Gas Mileage Verification Video
 

OK, as promised to some on here, I have uploaded a video showing how I manually calculated gas mileage and verified the computer generated gas MPG is actually close to manual measurements.

I also show the GPS provided by the new radio I had installed for those interested (radio was $208 delivered on e-bay).

I know, the video quality is kind of crappy and I could have done a much better job, but this is my first try.

If I do it again the quality will be much better. The broken parts at the end of the video are not from my truck.



My gas mileage verification process is as follows:

(1) Fill up tank;
(2) Reset tripometer;
(3) Reset computer generated average MPG reading;
(4) Drive in whatever conditions one wants (city, highway, no load, etc.);
(5) Eventually fill up tank and note the gallons used;
(6) Note tripometer reading (miles driven) and calculate the average MPG;
(7) Note the computer generated average MPG; and
(8) Compare the calculated average MPG with computer generated average MPG.

Bellow are my Mileage testing notes

MILEAGE

I have noted in the past:

City MPG: 17-19 mpg
Highway MPG: 19-21 mpg (70 mph / mostly flat but some hills, no load)

Last time I check mileage after 1 hour highway almost 100% interstate drive : 23 MPG

(I merged on interstate, achieved cursing speed of 70 mph and then put on cruse control and reset computer mileage reading - after 1 hour the computer indicated 23 mpg).


VERIFYING COMPUTER MILEAGE SENSOR

First check: "CITY MILEAGE"

LOTS of idle time (at least 1 hour while radio was installed in truck and 10 degree weather)

NO LOAD
Miles: 58.1
Gallons: 4.7
Measured Mileage : 12.4
Lie-o-Meter Mileage : 11.8
Percent Error: 4.5%


Second Check: Mixture
(20% city, 40% country with some stop signs, 40% interstate)

NO LOAD
Miles: 40.7
Gallons: 2.1
Measured Mileage : 19.4
Lie-o-Meter Mileage : 19.6
Percent Error: 1.1%

The "Lie-o-Meter" seems accurate for the limited measurements above.
(Note: full tank of gas in all test - of course - thus, if the Lie-0-Meter becomes more inaccurate as the tank empties my testing would not detect such problem)


MODS

Below is a list of the MODS I had performed on my truck when the head gaskets failed. Uncharacteristically lucky for me, I found an excellent 6.0 mechanic that also owns a 6.0 and tries to tweak out every ounce of performance for his truck via mods and tunes and he set me up right.

Not sure any one mod is responsible for the MPG performance.

Engine Repair Date: October 18, 2013
Repair Miles : 67,878 miles
Current Miles : 72,500 miles

01. Machined heads - Heads Milled: 12/1000 (0.012) and 14/1000 (0.014) -- No valve work done - just milled heads;
02. OEM head gasket;
03. New OEM push rods (0.050" shorter than original);
04. New ARP head studs;
05. EGR Delete;
06. Replaced oil cooler;
07. Replaced HPOP STC fitting and dummy plugs;
08. Installed 4" MRRP Full Exhaust (removed the "save the world" catastrophic converter [I know, it is catalytic converter but I like catastrophic] );
09. SCT LiveWire TS with EGT probe at manifold;
10. Flushed and replaced coolant and replaced all fluids; and
11. New batteries.

How are you verifying the tank is being filled to same spot each time?

Josh

That is a variable that is difficult to compensate for, and such error becomes far more significant when the gallons used is small (like in my test).

I simply filled the tank at the slowest flow rate that I could clip the handle in the on position. When it clicked off I very slowly continued to fill the tank with the handle half way out until it clicked again.

That is it. But good point, one really needs to empty the tank as far as possible before taking a measurement - such will minimize the refill error.

Always using the same pump? Different pumps and handle click off at different points

Josh

First test: "City" Mileage: Same pump. 4.5% difference between measured and computer MPG.

(now for this test, a small part of the time the truck was idling quite a bit while radio shop installed radio in 5-10 degree weather and blew 3 20 amp fuses and 1 10 amp fuse almost crippling the truck. Not sure if this affected the computer reading]

Second test: "Mixed" Mileage: Different pumps : 1% difference between measured and computer MPG.

[fuses replaced and truck running perfect before this test]


I may do the test one more time and endeavor to minimize the sources of error and find a better way to video.

What I could do is fill the tank until I can see the fuel level and drive until tank is almost empty.

Fill it to the neck. Harpoon the tank and it fills up with only about a gallon to trickle in. Before I cut into my tank, it consistently took 27 gallons at the fuel light and could hold up to 33, that's a lot of variation that pumps with different flow rates can mess with. Now it runs up to 31-32 and I trickle in a gallon and it's done.

Well, I cannot say for sure I could see the fuel line in the tank (just to not remember) but I could definitely see the fuel bubbles and, after the first click off I let the fuel settle for about 30 seconds before the slow manual fill portion and I used a very slow flow rate that took forever until the second click. So I am pretty sure I was close to the same fill level.

I have been driving for a long time and this is only my second vehicle with computer mileage indicator. So I manually calculated mileage countless times over a span of many years and I believe I have the process down. That said, to remove all doubt, I should fill up until I can see the fuel level and almost drain the tank completely before refilling.

A what size are your tires? And what is your gear ratio? I know my tires are larger resulting in less mileage on the odo per mile. I believe this can be achieved and im happy for you. My truck was in the 17-19 mixed and 19-22 range before tires and a few things I added.

Well, I was just posting the gas mileage video to backup what I told another reader on this site. I know many do not believe these trucks cannot get over 20-mpg so I posted evidence of what I claimed is true to the best of my knowledge.

I do not know the gear ratio - stock as far as I know.

Below are pictures of the truck.

it is a 2006 F250

Ford Truck Enthusiasts Forums - Monty Simmons's Album: 2006 F250 6.0 Diesel 4wD Super Duty

Just an FYI: Verified gas millage again using a 3/4 tank of fuel according to fuel gauge.

Conditions: 10% City, 90% Interstate (I40), no load, 65mph to 75mph.

Computer Generated MPG: 21.6mpg
Measured: 452.3 miles / 21.7 gallons 20.8mpg

Difference: 3.7%

OK, I'm impressed with your mileage (and a little jealous,lol) since I'm getting about half that right now with the winter fuel and very cold temps we've been in for the better part of the winter. I have a question about your lieometer on the truck......have you done something to it to make it change so quick? I have an 07 and it takes forever to change even tenths, I mean some times I have to drive fifty miles. I am getting about 12 mpg right now but in the warmer weather I was getting 16.5 mpg but it takes forever to get the lieometer to register a change. right now its in the 0* to 30* range and 12mpg but if I waited to drive it after it warmed up to say 70* it would take a couple of days driving to get it back up to the 16mpg area.

The "lieometer" is an average reading. The "lieometer" is almost a real time meter just after reset. The longer one drives without reset the more data it takes to change the average value.

Basically, a minute of "real time" data has little effect on days of average data.

In the table of average values below, note the following:

Reading 12 "average mpg" is 22.5 mpg
Reading 13 "real time" reading is 6.0 mpg causing the 22.5 mpg average to drop 1.5 to 21.2 mpg average.


Now note

Reading 26 "average mpg" reading is also 22.5 mpg
Reading 27 "real time" reading is also 6.0 mpg, however the average value only drops 0.6 mpg to 21.9 mpg average.

The average value for reading 26 is much more "stable" than the average value for reading 13.

The average value for reading 100 will be much more "stable" than the average value for reading 26 (etc.)


reading real time average
1 33 33.0
2 24 28.5
3 21 26.0
4 23 25.3
5 21 24.4
6 20 23.7
7 19 23.0
8 18 22.4
9 20 22.1
10 21 22.0
11 22 22.0
12 28 22.5
13 6 21.2
14 6 20.1
15 6 19.2
16 6 18.4
17 20 18.5
18 20 18.6
19 20 18.6
20 20 18.7
21 20 18.8
22 21 18.9
23 23 19.0
24 25 19.3
25 23 19.4
26 99 22.5
27 6 21.9
28 6 21.3
29 6 20.8
30 6 20.3
31 6 19.8
32 20 19.8
33 20 19.8
34 20 19.9
35 20 19.9
36 20 19.9
37 21 19.9
38 23 20.0
39 25 20.1
40 23 20.2
41 99 22.1


I used Excel to repeat the above column to 281 vaues

265 23 25.0
266 99 25.3
267 6 25.2
268 6 25.2
269 6 25.1
270 6 25.0
271 6 24.9
272 20 24.9

Note how a real time "6" mpg reading has almost no affect on the average mpg value.

Also, note that I am trying to get the best gas mileage.

I accelerate very slow and coast as much as possible. If I drove like that all the time I would probably piss a lot of people off and get the finger a lot.

"Horn broken - watch for hand signals" kind of thing.

Lol, I've owned this truck since July and did NOT know I could reset the lieometer!!!:-X19 Don't ask me why, I just never thought to push the reset button lol. I guess we really can learn something new everyday. Now if I can just get mine to read 23 mpg I'll be a happy camper.:D

I'd say you are not getting true accurate amounts during fill up. You need to see the fuel at the mouth of the refuel line. This would be your reference that you have filled to the same point during each fill-up. I don't want to burst your "MPG" bubble but the results may not be to your liking. Side note: When filling up in this manner be sure to drive more than 50 miles.. Since fuel will expand the amount in the tank after you leave the pump could cause issues. It's best done when traveling HWY miles for extended periods. I have done this for my regular fill-ups but I make sure to burn off at least 2-3 gallons during my travels if I can.