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Trip Computer MPG Inaccuracy

Discussion in 'Audi S4/A4/A4 Cab (B8 Chassis)' started by wolfie138, May 13, 2013.

  1. wolfie138
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    wolfie138 Active Member

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    [May 13, 2013]
    has anyone noticed an issue w/ this? i've been filling up 10 gallons a time for a while to see what mileage i'm getting. at the end of every trip, the trip counter "current mpg" thing is showing mid to high 30s, and yet everytime i'm filling up again at the same point (ie when the low fuel light comes on) and i'm lucky to have cracked 320-some miles, whereas the trip numbers suggest i should be around 350.
    why so much discrepancy?
    #1
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  3. johnnythepie
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    johnnythepie Active Member

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    [May 13, 2013]
    lmao!!! And you are worried about losing 30 miles on a tank? I fill my 2.0tdi up to the brim, dis says i have a range of 600 miles (audi figures suggest 800 on a tank), but i actually get 450 with 5 miles left in the tank.Whilst im driving the dis tells me im doing 36-49 mpg.Whe i fill up to the brim again, i get 32-34mpg.Audi allow for a discrepency of upto 30% on its figures, mine is more like 40%.Whether i boot it or not, urban/motorway or mixture of both.The dis lies.Massively!!!!
    #2
  4. scoTTy
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    scoTTy Active Member

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    [May 13, 2013]
    Mine's bang on :happy:

    but then I did tweak it via VCDS :laugh:
    #3
  5. enoliver
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    enoliver Member

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    [May 14, 2013]
    May I ask, when you fill up, do you reset ALL of the trip readings, ie average consumption, instant consumption, miles to go, miles done? Because, i have found that if you don't, the average will take the average of the continual readings, rather that that particular tank. I have found that when I do all of these, the range reading is higher than I actually get, but the average consumption reading is quite accurate, when I calculate it myself. I have also found that for me the best way to determine the true consumption is to brim the tank, then at any given point, I brim it again, and then calculate how much fuel I have put in and the miles done; obviously, the lower you let the tank get, the more accurate the average will be.
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  6. johnnythepie
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    johnnythepie Active Member

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    [May 14, 2013]
    yup, reset everything for what its worth. Only way to get an accurate reading is a brim job (!) , and use fuelly to track previous readings
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  7. Furkz
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    Furkz Active Member

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    [May 14, 2013]
    its all bull**** tbh, my 2.0 tdi did 450 on its last tank (1st tank since i had it, had revo map halfway through too). now done 160miles and showing 250miles left on DIS. its all urban too where the last tank was mixed and some hard driving testing out the map.

    however i had a 8G Cab that was a 2.8V6 and managed 300miles urban and 330-350 m'way, when i got the diesel i was expecting 600miles+ what a shock i got :tumble:
    #6
  8. 5102 IA
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    5102 IA Member

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    [May 14, 2013]
    I've the 3.0tdi quattro and get 450 from a tank... unless the tank is bigger, something must be wrong here.
    #7
  9. Furkz
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    Furkz Active Member

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    [May 15, 2013]
    you might drive more economically or have the car setup better (tyre pressure, serviced, etc) theres so many factors to take in, but estimated figures are a let down unless you drive in top gear at the right cruising speed and hardly ever brake than you might get close to the figures
    #8
  10. bez101
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    bez101 Yorkshire & Humber Rep. Regional Rep VCDS Map User

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    [May 15, 2013]
    i dont worry about it
    just fill it up drive how i drive an dget what i get
    cant change it
    #9
  11. johnnythepie
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    johnnythepie Active Member

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    [May 15, 2013]
    Fair comment!!! I might just take the advice
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  12. JPM
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    JPM New Member

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    [May 16, 2013]
    I use an Android app called aCar to keep track of my fuel expenses. What I have found is the DIS is wholly inaccurate.

    I get a range of 240 -250 miles from a brimmed tank. Every time I fill up, and reset DIS, the range starts at 320.

    Average DIS MPG on a tank is usually 21 mpg . In reality its between 18-19mpg.

    I also find no matter how I drive I seem to get the same range out of the tank. I tend not to get too hung up on fuel economy. If I did I would never have bought an S4.
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  13. riggssuzuki
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    riggssuzuki Active Member

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    [May 16, 2013]
    If you really want good fuel economy buy one of those 70 mpg ford deisels otherwise dont worry. Personally i never look at the mpg as it doesnt dictate how i drive.
    #12
  14. johnnythepie
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    johnnythepie Active Member

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    [May 16, 2013]
    I think that the point bieng made is the blatant lies both electronically and quoted performance wise.
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  15. 5102 IA
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    5102 IA Member

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    [May 17, 2013]
    ...and that perhaps downsizing might not bring the benefits you'd expect, if you want to travel at the same pace.
    #14
  16. miatang
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    miatang New Member

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    [May 17, 2013]
    They cant even get your speedo to register the correct speed so how can you expect them to give you the right mpg.
    #15
  17. Crazyfool
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    Crazyfool Lead boot

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    [May 19, 2013]
    Agreed.

    This has come up on ASN quite a few times, but at the end of the day Audi calibrate their cars on a rolling road, not on real ones. My father had his checked out and Audi said there is nothing wrong. I measure at least a 12% discrepancy with my Avant. I have however gained almost an extra 4mpg by changing the tyres to energy efficient Goodyears. Almost making 29mpg...woohoo!
    #16
  18. xs2man
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    xs2man Member

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    [Jun 4, 2013]
    I had a run in with Audi when I bought my last A4. Their literature lies like fook on the subject, hence why I sold them the car back less than 3 months later.

    Although, having said that, the DIS was completely accurate when it came out the factory. Of course, because of their tampering with the computer (which they did wrong anyway, thinking that making the DIS read better consumption would help my fuel consumption? I tracked it with fuelly, which was all but bang on with what the computer was telling me), but they rigged it the wrong way so it looked worse.
    #17

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