Welcome to ZRoadster.org - BMW Z1 Z4 Z8 Z3 Forum and Technical Database

If you want to join in with the discussion, and see the areas which are available only to members then sign up now!

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Onboard Computer inaccurate MPG

Discussion in 'Z4 Roadster & Coupé' started by dangermouse, Nov 18, 2014.

  1. dangermouse

    dangermouse Regular Member

    Joined:
    Aug 29, 2013
    Messages:
    16
    Likes Received:
    7
    Trophy Points:
    14
    Hi all,

    I believe there is a way to access hidden menus in the OBC to correct inaccurate reading on the average MPG. Unfortunately all the results I have got from Google give a link that is broken. Does anybody know how to do this please?
    My Z4 is lying to me to the tune of 4 or 5 MPG although the mileometer, fuel gauge, miles to empty and speedo are all accurate as far as I can test them
    I could ignore it, but then I can't 'cos once I get a bee in my bonnet..........
     
  2. hard top

    hard top Zorg Expert (I)
    Dutch Zeds The M44 Massive

    Joined:
    Dec 5, 2011
    Messages:
    20,780
    Likes Received:
    6,065
    Trophy Points:
    213
    Location:
    Netherlands
    Sorry, I have not got an OBC in my 96 Z3 and the chap that could probably tell you is away for a week.
    There might be someone else on here though that might know?
     
    • Agree Agree x 1
    • Thank You! Thank You! x 1
  3. t-tony

    t-tony Zorg Expert (I)
    Supporter British Zeds #ZedShed

    Joined:
    Dec 31, 2013
    Messages:
    33,097
    Likes Received:
    15,588
    Trophy Points:
    220
    Location:
    Torksey Lock,Lincoln, England
    Model of Z:
    Z4 3.0 Auto
    Same here, only mines 2000 2.0 Auto without OBC. So sorry no help but at least we're taking notice.

    Tony.
     
    • Thank You! Thank You! x 1
  4. roadvoyager1

    roadvoyager1 Zorg Guru (I)
    British Zeds

    Joined:
    Dec 1, 2013
    Messages:
    676
    Likes Received:
    494
    Trophy Points:
    92
    Location:
    Shotley Bridge
    Model of Z:
    2.8ltr
    • Thank You! Thank You! x 2
    • Like Like x 1
  5. dangermouse

    dangermouse Regular Member

    Joined:
    Aug 29, 2013
    Messages:
    16
    Likes Received:
    7
    Trophy Points:
    14
    Thanks, will do
     
  6. GazHyde

    GazHyde The Gaz Monkey
    Staff Member Administrator Global Moderator British Zeds

    Joined:
    Dec 2, 2011
    Messages:
    15,251
    Likes Received:
    9,504
    Trophy Points:
    226
    Location:
    Newbury, Berkshire
    Model of Z:
    BMW Z4 3.0Si Sport
    My 2003 3.0 Auto had the most accurate OBC on any car I have owned. Was always within 1-2 mpg of what I worked out manually.
     
  7. dangermouse

    dangermouse Regular Member

    Joined:
    Aug 29, 2013
    Messages:
    16
    Likes Received:
    7
    Trophy Points:
    14
    Funny enough this is the first BMW I've had with an inaccurate reading. I suspect it might be due to a change from the original wheels
     
  8. t-tony

    t-tony Zorg Expert (I)
    Supporter British Zeds #ZedShed

    Joined:
    Dec 31, 2013
    Messages:
    33,097
    Likes Received:
    15,588
    Trophy Points:
    220
    Location:
    Torksey Lock,Lincoln, England
    Model of Z:
    Z4 3.0 Auto
    If the rolling circumference of the new wheels and tyres is the same as the original set it shouldnt make a difference. You can find what the car originally had by looking at a thread by GazHyde on this subject.

    Tony.
     
    • Thank You! Thank You! x 1
  9. dangermouse

    dangermouse Regular Member

    Joined:
    Aug 29, 2013
    Messages:
    16
    Likes Received:
    7
    Trophy Points:
    14
    Hi Tony, unfortunately my OBC isn't the same as the E36 and doesn't have the buttons described in the article. Hopefully the info about the different codes will be useful if someone can tell me how to get into them on the Z4