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2010 Forester 2.5X Sport
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8 Posts
Discussion Starter · #1 ·
Hi all,
I got a 2010 Forester 2.5X Sport. I joined to discuss one of my problem. While I accelerate I see instant fuel consuption as 50L/100 km for a second or 2 seconds, then it drops to 26 L/100km then between 7-12L/100km. This seems weird to to me. The worse is fuel consumption increase from 2L/100km to 24L/100km just before I stop.

Do you know why this is happening? if it’s a problem, how can I solve it?
 

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2010 X Limited, 2.5L NA, 4AT. Purchased as the second owner in 2020 with ~126K miles.
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525 Posts
So what are you reading to get those numbers? It looks like you are reading calculated values base on data points being collected in short term.

When you let off the throttle, it's likely you will go to or near zero consumption.
If you jump on it, you'll go to max.
 

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2010 Forester 2.5X Sport
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8 Posts
Discussion Starter · #4 ·
So what are you reading to get those numbers? It looks like you are reading calculated values base on data points being collected in short term.

When you let off the throttle, it's likely you will go to or near zero consumption.
If you jump on it, you'll go to max.
I‘m reading the values from the display unit. I thought it was a problem beacuse I’ve had Hyundai and Citroen and never saw such values before.
 

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2012 Forester X Auto
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2,662 Posts
I'd be concerned if your actual gas mileage was very poor.
Is it?
What kind of mileage do you actually get - As opposed to the "infotainment" system display?
 

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2010 Forester 2.5X Sport
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8 Posts
Discussion Starter · #6 ·
I'd be concerned if your actual gas mileage was very poor.
Is it?
What kind of mileage do you actually get - As opposed to the "infotainment" system display?
I just purchased the car 3 days ago. I‘ll keep track of the actuazgas milage and then update here...
 

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2017 Forester XT Touring
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710 Posts
"Instant" mileage numbers are always deceiving. Any change in throttle position will change them, because they are estimating the mileage you are getting with the engine in that "instant". Unless you are going to keep accelerating like that for the entire drive, without ever slowing or stopping, it's nothing to worry about.

Change the gauge to show the average reading instead, and you'll be much happier. (Although those gauges tend to be optimistic.)
 

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2017 Foz 2.5i CVT
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2,247 Posts
Accelerating or driving a vehicle at full throttle uses a bunch of fuel. If you fly an F-15 fighter jet at full throttle, it can consume all of its fuel in 6 minutes, using 385 gallons per minute. At full throttle, a Bugatti Veyron will use all of its fuel in 11 minutes. Pretend there is an egg between your foot and the gas pedal to minimize fuel consumption.
 

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2010 Forester 2.5X Sport
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8 Posts
Discussion Starter · #9 ·
Thanks a lot everybody, I‘m relieved now. I was worried because as I said I have never seen these values while driving Hyundai and Citroen.
 

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2011 Subaru Forester
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1,610 Posts
eyup, I checked mine yesterday and you are right the mpg goes up when stopping. Its perfectly normal.
Anyhow thanks for reviving this old thread because within it was something I did not know. That is, if you switch the odometer to the trip meter, then that display changes to avg fuel consumption, and it no longer flips around with every touch or not of the throttle. I am getting 11.8 L per 100 km for pretty much all city driving. I really need to develop a lighter foot when accelerating from a stop sign...
 

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2017 Foz 2.5i CVT
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2,247 Posts
This is an aside, but I filled our '17 Foz at a local station that is 5 miles away from home. 35 mph limit and 2 traffic lights that were both green yesterday. I reset the trip odo when I filled up, and was able to see average mpg bouncing between 56.8 and 57.6 mpg for that 5 miles once it started reading. (Usual average is about 30 mpg for a full tank and I have reached 50 mpg on this same stretch before.)

I had a tailwind yesterday--this is the highest reading I've ever seen out of our Foresters. The 50+ mpg figures are not realistic but are a fun example of hypermiling with a CVT. In my '09 Foz, I could crack 40 mpg by lugging the engine in 5th gear along this stretch.
 

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2011 Subaru Forester
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1,610 Posts
A tailwind? It sounds like you had a sail helping you along. 57.6 mpg in a Forester is mind blowing. That is pretty much 4 L per 100 KM. I think mine might do that coasting down a long hill lol.
 

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2017 Foz 2.5i CVT
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2,247 Posts
No sail except for the tall rear end of the Foz :)

I've been able to get over 40 mpg in my Nissan Murano and Dodge Grand Caravan on the same stretch. Kind of a hypermiling game I play. If I hit a traffic light I lose 10 mpg.

It's not a downhill but it's Lakeshore Road along Lake St Clair so the northeast winds coming over the lake do give a direct push. (I'm also a bicyclist who has been riding this road for over 50 years and know how the north wind can feel on a close and personal basis...)

By the way, I can see Canada across the lake (about 4 miles from my house) and the grow lights for the weed farms in Kingsville are on in the evenings again as days get shorter. But I don't think this would affect the gas mileage display on my dash although the lights were on last night when I saw 57 mpg.
 

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2010 Forester 2.5X Sport
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8 Posts
Discussion Starter · #14 ·
Final note: As @Quadriara 10 mentioned, I change the trip and started to see the average value which is around 10.5 after driving 300km. I think everything was normal!
 
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