2019 Ranger MPGs

chuck stein

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My lifetime fuel economy gauge reads 20.9 MPG, I however do 50/50 city to highway driving so I think that's pretty impressive. It obviously goes up after a long trip on the highway. Best was 26 mpg+ using cruise control.
The vehicle has a lifetime avg MPG's readout? Hmmm, where does it store all that data to calculate a "lifetime" number? Or, what math does it use to obtain this lifetime number?

And just for clarity, a lifetime avg is kinda meaningless. If you avg say 20MPG for 10yrs and then a bad sensor makes it run 18MPG, you'll never see that diff in the math used to get avg, etc.
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Gizmokid2005

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Why does the truck get better MPG's the more you drive it and the more dirty the engine components get? Is it because the tires are starting to wear down, or the catalytic converters are working better as they age?
Mostly because new vehicles need time to break in all the mechanicals and tolerances, so things loosen up a bit as they drive. Modern engines don't get that dirty with proper care, not enough to cause extra drag on the drivetrain.
 

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The vehicle has a lifetime avg MPG's readout? Hmmm, where does it store all that data to calculate a "lifetime" number? Or, what math does it use to obtain this lifetime number?

And just for clarity, a lifetime avg is kinda meaningless. If you avg say 20MPG for 10yrs and then a bad sensor makes it run 18MPG, you'll never see that diff in the math used to get avg, etc.
If you never reset the mileage calculator, you're essentially adding more and more data to that calculation. It doesn't necessarily save the data, it just keeps adding the instantaneous mileage to the calculation at the iteration it usually would (every 10 miles or whatever it does). I like to do that with Trip 2 stuff, never reset it and see where it goes, while resetting Trip 1 every fill-up.

The only reason you wouldn't see a relatively small and quick change like that is because it is just that, a small and quick change relative to all the large amount of data already used. It would change the average of course, but only by a minuscule amount. You don't use the lifetime average as a guide for anything.
 

RangerCoby

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Why does the truck get better MPG's the more you drive it and the more dirty the engine components get? Is it because the tires are starting to wear down, or the catalytic converters are working better as they age?
I don't know for sure. I've been told it has to do with the pistons/rings getting a little wear. It could also be the things you mentioned.

I would think this only applies to the "break in" period. I would imagine at some point the engine would get so much wear that MPG would start to decrease.

I'm sure someone with more knowledge will chime in regarding this.
 

DHMag

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My only gripe is my inconsistent mpg. While traveling, I get about 24mpg. Stop for gas, mpg drops to 20. About 80 miles into a full tank, the mpg starts to drop. Around 140 miles on the tank, it slowly comes up but then tanks around 180 miles.

I wonder if it's due to the fuel injector issue.
 


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My only gripe is my inconsistent mpg. While traveling, I get about 24mpg. Stop for gas, mpg drops to 20. About 80 miles into a full tank, the mpg starts to drop. Around 140 miles on the tank, it slowly comes up but then tanks around 180 miles.

I wonder if it's due to the fuel injector issue.
I've found that this engine is very susceptible to small variable changes. A slight head wind and it'll drop a few mpg. 5 mph faster and it'll drop a few mpg. Going up in elevation (even a very slight grade) and it'll drop a few mpg. "Bad" gas could be a contributor too. I usually try and get the same brand gas all the time, partly because I'm OCD and need that sort of consistency and order in my life, but also because I know different brands add or omit different treatments/chemicals (some of which I don't want in my vehicle), so that'll also affect engine efficiency. Not sure how much, but I'm sure it's not zero affect.
 

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I've found that this engine is very susceptible to small variable changes. A slight head wind and it'll drop a few mpg. 5 mph faster and it'll drop a few mpg. Going up in elevation (even a very slight grade) and it'll drop a few mpg. "Bad" gas could be a contributor too. I usually try and get the same brand gas all the time, partly because I'm OCD and need that sort of consistency and order in my life, but also because I know different brands add or omit different treatments/chemicals (some of which I don't want in my vehicle), so that'll also affect engine efficiency. Not sure how much, but I'm sure it's not zero affect.
I agree about headwind, it does play a huge factor in this truck. My Colorado wasn't as sensitive to headwind. As far as elevation goes, from A to B, the elevation is lower in my case.

I had a CE light when I first got the truck, fuel injector #2 out of parameter. Applied new program per tsb, but wonder if it is indeed a bad fuel injector
 

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I agree about headwind, it does play a huge factor in this truck. My Colorado wasn't as sensitive to headwind. As far as elevation goes, from A to B, the elevation is lower in my case.

I had a CE light when I first got the truck, fuel injector #2 out of parameter. Applied new program per tsb, but wonder if it is indeed a bad fuel injector
Ahh, yeah, if you have previous problems with engine efficiency issues then I guess that would be someplace I would look first as well.
 

chuck stein

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I don't know for sure. I've been told it has to do with the pistons/rings getting a little wear. It could also be the things you mentioned.

I would think this only applies to the "break in" period. I would imagine at some point the engine would get so much wear that MPG would start to decrease.

I'm sure someone with more knowledge will chime in regarding this.
Yeah, you would be right to question that claim. There's no wear in the engine that will account for that change in MPG's.
Would not put it past them to code into the ECU some bogus math, so that over time you feel good about the "increased" MPG's as the vehicle get's more dirty with use. Remember, VW was busted by CARB for messing around with ECU code.
 

chuck stein

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If you never reset the mileage calculator, you're essentially adding more and more data to that calculation. It doesn't necessarily save the data, it just keeps adding the instantaneous mileage to the calculation at the iteration it usually would (every 10 miles or whatever it does). I like to do that with Trip 2 stuff, never reset it and see where it goes, while resetting Trip 1 every fill-up.

The only reason you wouldn't see a relatively small and quick change like that is because it is just that, a small and quick change relative to all the large amount of data already used. It would change the average of course, but only by a minuscule amount. You don't use the lifetime average as a guide for anything.
So, what exactly is the math? Every 10mi it takes a 10mi avg and then avg's that back with the last one? That would be very false math if the number is a "lifetime MPG avg".

As example, lets say every 10mi it takes avg from ten data points (one per mi), and over 140mi it's 20,20,20,20,20,20,20,20,20,20,20,20, avg = 20.
what if it's 20,20,20,20,20,20,20,20,20,20,20,20,10, avg = 15 !! Very FALSE

I suspect Ford is lying when it says "lifetime MPG avg".
 

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So, what exactly is the math? Every 10mi it takes a 10mi avg and then avg's that back with the last one? That would be very false math if the number is a "lifetime MPG avg".

As example, lets say every 10mi it takes avg from ten data points (one per mi), and over 140mi it's 20,20,20,20,20,20,20,20,20,20,20,20, avg = 20.
what if it's 20,20,20,20,20,20,20,20,20,20,20,20,10, avg = 15 !! Very FALSE

I suspect Ford is lying when it says "lifetime MPG avg".
The MPG counters in the CPU aren't at such high intervals. They're time-based not distance based, and I believe it's every 2-5s that the ECU takes the current MPG and adds it into the calculation for MPG.
 

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So, what exactly is the math? Every 10mi it takes a 10mi avg and then avg's that back with the last one? That would be very false math if the number is a "lifetime MPG avg".

As example, lets say every 10mi it takes avg from ten data points (one per mi), and over 140mi it's 20,20,20,20,20,20,20,20,20,20,20,20, avg = 20.
what if it's 20,20,20,20,20,20,20,20,20,20,20,20,10, avg = 15 !! Very FALSE

I suspect Ford is lying when it says "lifetime MPG avg".
Your example is not what I was positing. Obviously that's not how averages work. I don't understand how the computer calculates the mpg. Sounds like @Gizmokid2005 maybe has a better understanding. I'm a structures guy, looks like he's a systems/data guy, so I'd trust him over me in this area. The system may not be perfect, but that doesn't mean we disallow its use completely. Especially if all we're using the lifetime mileage data for is as conversation.
 

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Did my first fill-up. Stock 2019 XL 4x4. Mostly short drives in town, pretty flat terrain and cold weather (Indiana). Computer (re-set as I was leaving the dealership) said 19.9. Hand-calculation yielded 19.0, although this should be taken with a little grain of salt as I don't really know how the dealer fill compares with the fill I did.
 

chuck stein

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The MPG counters in the CPU aren't at such high intervals. They're time-based not distance based, and I believe it's every 2-5s that the ECU takes the current MPG and adds it into the calculation for MPG.
ok, so data points every 5sec. Sec or Mi does not matter, it's still the same problem I noted earlier.
It also does not make sense, because at hwy speed when you throttle down to idle %pwm the MPG's go almost to infinity during every 5sec diff, and as such there's no way to store that # in the ECU unless they truncate it off to say 1024, which means you need 10bit register for the data point and one for the calculated math # called "lifetime mpg". And since 10bit is not accurate the math result will not be accurate.

Then look at stomping the gas, MPG is between 0 and 1. When it's less than one the register needs be bigger than 10bit and will also be truncated when the number is very small less than 1, etc. Idle at a red light, MPG is zero, which makes no sense when doing averages. Lets say you driving hwy for 2hrs and 135mi and you get a solid 22mpg, then come to a light, one 5sec datapoint says "0mpg" bringing your avg down to 11mpg in just 5sec, down to 5.5mpg in just 10sec, etc etc.

So unless the actual math for "lifetime avg" can be shown, it's generally a BS # in context of "lifetime".
 

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ok, so data points every 5sec. Sec or Mi does not matter, it's still the same problem I noted earlier.
It also does not make sense, because at hwy speed when you throttle down to idle %pwm the MPG's go almost to infinity during every 5sec diff, and as such there's no way to store that # in the ECU unless they truncate it off to say 1024, which means you need 10bit register for the data point and one for the calculated math # called "lifetime mpg". And since 10bit is not accurate the math result will not be accurate.

Then look at stomping the gas, MPG is between 0 and 1. When it's less than one the register needs be bigger than 10bit and will also be truncated when the number is very small less than 1, etc. Idle at a red light, MPG is zero, which makes no sense when doing averages. Lets say you driving hwy for 2hrs and 135mi and you get a solid 22mpg, then come to a light, one 5sec datapoint says "0mpg" bringing your avg down to 11mpg in just 5sec, down to 5.5mpg in just 10sec, etc etc.

So unless the actual math for "lifetime avg" can be shown, it's generally a BS # in context of "lifetime".
Yes, seconds or miles matters, a lot. If you're calculating in miles, you don't calculate MPG while you're stopped, which you absolutely do if the engine is running and using fuel, so consumption has to be graphed and stored in runtime *and* distance as a combination, because the same holds true if the engine is coasting down a hill and not burning fuel. This is similar to how you'd calculate power usage of appliances not by their runtime, but by the power draw.

Since I don't have the internals of exactly how the ECU handles it, I can't tell you for sure, but it does capture and use the "infinite" mileage as part of the calculation, if you're moving and not burning fuel, that is *technically* an infinite calculation, the in-dash screen is limited at 99.9, but who knows what it's stored at, my guess is probably the same, my Mustang acted the same way.

I'm not sure where you're caring about the register sizes, modern technology doesn't generally care about the memory registers in nearly the same capacity they used to. The field is likely a float or limited length decimal field. You are at 0MPG when you're stopped and idling (the display reports 0MPG when you're stopped and start/stop has it off as well, but these values are not registered for the calculations), you also generally see 4mpg+ when under full throttle.

Lets say you driving hwy for 2hrs and 135mi and you get a solid 22mpg, then come to a light, one 5sec datapoint says "0mpg" bringing your avg down to 11mpg in just 5sec, down to 5.5mpg in just 10sec, etc etc.
This is where I think you're misunderstanding. This isn't how it works. You're likely looking at 1440 data points (every 5 seconds for 2 hours) at 22mpg, then one datapoint at 0mpg, that 1 out of 1440 data points is not going to bring your average down like that. The vehicle doesn't calculate an average without proper weighting. This can be done in various ways, by storing all 1440 data points, or storing the average and the number of data points in that average (so two values, 22 and 1440) and then calculate the new average by adding one to the data point.

These are quite trivial calculations that the ECU is going to be more than equipped to handle. The specifics on exactly what intervals are used and the exact math are probably "company proprietary" or similar, but the way an average gets calculated is the same. You either store all the values you are averaging across, or an average number and the number of points that gave you that average.

Just to add, this is roughly how the math would work out for those averages:
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