 950 seems to work very well. Like others have said the factory setting is 5 to 6 percent too high.

 

[huunvubu]

Yes

Yes it is intentional because everyone who tracks MPG as close as you do, including myself comes to the same conclusion that the factory setting always is 5% optimistic, or a tad more, I'm gonna say 5.5% in mine.... if monitor closely and take the long term average.

Yes you can fix this

Very few software parameters are user adjustable but Ford made the fuel economy formula easy for the lay person to adjust.

Look online for "engineering test mode" and AFE (average fuel economy) adjustment.

There is a "correction factor" anyone can adjust at home. No tools. Just button presses.

The correction factor is set to 1.000

Expressed as 1000/1000

You can change the numerator.

In your case and mine 945/1000 would take the MPG and multiply it by 945/1000 or, be a 5.5% reduction.

Now, what I see on the dash matches what I see at the pump.

Of course all your "miles to empty" estimates are now that much better too.

https://www.mavericktruckclub.com/f...t-via-engineering-test-mode.58342/post-983941

The instructions for entering "Engineering Test Mode" in your posted link did not work for me.

These instruction did work on my 2023 Ford Maverick XLT Hybrid

Ford Maverick Engineering Test Mode!!! [How to Enter]

1. Enter Truck
2. Put on Driver Seat Belt
3. Lock Truck using Key Fob
4. Hold "OK" Button and turn Key to Start Truck and continue to Hold "OK" button until Green "ET" is shown on center screen

 

[lm126027]

I’ve noticed my % of actual mpg in relationship to the displayed mpg varies depending on the gas station I fill up at. I always set the pump handle to the lower setting and once it stops, I don’t fill up anymore. I suspect some stations have a lower sensor or higher sensor depending on the nozzle. At some fillups my discrepancy is only 1.5% while at other fillups it’s been as high as 7%. I know I’m measuring correctly and repeating the same process every time. To me the only variable is the pump. It can’t be the varying outside temperature (etc) since this is a shared factor that plays out in BOTH the actual and displayed mpg—so it wouldn’t explain fluctuations in % discrepancy between actual and displayed.

Thoughts?

Not thought of that, but seems realistic. Last week did a 944 mile, 17.5 hour round trip drive to northern Maine from MA to pick up my snowmobile that had broken down and left at a dealership to be fixed. The amount of fuel I put in varied a lot at one station even though the miles to empty were very close. I always hit the filler one more time after it stops. 1st stop was 15.22 gallons (EB with 16 gal tank) with 15 miles to empty. Several other stops with around 25 miles to empty all put 13 something (1/4 to 1/2 gallons). Rather odd that one station was that much different (2 gal) than the others. All but one were Irving stations. I was pulling my 13', 90 inch high and wide trailer, empty on the way up and with one 4 stroke snowmobile on the way back. Cruise set at 72 in MA and NH, and 75 in Maine (where posted is 70 in the lower part of the state and 75 after Bangor). Average mileage showed 13.3 in the car with 13.122 when calculated. One of the closest calculations I have seen since I got the truck the end of September, though have maybe only done the hand calculations a dozen or so times. Truck now has over 10,000 miles.

 

[DWV]

Check a few more tanks as you gain mileage, then change the % in engineering mode.
I experienced the same about 5% difference, over corrected and then zeroed in. Last change was to about 97% or maybe 96.5%- forgot to write it down, but it is quite close on the last 2 tanks.

I don't drive a lot, so I would use 1/2 a tank and fill and calculate, I try to use the same pump at the same station each time as it will make a difference as mentioned above.

 

[MetalsGeek]

Gas station fuel pumps are supposed to have temperature compensation built-in. The internet says (?) 87 octane E10 should weigh around 6.33 lbs/gal. The gas sold in my local area measures out at 6.15 lbs/gal so it's either less dense or the stations I use are screwing me 3%. LOL Whatcha gonna do?
My XLT hybrid MPG has averaged mid-40s and originally reported around 4.4% high so our experiences agree pretty well. Here's how I enter Engineering Test Mode:

- Hold your foot on the brake pedal. (door and seat belt don't seem to matter)​

- Hold the OK button on the steering wheel >5 sec before inserting key.​

- Switch ignition to "RUN" (OFF-ACCY-RUN-START).​

- Continue holding OK until green "ET" appears in dash display at top right. (~ 15 sec)​

- Use OK & MENU buttons to explore​

The reported MPG is tuned via the AFE Bias, which defaults to 1000. I set mine to 958 for starters, but circumstances have temporarily interfered with my ability to determine whether this will be a good "final" value.
One more tip: It took me a long time to figure out how to force an engine start so I could do a leak check after changing the oil. Leave it in Park and stomp on the accelerator. Soooo easy. My dealer said it could not be done.

 

[MaverickDragon]

Gas station fuel pumps are supposed to have temperature compensation built-in. The internet says (?) 87 octane E10 should weigh around 6.33 lbs/gal. The gas sold in my local area measures out at 6.15 lbs/gal so it's either less dense or the stations I use are screwing me 3%. LOL Whatcha gonna do?

One measured gallon of fuel will vary in weight by temperature just like any liquid which expands with heat and shrinks when cold and fuel also varies by the addition and quantity of additives which can contribute to an increase or reduction in weight depending on formulation.
Ethanol is about .4 pounds per gallon heavier than gasoline, so a less than 10% ethanol will reduce the weight of the measured gallon.

Atmospheric pressure is also a factor, albeit minor.

A gallon of regular 87 octane E10 gasoline should weigh approximately 6.073 pounds at 75 degrees Fahrenheit. The same fuel at 50 F would weigh 6.1 pounds, again with additive variation, and assuming an equivalent percentage of ethanol.

The weight you noted sounds about right except for the weight you thought it should be.
Fuel that weighs less may just be more actual gasoline than ethanol, which could be a plus.

 

[Cherokee]

My Ecoboost’s indicated mpg’s are about 10% off.
Ford’s not fooling me.
I get 26 mpg for a long term average from checking the old fashioned way.

They do this to sell stuff and to meet Guv requirements. You can’t tell me they couldn’t have been extremely accurate on mpg’s.

I don’t waste my time on things like that.

In my NOT so humble opinion all this electronic crap and most of the bells and whistles are as useful as hen shit on a pump handle.

I miss my 1984 Ranger
And my 2006 Taco

 

[MaverickDragon]

My Ecoboost’s indicated mpg’s are about 10% off.
You can’t tell me they couldn’t have been extremely accurate on mpg’s.
I don’t waste my time on things like that.

Okay, I'll tell you - They could be extremely accurate on mpg’s, and with a tweak they can be, if they are not already.
OTOH
It may not be in their best interest to display a lower though accurate number as many (most?) just take the infotainment gauges at face value. A better mpg number might make the customer feel better.

There is no mandate I'm aware of that requires their gauges and calculated displays to be accurate, but their reported EPA numbers (mostly which manufacturers report themselves) can cause problems if they are very far off, and that is based on how the test is run, which is for comparison purposes only, as virtually no one drives the way the tests are performed.

Apparently, I waste my time on things like that.

In the case of my truck (YMMV) where I get fuel at the same pump at the same station, parked in the same orientation in the same spot for the last 5 or 6 tanks, the fuel use I calculate using the mpg and mileage figures on the display for trip 2 that I use for fuel calcs, coincides very closely (+/- a tenth or two) with the fuel shutoff on the pump (first click).

For those who discern a significant difference between reported vs calculated, the algorithm can be changed to make the two figures match.

 

[MetalsGeek]

One measured gallon of fuel will vary in weight by temperature just like any liquid which expands with heat and shrinks when cold and fuel also varies by the addition and quantity of additives which can contribute to an increase or reduction in weight depending on formulation.
Ethanol is about .4 pounds per gallon heavier than gasoline, so a less than 10% ethanol will reduce the weight of the measured gallon.

Atmospheric pressure is also a factor, albeit minor.

A gallon of regular 87 octane E10 gasoline should weigh approximately 6.073 pounds at 75 degrees Fahrenheit. The same fuel at 50 F would weigh 6.1 pounds, again with additive variation, and assuming an equivalent percentage of ethanol.

The weight you noted sounds about right except for the weight you thought it should be.
Fuel that weighs less may just be more actual gasoline than ethanol, which could be a plus.

Speaking theoretically is all well and good, but it would be interesting for you to actually go out and buy 1.000 gal from your local station, weigh it, and measure its temperature to see how your own real-world data point fits. Don't see how atmospheric pressure would have a measurable effect...

 

[Mavster Mechanic]

Speaking theoretically is all well and good, but it would be interesting for you to actually go out and buy 1.000 gal from your local station, weigh it, and measure its temperature to see how your own real-world data point fits. Don't see how atmospheric pressure would have a measurable effect...

Ya.

Measuring ONE gallon is not very accurate. How do you know you got exactly one gallon? Also, some evaporates by the time you put it on the scale. And how good is your scale? And how do you know?

 

[DWV]

Non of this is new news! Subject has been beaten to death in many threads.
The method to correct the read out is present.

 

[MaverickDragon]

Speaking theoretically is all well and good, but it would be interesting for you to actually go out and buy 1.000 gal from your local station, weigh it, and measure its temperature to see how your own real-world data point fits. Don't see how atmospheric pressure would have a measurable effect...

Sure, sounds like an easy experiment... NOT.
Testing a thousand gallons doesn't increase test accuracy.

Temperature and pressure affect the fuel volume measured to a greater and lesser degree, and the measurement of a delivered gallon may also vary slightly especially if the pump or container being used to measure the volume hasn't been calibrated.

There are variables that change the weight of a gallon of fuel, so your conclusion of being ripped off because you think that the gas you weighed should weigh 6.33 pounds per gallon isn't true. There is no single standard number for E10 fuel weight - It's a range of values due to the variables.

Standard weight listing ranges for E10 87 regular gasoline is 6.1 to 6.33 pounds, so what you measured at 6.15 seems to be right in spec.
Find a different windmill.

 

[MetalsGeek]

Sure, sounds like an easy experiment... NOT.
Testing a thousand gallons doesn't increase test accuracy.

Temperature and pressure affect the fuel volume measured to a greater and lesser degree, and the measurement of a delivered gallon may also vary slightly especially if the pump or container being used to measure the volume hasn't been calibrated.

There are variables that change the weight of a gallon of fuel, so your conclusion of being ripped off because you think that the gas you weighed should weigh 6.33 pounds per gallon isn't true. There is no single standard number for E10 fuel weight - It's a range of values due to the variables.

Standard weight listing ranges for E10 87 regular gasoline is 6.1 to 6.33 pounds, so what you measured at 6.15 seems to be right in spec.
Find a different windmill.

If you look again, you will see that I said 1.000 and not 1,000. (3 digits past decimal to imply precision on the pump display) The rest really is easy peezy if you have a scale and remember to measure the tare weight of the can before filling up. A thermometer and graduated cylinder will round out your gear to check pump calibration as well as the dept of weights and measures. If you want to measure the alcohol fraction as well, the process is really simple since alcohols are soluble in water but gasoline is not. The graduated cylinder does that too. We learn things from actually doing that armchair Googling can't teach.
Your comment on the compressibility of liquid gasoline under barometric pressure changes is interesting. Admittedly, it is twice as compressible as water, but really...?

 

[kevink]

If its a myth, then why did I get 18 gallons into a 17 gallon tank on my 87 Ranger? It P.O.ed me so much that I refuce to deal with that fuel company to this day. Its not a myth, and you've just been lucky that you filled up a a place that probably was not doing it.

Which would indicate that the gas was about 83 degrees cooler than normal for thermal contraction to account for this.

Or there was a pump issue.

Earlier this year I put in an "impossible" amount of gas into my car at a pump. The gauge said I had about 1/3 of a tank when I started and I put in nearly the rated tank amount in. But it was ALSO one of those days that the pump was going REALLY slow. I should have stopped it right away. The chain, owned by 7-11, blew me off. I have not bought anything from that chain since.

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