Long Term MPG Deceiving

[dlgl00]

I have a 2010 FFH with 23K miles on it. The city/highway mix is probably 25/75%. I keep track of my mileage on a spread sheet from the day we bought the car (I know, get a life). The MPG since we bought the car is 37.5 on paper. For the first 11K miles the long term MPG started about 41 and was slowly working its way down to what my calculated mileage was. It showed about 38.4 on the dash display.

 

At 11K I had the dealer upgrade the program as recommended for some brake anomalie. After that, the LT MPG began creeping up until today it hit 41.1. My calculated MPG since day 1 is 37.5 and the calculated MPG from the point the reprogramming took place is 38.0. It appears that when they did the reprogramming they changed the Long Term MPG algorithm so now it is producing an erroneous MPG calculation.

 

I filled the tank today and the "Miles to E" registered at 701 when I started the car. That would imply they are using the 41.1 number to calculate the Miles to E. This is now a deceiving number. I am not really worried about running out of gas but I was just wondering if others have experienced this problem. I know bringing this up to the dealer will get blank stares and "never heard of anyone else with this problem". Is there any other place to ask this type of questions to real Ford technical experts?

 

Overall we love our FFH and are pleased with the performance. This problem is a nit compared with the good features we enjoy.

 

Gary

[dogo88]

I have a 2010 FFH with 23K miles on it. The city/highway mix is probably 25/75%. I keep track of my mileage on a spread sheet from the day we bought the car (I know, get a life). The MPG since we bought the car is 37.5 on paper. For the first 11K miles the long term MPG started about 41 and was slowly working its way down to what my calculated mileage was. It showed about 38.4 on the dash display.

 

At 11K I had the dealer upgrade the program as recommended for some brake anomalie. After that, the LT MPG began creeping up until today it hit 41.1. My calculated MPG since day 1 is 37.5 and the calculated MPG from the point the reprogramming took place is 38.0. It appears that when they did the reprogramming they changed the Long Term MPG algorithm so now it is producing an erroneous MPG calculation.

 

I filled the tank today and the "Miles to E" registered at 701 when I started the car. That would imply they are using the 41.1 number to calculate the Miles to E. This is now a deceiving number. I am not really worried about running out of gas but I was just wondering if others have experienced this problem. I know bringing this up to the dealer will get blank stares and "never heard of anyone else with this problem". Is there any other place to ask this type of questions to real Ford technical experts?

 

Overall we love our FFH and are pleased with the performance. This problem is a nit compared with the good features we enjoy.

 

Gary

 

Same here. I've got 14k on mine and while I don't do the spreadsheet thing, My driving is probably the opposite of yours. 75/25 - city/highway. I do calculate mileage at every fill-up from miles driven from the last fill-up. I consistently get 37.5. It sometimes dips a bit if I've been a bad boy. When I'm better then it gets up to 38.2.

 

I still get almost double what I got on my 99 LeSabre I traded in and it rides great. So for me it's a winner.

 

Dan

.

Edited September 2, 2010 by dogo88

[lolder]

The "Long Term Economy" is reset in the display menu. The distance to empty DTE is a running average of the last 500 miles. The "Average MPG" is the average since the last reset. The software update didn't change any of that. The higher mileage is due to higher summer temps or improved driving habits. Don't run out of gas, fuel at 1/4 of a tank or more. Pretend you're in a boat or an airplane.

Edited September 2, 2010 by lolder

[Milan_OH]

I suspect your mpg discrepancy is related to your assumption that the LT mpg formula is calculated as you do; (all miles)/(all fuel) since the car was new. While your ledger is an accurate 'Life' mpg, I believe the OBC calculated number is a running average of say, the last 5000 miles for instance, or last 6 months. I'm not sure I've ever seen a published algorithm and not sure FMC wants to publish it because that just invites the anal-retentive crowd (us) to challenge. It's never wise to deal in absolutes when it comes to product specification unless required.

 

That said, I believe it's possible to 'back into' the LT mpg algorithm by resetting the LT mpg periodically and recording all miles and gallons used and analyzing the data......yes, I'm an anal retentive geek too.........

 

Jack in Ohio

[Buster1]

I haven't done any manual calculations, but I also do 75% hwy/24% city and have been getting 38-40 mpg each fillup.

[jerrieric]

My long-term mpg is 43. Right or wrong it makes me feel good. The Avalanche I traded only got 14 but it did carry more cargo. :happy feet:

[jay2000]

Hi,

 

I agree this is decieving. My computer has been telling me I do about 1 mpg better than what my own calculations show.

 

I use a Scanguage II on my other cars and it can be calibrated so that I get a fairly accurate number overall. It seems that my dealer should be able to hook the FFH up to a computer and calibrate it's readout. But, based on my experience, the dealer isn't to comfortable with anything hybrid.

 

And yes, I can mentally subtract 1 mpg from what ever my readout says, but I would have thought the car is capable of this sort of thing.

 

I wonder if the Prius is accurate?

 

Jerry

[lolder]

Hi,

 

I agree this is decieving. My computer has been telling me I do about 1 mpg better than what my own calculations show.

 

I use a Scanguage II on my other cars and it can be calibrated so that I get a fairly accurate number overall. It seems that my dealer should be able to hook the FFH up to a computer and calibrate it's readout. But, based on my experience, the dealer isn't to comfortable with anything hybrid.

 

And yes, I can mentally subtract 1 mpg from what ever my readout says, but I would have thought the car is capable of this sort of thing.

 

I wonder if the Prius is accurate?

 

Jerry

My car reads about 4% high on the mpg put the odometer is 2% low so the net is 2% high on the mpg. Others here have reported very little difference between measured and vehicle computed mpg. The Prius is much worse with 5 - 8% high readings reported.

[akirby]

Hi,

 

I agree this is decieving. My computer has been telling me I do about 1 mpg better than what my own calculations show.

 

I use a Scanguage II on my other cars and it can be calibrated so that I get a fairly accurate number overall. It seems that my dealer should be able to hook the FFH up to a computer and calibrate it's readout. But, based on my experience, the dealer isn't to comfortable with anything hybrid.

 

And yes, I can mentally subtract 1 mpg from what ever my readout says, but I would have thought the car is capable of this sort of thing.

 

I wonder if the Prius is accurate?

 

Jerry

 

You realize that 1 mpg is only a 3% (or less) error? Given the differences in fuel pump measurements and all of the other variables that have to be taken into account by the computer to measure mpg - I'd say 3% is excellent.

[dlgl00]

I appreciate all your comments. I went back and checked the last 500 mi. as was suggested by one of the posts. With that limited range I get an average MPG of 39.9. And if I allow for the 1MPG difference Jerry experiences then I am getting pretty close. I think I will try the reset suggestion just 'cause my engineering background makes me a little AR about these new fangled technical contraptions. Jack is correct in that I was assuming they kept a longer history in order to make the calculations.

 

Thanks again for all the comments

Gary

[akirby]

I appreciate all your comments. I went back and checked the last 500 mi. as was suggested by one of the posts. With that limited range I get an average MPG of 39.9. And if I allow for the 1MPG difference Jerry experiences then I am getting pretty close. I think I will try the reset suggestion just 'cause my engineering background makes me a little AR about these new fangled technical contraptions. Jack is correct in that I was assuming they kept a longer history in order to make the calculations.

 

Thanks again for all the comments

Gary

 

Seriously? You're getting worked up about a 1 mpg difference? Even I'm not that AR. It's just an estimate in the first place.

[rpoffen]

 

At 11K I had the dealer upgrade the program as recommended for some brake anomalie. After that, the LT MPG began creeping up until today it hit 41.1. My calculated MPG since day 1 is 37.5 and the calculated MPG from the point the reprogramming took place is 38.0. It appears that when they did the reprogramming they changed the Long Term MPG algorithm so now it is producing an erroneous MPG calculation.

 

Does anyone know if there is a way to tell if the TSB for the hybrid power train has been applied?

 

When I took mine into the dealer for its first oil change (and the manual seat recliner recall), I specifically asked that they apply this TSB. When I picked up the car, they said that the oil change and the recliner recall was done and it is already to go. I asked about the power train re-program and the guy said "uh, yeah we did that too", kind of like he was unsure what I was talking about. The service order listed the oil change and the seat recall, but no mention of the power train reprogram, so I am unsure if it was done.

 

Thanks

Edited September 9, 2010 by rpoffen

[akirby]

Does anyone know if there is a way to tell if the TSB for the hybrid power train has been applied?

 

When I took mine into the dealer for its first oil change (and the manual seat recliner recall), I specifically asked that they apply this TSB. When I picked up the car, they said that the oil change and the recliner recall was done and it is already to go. I asked about the power train re-program and the guy said "uh, yeah we did that too", kind of like he was unsure what I was talking about. The service order listed the oil change and the seat recall, but no mention of the power train reprogram, so I am unsure if it was done.

 

Thanks

 

Another dealer can check the computer system.

[ctrcbob]

Seeing as how this thread is about MPG, and yes, if and when I get a Hybrid, it will be a Fusion, not a Prius, I want to tell about my best friends Prius out in Roswell NM.

 

Pat picked up his 2009 Generation II Prius in January 2009. (He won it at the "Billy the Kid Casino" in Ruidoso. Twelve months later, when I spent a few weeks with him last December, I got tired of him saying how he was getting xxx mpg. I told him that the figures he was quoting were what he was getting at that very moment, and it was not an average. I asked him how to get the reading for the avg. He did not know. Never went off the screen that shows where the power is coming from. OK, I started to touch various things on his touch screen. The bottom left icon on his screen brought me to the screen that shows the avg mpg since it had last been reset. Car had over 25000 miles on it by then, and he had never reset the mpg. Did not even know it could be done and did not know that there were more screens than the one he always looked at.

 

From January thru December 2009, over 25000 miles, his average was 49.5 mpg. Yes, 49.5 mpg. I was impressed.

 

Does not mean I would buy a Prius, as I like the Fusion better, but 49.5 mpg aint nothing to sneeze at.

[lolder]

Seeing as how this thread is about MPG, and yes, if and when I get a Hybrid, it will be a Fusion, not a Prius, I want to tell about my best friends Prius out in Roswell NM.

 

Pat picked up his 2009 Generation II Prius in January 2009. (He won it at the "Billy the Kid Casino" in Ruidoso. Twelve months later, when I spent a few weeks with him last December, I got tired of him saying how he was getting xxx mpg. I told him that the figures he was quoting were what he was getting at that very moment, and it was not an average. I asked him how to get the reading for the avg. He did not know. Never went off the screen that shows where the power is coming from. OK, I started to touch various things on his touch screen. The bottom left icon on his screen brought me to the screen that shows the avg mpg since it had last been reset. Car had over 25000 miles on it by then, and he had never reset the mpg. Did not even know it could be done and did not know that there were more screens than the one he always looked at.

 

From January thru December 2009, over 25000 miles, his average was 49.5 mpg. Yes, 49.5 mpg. I was impressed.

 

Does not mean I would buy a Prius, as I like the Fusion better, but 49.5 mpg aint nothing to sneeze at.

I know many with Prius's. They all get this mileage no matter how badly they drive. It's about 10 mpg better than our FFH's. There are reports, however, that their car computers are 5 to 8% high. My FFH is only about 2% high and others report less.

[mirak]

I believe the OBC calculated number is a running average of say, the last 5000 miles for instance, or last 6 months.

 

Has Ford ever verified this? That would be disappointing, because I thought I was getting an estimate of the lifetime mpg of the car. I know the only really accurate way to do this is record every fill-up, but I gave that up after a few months because I'm not the only driver. My wife would have mocked me (and rightfully so) if she knew I was logging fill-ups. I was counting on LT to at least give me a pretty good estimate.

 

If Ford is using a rolling average, it must stretch at least 5k miles or 6 months, because my LT says 41 but I'd say I've been doing quite a bit better than that all summer.

[lolder]

Has Ford ever verified this? That would be disappointing, because I thought I was getting an estimate of the lifetime mpg of the car. I know the only really accurate way to do this is record every fill-up, but I gave that up after a few months because I'm not the only driver. My wife would have mocked me (and rightfully so) if she knew I was logging fill-ups. I was counting on LT to at least give me a pretty good estimate.

 

If Ford is using a rolling average, it must stretch at least 5k miles or 6 months, because my LT says 41 but I'd say I've been doing quite a bit better than that all summer.

"Long Term Economy" shown at the bottom of the trip summary after shutdown is the average since it was last reset in the menu. "AVG MPG" is the average since it was reset. Distance to empty (DTE) is a running average of the last 500 miles.

[ICEY]

For the size of the car I feel mileage is great even with the minor descrepencies.

 

What is this manual seat recline recall? Did I miss a post. Certainly I have received no letter from Ford.