Computer Accuracy
Ford Fanatic
Joined: Feb 2016
Posts: 51
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From: Seattle WA
I thought a forum was to share information and results so that people could make informed decisions.
I was told that my truck was performing as it was designed and when I compare my 2012 and my 2015 it is definitely a loss so I want to make sure that people know that.
Did I buy a truck for MPGs no. Was the information that was provided by Ford part of my decision making process yes. Did I expect a lighter weight truck to do worse than a previous model of similar specs? Heck no!
The fact that this truck drank an extra tank of gas in the first 13k miles is of concern to me because that can have several effects other than my pocket book. Were is the gas going? Why doesn't the computer show it correctly? Is my fuel map changing because of the fuel I run? Is there an issue coming up with the engine that I need to watch for?
Being an automotive engineer it was driven into me to keep track of simple things that can be monitored as is can lead you to diagnose a major problem.
Did I say that everyone should run out and go for a class action law suit no. Did VW screw with their computer to make results show what they needed yes. Could Ford being doing the same? Absolutely we have already seen other shady practices by them on other topics.
I was told that my truck was performing as it was designed and when I compare my 2012 and my 2015 it is definitely a loss so I want to make sure that people know that.
Did I buy a truck for MPGs no. Was the information that was provided by Ford part of my decision making process yes. Did I expect a lighter weight truck to do worse than a previous model of similar specs? Heck no!
The fact that this truck drank an extra tank of gas in the first 13k miles is of concern to me because that can have several effects other than my pocket book. Were is the gas going? Why doesn't the computer show it correctly? Is my fuel map changing because of the fuel I run? Is there an issue coming up with the engine that I need to watch for?
Being an automotive engineer it was driven into me to keep track of simple things that can be monitored as is can lead you to diagnose a major problem.
Did I say that everyone should run out and go for a class action law suit no. Did VW screw with their computer to make results show what they needed yes. Could Ford being doing the same? Absolutely we have already seen other shady practices by them on other topics.
You will also find many owners on this forum that are getting, or better then, the advertised EPA MPG on the sticker, hand calculated.
If they wanted to have accurate fuel use measurements, they would need a lot more instrumentation to measure that, making the price of the truck go up. This isn't an aircraft where you need to know precisely the amount of fuel in the tank. Right now, the only thing the truck uses is the float in the tank. Hardly a precise measuring device.
Thread Starter
Senior Member
Joined: Apr 2015
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Originally Posted by i8iridium
If they wanted to have accurate fuel use measurements, they would need a lot more instrumentation to measure that, making the price of the truck go up. This isn't an aircraft where you need to know precisely the amount of fuel in the tank. Right now, the only thing the truck uses is the float in the tank. Hardly a precise measuring device.
The fact that they are off by that much over such a short time is my concern. If the truck was using the float to calculate the mpg I would be shocked!
Last edited by SeatGuru; Feb 21, 2016 at 07:24 PM.
5 Year Member
Joined: Jul 2015
Posts: 5,684
Likes: 1,286
From: SE Michigain
Maybe they are allowing for the injectors to get plugged up. So a new truck uses more than it shows, a 50,000 mile one will be spot on and a 100,000 mile will show more fuel burned than you put in.
Time open X PSI will give you volume through the nozzles only at one nozzle hole size. But if they start off at one size will they stay the same, get dirty and flow less or wear out and flow more?
There are better ways to measure flow but this is probably the cheapest.
Keep in mind most of this fancy stuff we have now is for entertainment purposes only.
Time open X PSI will give you volume through the nozzles only at one nozzle hole size. But if they start off at one size will they stay the same, get dirty and flow less or wear out and flow more?
There are better ways to measure flow but this is probably the cheapest.
Keep in mind most of this fancy stuff we have now is for entertainment purposes only.
Last edited by Livoniabob; Feb 21, 2016 at 10:48 PM.
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Sigh, what does Vdub have to do with anything? We are talking about mileage accuracy not emission standards correct?
Anyway one must remember that within any system there are always tolerance and calibration that must be factored into the consideration of our studies. The gas pumps certainly have a tolerance that must be maintained as well as the tolerance of your particular speedometer.
The US department of transportation deems an accuracy of + or - 10% and specifically + or - 5mph at 50 mph is the tolerance that speedometers must be calibrated to. If your numbers are within the gallonage of one tank of fuel at 13k miles or error rates of 1% and 3% your doing pretty damn good.
Have you also factored for any potential evaporation that may have occurred?
Anyway one must remember that within any system there are always tolerance and calibration that must be factored into the consideration of our studies. The gas pumps certainly have a tolerance that must be maintained as well as the tolerance of your particular speedometer.
The US department of transportation deems an accuracy of + or - 10% and specifically + or - 5mph at 50 mph is the tolerance that speedometers must be calibrated to. If your numbers are within the gallonage of one tank of fuel at 13k miles or error rates of 1% and 3% your doing pretty damn good.
Have you also factored for any potential evaporation that may have occurred?
Well I am starting to wonder if VW did the programming for our trucks...
I am pretty particular about tracking my fill ups and I stumbled across something today when I finally put them into my excel sheet.
I have 13,591.5 miles on the truck so far and kept track of the receipts as I went. So here is the quick math for you guys.
2015 F150 Crew Lariat 3.5L EcoBoost 3.55
Total Miles: 13591.5
Computer Gallons total: 914.3
Pumped Gallons total: 946.056
Difference in Gallons: 31.756 (or in my mind my truck has consumed a full tank of gas that it doesn't know about)
Using Computer MPGs = 14.87 mpg
Using Pumped Gallons MPGs = 14.37 mpg
AKA off by around 1/2 mpg.
Truck averaged 0.42 MPG Worse than the computer showed per fill-up
2012 F150 Crew XLT 3.5L EcoBoost 3.55
Total Miles: 51127.1
Computer Gallons total: 3154.5
Pumped Gallons total: 3190.75
Difference in Gallons: 36.25 (at 13,593.7 off 8.655 gal)
Using Computer MPGs = 16.21 mpg
Using Pumped Gallons MPGs = 16.02 mpg
AKA off by around 1/4 mpg.
Truck averaged 0.08 MPG Worse than the computer showed per fill-up
So 2012 vs 2015
Avg MPG 2015 = 14.37 mpg
Avg MPG 2012 = 16.02 mpg
Computer Error 2015 [(pumped - computer)/pumped] = 3.4%
Computer Error 2012 [(pumped - computer)/pumped] = 1.1%
This sure is raising some questions in my head...
I am pretty particular about tracking my fill ups and I stumbled across something today when I finally put them into my excel sheet.
I have 13,591.5 miles on the truck so far and kept track of the receipts as I went. So here is the quick math for you guys.
2015 F150 Crew Lariat 3.5L EcoBoost 3.55
Total Miles: 13591.5
Computer Gallons total: 914.3
Pumped Gallons total: 946.056
Difference in Gallons: 31.756 (or in my mind my truck has consumed a full tank of gas that it doesn't know about)
Using Computer MPGs = 14.87 mpg
Using Pumped Gallons MPGs = 14.37 mpg
AKA off by around 1/2 mpg.
Truck averaged 0.42 MPG Worse than the computer showed per fill-up
2012 F150 Crew XLT 3.5L EcoBoost 3.55
Total Miles: 51127.1
Computer Gallons total: 3154.5
Pumped Gallons total: 3190.75
Difference in Gallons: 36.25 (at 13,593.7 off 8.655 gal)
Using Computer MPGs = 16.21 mpg
Using Pumped Gallons MPGs = 16.02 mpg
AKA off by around 1/4 mpg.
Truck averaged 0.08 MPG Worse than the computer showed per fill-up
So 2012 vs 2015
Avg MPG 2015 = 14.37 mpg
Avg MPG 2012 = 16.02 mpg
Computer Error 2015 [(pumped - computer)/pumped] = 3.4%
Computer Error 2012 [(pumped - computer)/pumped] = 1.1%
This sure is raising some questions in my head...
Thread Starter
Senior Member
Joined: Apr 2015
Posts: 1,168
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Originally Posted by Livoniabob
My biggest question is why is this 3.5 TT getting only 14.37 mpg.
5 Year Member
Joined: Jul 2015
Posts: 5,684
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From: SE Michigain
And that is my question as well. Some towing of a tiny low profile trailer here and there. My 2012 did so much better. The good news is my dealer checked the truck and it is performing as designed at 17.5 mpg highway.... Yes that is what they said 17.5 Hwy is in spec.