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Hail mary... help with horrible gas mileage.

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  #1  
Old 06-30-2018
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Hail mary... help with horrible gas mileage.

I still cant figure out why my truck is still getting such horrible fuel mileage. Last tank was 13mpg city. The truck is a 2009 2.3L auto with 64,000 miles and runs perfectly otherwise. It has no CEL, no stored codes etc. It also just passed state emissions test. Within the past 6 months it has had new air filter, new fuel filter, new plugs and wires, cleaned the maf sensor, ALL fluids changed and I do mean ALL, all new brakes, new front wheel bearings, tire pressure checked and is at 36psi, new belt and tensioner. All parts and fluids motorcraft or better. I don't drive aggressive or speed, nothing is dragging like a brake caliper hung up, I don't carry anything in the bed, I've even switched gas stations to see if that was an issue and have run 3 tanks on good shell v power stuff. Still no big improvements. Wtf is left?!?!?!?!
 
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  #2  
Old 06-30-2018
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Download GPS APP and double check odometer

Or find a highway with mile markers to confirm odometer readings

2.3l engine can't use that much gasoline and still run

So either odometer is off

Or gasoline is leaking out, or being taken out


Physics of it:
2.3 LITER engine can pull in maximum of 2.3 liters of air every 2 RPMs(4 stroke engine), thats at Wide Open Throttle(WOT)

Gasoline's air:fuel ratio is 14.7:1, its a weight ratio, so 14.7 pounds of air to 1 pound of gasoline
1 liter of air at sea level weighs 0.0012 kilograms
2.3 liters would be 0.00276 kg or 0.006 pounds of air every 2 RPM at WOT

So at 2,000rpm, every 2rpm is 1,000 x 0.006 = 6 pounds of air pulled in at WOT every Minute(RPM = revolution per minute) at 2,000rpm
Well it wouldn't be at WOT, so lets say 1/2 throttle and say 3.65 pounds of air every minute at 2,000RPM

So every 4 minutes engine pulls in 14.6 pounds of air and needs 1 pound of gasoline

For liquids, "A pints a pound the world around"

So 1 pint of gasoline is needed every 4 minutes
8 pints in a gallon so a gallon of gasoline weights 8 pounds, a little less actually

8lbs x 4min = 32, so 2.3l engine is burning 1 gallon of gasoline every 32minutes at 2,000rpm

If you were driving at 60mph at 2,000rpm then you would be burning 1 gallon every 32 minutes or per 32 miles

or 32mpg

Because of stop and go driving and general conditions, you wouldn't get that of course

But 13mpg..............not even possible, gasoline is going somewhere besides the combustion chambers on the engine
 

Last edited by RonD; 06-30-2018 at 10:36 PM.
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  #3  
Old 06-30-2018
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Checked speedometer vs GPS on my way home this evening. Spot on. Tomorrow I'm gonna crawl under and start looking for leaks in the tank / evap system lines. Other than that all I can come up with is someone is stealing it. But they would have had to have been robbing me for months!
 
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Old 07-01-2018
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Odometer, don't care about speedometer
On newer vehicles speed signals and odometer signals are used separately so speedometer can be correct and odometer not correct and visa versa
That started in 1995 Rangers, separate electric motors that shared common speed signal, either unit could have a specific problem and not effect the other one

Run your fingers on fuel lines and then smell them, there should be 0 gasoline smell anywhere, check closely around fuel filter connections and fuel rail connection on the engine
 
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Old 07-01-2018
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Roger that, I'll make a highway run and verify the odometer.
 
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  #6  
Old 07-02-2018
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Ron you're an effin genious! On an exactly 102 mile round trip down the highway ( based on mile markers ) my odometer is showing 89.8 miles. I expected some inaccuracy but not 12 miles! So there is a huge chunk of bad math in my fuel efficiency calculations. Now the question is, how do I determine my true fuel mileage without the odometer and how do i fix the odometer?
 
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  #7  
Old 07-02-2018
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So about 12% low, and that's just one test, it could vary even more
12% only puts you at about 16mpg

In 2009 the instrument cluster is run by a microprocessor, 2004 and up Rangers

There is a test mode, read here: http://www.carlogic.org/bg/data/Ford...ler%20mode.pdf

There is an odometer code at the end of above PDF
U1123 D123 SCP Invalid or Missing Data for Odometer << U1123 should come up when you read OBD2 codes, if computer or dash knows there is a problem

I would be lying if I said I knew how the odometer works on the digital dashes, older ones had a worm gear, even electric versions, and it did fail, but just not sure how you would go about fixing/correcting the digital versions

You do have stock tire size, right, or very close to stock?
Look on drivers door label, but if speedometer was correct then you do
 

Last edited by RonD; 07-02-2018 at 07:26 PM.
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Old 07-02-2018
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Looked into it a bit more, but not alot of info on digital odometers out there because of the "rollback" issues.

In any case some of the articles I read said the Computer may also have odometer reading separately calculated stored in memory, it was a maybe not a for sure, it was added to confirm suspected "rollback" of dash odometer.
Ford Dealer may be able access that, and also tell you if your instrument cluster needs to be replaced

And just to bring it up, the dash odometer issue could be from tampering, not saying it is just that it could be if you didn't buy this Ranger new
 
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Old 07-02-2018
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I bought the truck from my dad who bought the truck new in 09' so slim chance it was ever tampered with, I was the only one who ever worked on it. Tires are stock size also. I'm not super concerned with it, not something I'd go tearing the dash apart to fix as long as the speedo works correctly (which it does). I'll check for codes when I borrow my buddy's fancy pants scanner again that can read all those deep codes my scanner doesn't pick up. I'm gonna call the dealer tomorrow to make a general inquiry about the issue, check for TSB's and all that but like I said not something I'm gonna drop a bunch of money or effort into just yet.

I found a GPS phone app that tracks mileage so I'm gonna run that for a while to get a proper fuel mileage estimate. I know GPS isn't super accurate since it only measures on a perfectly flat plane but I live in a pretty flat area so it should be alot better than the effed up odometer.
 
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Old 07-03-2018
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Good plan
 
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Old 08-08-2018
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Just wanted to update. Took it to the dealership and they did something with the computer to fix the issue. The explanation I got was while the speedo and odometer both run off the same sensor, the computer calculates them seperately. The part that calculates for the odometer was out of spec and just needed to be re-calibrated. The tech said only ford has access to the odometer software because of fraud. Dunno about any of that but whatever they did it worked. I just did a 800 mile trip and the odometer was spot on with both the highway mile markers and gps. Re-calculated my mileage with the gps, and the fixed odometer and averaged 24mpg now (highway). Thanks a ton Ron.
 

Last edited by Apexkeeper; 08-08-2018 at 12:25 AM.
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  #12  
Old 08-08-2018
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If in fact it was out of spec; makes a guy wonder how it got that way ???
 
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Old 08-08-2018
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Good work

Never knew that about the digital odometers, but it does make sense
In 2004 Rangers got the full digital dash, so it gets most of its display info from the PCM(computer) via a digital link.

And you can no longer just swap instrument cluster, 2004 and up, because of this, each cluster has a unique ID number now and it is "married" to the PCM at the factory, at the same time they setup the PATS system
If you disconnect cluster or swap in a new cluster the engine will not start because of PATS, so same as wrong key
I have read that a Ford Dealer can "remarry" a new cluster to the PCM if needed, but can't change odometer reading in the PCM, only Ford(engineering) can program odometer and then send it out to a Dealer for install
This is to prevent "rollbacks" of miles which was a common issue with Fords over the years, but not sure if the odometer "programming" part is correct.

Changing how the odometer measures miles would be doable thats just Pulse Per Mile(PPM) calculations, same as speedo uses, and would be required for different tire sizes so Ford Dealer would need access to that.

Question:
Did the miles on odometer change after Ford did the programming?
Or did they stay the same and odometer now correctly calculates the miles?
 
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Old 08-08-2018
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The miles on the odometer stayed exactly the same (65,532 I checked that before and after I dropped the truck off).

But now this has me thinking, how could I ever know the true miles on the truck? I have no real idea how long it was "uncalibrated". The fuel issue was what got my attention and that was only for a few months but who knows if it.was instant or progressive problem. Also obviously my truck is long out of warantee but what if it wasnt? Warantee goes by miles and this issue could put a vehicle out of warantee before it actually is. I should note I wasn't charged for the dealer to fix the issue which I never thought twice about until now. I was originally told $135 for diagnostic and they would call back when they found the issue with another estimate for the repair. When they called they said it was fixed and there was no charge for diagnostic or the reprogramming. Maybe they were worried about potential liability issues?
 
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Old 08-08-2018
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Good info thanks

Yes, it probably does have more miles than odometer is currently showing.
But no liability because then people could sue previous owner for running larger tires, lol, which does the same thing, and if Ford knew about the issue which it reads like they did then they would have sent out a TSB to original owner to bring it in so they could INCREASE the miles driven before he sells it...............................wonder why he never brought it in, lol, so Ford would be covered by the TSB notification.

But 3mpg does add up, thats 30 miles per 10gal, 300 per 100gal, 3,000 miles per 1,000 gallons

If you used 10gal a week then 52 weeks = 520 gal so 1,500 miles a year

That's 13,500 miles since 2009, so you should be looking at 79,000 miles on odometer now, so more of a benefit at this time, for you anyway
 

Last edited by RonD; 08-08-2018 at 06:20 PM.
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  #16  
Old 08-09-2018
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Yea this is one of those cases where ignorance is bliss - when you sign over the truck if you trade it in theres sometimes a form or sometimes on the title stating the milleage is to be correct and true to your knowlege. Which you can explain the odometer problem and show the workorder from the dealership stating its fixed now but you had no idea how long it had been off if you want a clear conscious. OR play ignorance and say it is as far as you know which is half truith since you dont know how long its been broken but fixed now.
 
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  #17  
Old 08-09-2018
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Oh dont worry, I dont get rid of vehicles until they turn into dust lol so no worries about future owners.
 
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