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

What can cause poor mpg ??

Discussion in 'A3/S3 Forum (8L Chassis)' started by motfree, Nov 28, 2010.

  1. motfree
    Offline

    motfree Member

    Joined:
    Sep 12, 2010
    Messages:
    464
    Likes Received:
    0
    Just wondering what is causing my car to use soooo much fuel even when I'm driving sensible ..
    #1
  2. Wozski
    Offline

    Wozski Member

    Joined:
    Jan 17, 2010
    Messages:
    479
    Likes Received:
    0
    Alot of factors can make it worse - especially this time of year as its bloody freezing lol - also having a heavy foot, but if your driving sensibly im not sure what else to say....
    #2
  3. AudiS3-Turbo
    Offline

    AudiS3-Turbo Member

    Joined:
    Mar 28, 2010
    Messages:
    578
    Likes Received:
    0
    seems poor mpg threads is popular this time of year lol
    #3
  4. LiveWire
    Offline

    LiveWire S3X

    Joined:
    May 27, 2009
    Messages:
    329
    Likes Received:
    0
    Wide tyres :cold:
    #4
  5. motfree
    Offline

    motfree Member

    Joined:
    Sep 12, 2010
    Messages:
    464
    Likes Received:
    0
    Coolant temp ??
    #5
  6. CHRIS555
    Offline

    CHRIS555 DOPE with added OCD

    Joined:
    Jul 4, 2010
    Messages:
    1,941
    Likes Received:
    0
  7. S3KO4
    Offline

    S3KO4 Member

    Joined:
    Aug 15, 2009
    Messages:
    850
    Likes Received:
    0
    WEIGHT
    WIDER TYRES
    DECAT
    FAULTY SENSORS, MAF, COOLANTS, COIL PACKS..
    FAULTY, THERMOSTAT
    OVERDUE SERVICE
    AIR-CON

    HEAVEY FOOT
    SHORT TRIPS
    BOOSTING and HIGH RPM
    #7
  8. motfree
    Offline

    motfree Member

    Joined:
    Sep 12, 2010
    Messages:
    464
    Likes Received:
    0
    Brand new Maf on 2 weeks ago ..
    Maybe but it's using around £10 for 30 miles and that's not putting my foot down .. Think I'll go to a garage :) as I don't have a clue
    #8
  9. S3KO4
    Offline

    S3KO4 Member

    Joined:
    Aug 15, 2009
    Messages:
    850
    Likes Received:
    0
    I get the same, regardless of how carefull I am.

    Just to add to the list. feel free to add your thoughts

    WEIGHT
    WIDER TYRES
    DECAT
    WORN CLUTCH causing slips. not power no go.
    FAULTY SENSORS, MAF, COOLANTS, COIL PACKS..
    FAULTY, THERMOSTAT
    OVERDUE SERVICE
    AIR-CON
    SEIZING BRAKES.
    WORN OUT BEARINGS


    HEAVEY FOOT
    SHORT TRIPS
    BOOSTING and HIGH RPM

    #9
  10. motfree
    Offline

    motfree Member

    Joined:
    Sep 12, 2010
    Messages:
    464
    Likes Received:
    0
    Actually my coolant sign keeps coming up on my dash ? Maybe that sensor is bust .. But why would this make it use more fuel :-S ??
    #10
    m4tty likes this.
  11. Andrew@A.L.D
    Offline

    Andrew@A.L.D Cylinder Head Master

    Joined:
    Jun 19, 2009
    Messages:
    3,504
    Likes Received:
    3
    Blowing exhaust before the O2 sensor leaking more air in with the ECU thinking the engine needs more fuel

    Boost leak and vacuum leak is also the same
    #11
  12. djarchive
    Offline

    djarchive Member

    Joined:
    Apr 28, 2009
    Messages:
    246
    Likes Received:
    0

    Im getting this only on very cold morning starts though. Anybody know what this is caused by?


    Strange :S
    #12
  13. Imteyaz
    Offline

    Imteyaz 6th Gear

    Joined:
    Oct 2, 2008
    Messages:
    530
    Likes Received:
    0
    It may be fuelling high as the coolant sensor is telling the ECU that the engine is 'cold' and as a result it is pumping a richer mixture through. I would try changing the sensor first, whilst you are at it, check your tyre pressures and also check the state of the airfilter (infact, check when it was last serviced and when it is next due for servicing).

    EDIT: Coolant sign on the dash also comes up when the expansion tank sender decides that it wants to play up - a new one is about a tenner and should sort it out, oh and its nice and white, and not a light brown colour as they tend to discolour over time so it's easier to make a visual check of how much coolant you have in there.
    Last edited: Nov 29, 2010
    #13
  14. s3dave
    Offline

    s3dave TFSI Hybrid

    Joined:
    Nov 11, 2009
    Messages:
    10,120
    Likes Received:
    11
    I got this this morning, just scraping snow of the windscreen and the dreaded 3 beeps showing coolant low, went off within 5 seconds....
    #14
  15. Hector8
    Offline

    Hector8 Member

    Joined:
    Aug 16, 2007
    Messages:
    54
    Likes Received:
    0
    Try the simple things first like wheel allignments and tyre pressures all correct.
    #15
  16. Silverfish
    Offline

    Silverfish New Member

    Joined:
    Jun 26, 2010
    Messages:
    10
    Likes Received:
    0
    Tracking to cure poor fuel consumption Classic fella ,also check parcel shelf straps ,could be that too
    #16
  17. Broken Byzan
    Online

    Broken Byzan Photographic Moderator Staff Member Moderator

    Joined:
    Apr 26, 2004
    Messages:
    12,568
    Likes Received:
    9

    Mr fish, Hector is correct, wheel alignment can cause tyre scrubbing which needs to be overcome by engine power, using more fuel
    #17
  18. Silverfish
    Offline

    Silverfish New Member

    Joined:
    Jun 26, 2010
    Messages:
    10
    Likes Received:
    0
    If you say so ,go get tracking done then and see you in a week when you still have the same problem.
    #18
  19. bengal
    Offline

    bengal Member

    Joined:
    Sep 25, 2010
    Messages:
    537
    Likes Received:
    0
    Tracking can cause higher fuel consumption but i think it would have to be way out though as said by bryzan the engine will be working harder to overcome the resistance caused by this its the same principle as binding brakes and low tire pressures.
    #19
  20. Silverfish
    Offline

    Silverfish New Member

    Joined:
    Jun 26, 2010
    Messages:
    10
    Likes Received:
    0
    Go get it plugged in ffs
    #20
  21. s3dave
    Offline

    s3dave TFSI Hybrid

    Joined:
    Nov 11, 2009
    Messages:
    10,120
    Likes Received:
    11
    lol
    #21
  22. Broken Byzan
    Online

    Broken Byzan Photographic Moderator Staff Member Moderator

    Joined:
    Apr 26, 2004
    Messages:
    12,568
    Likes Received:
    9
    I do say so as it's fact.....

    It is however unlikey that its changed that much without the driver noticing, but it can be a contributing factor if all else has been checked
    Last edited: Dec 3, 2010
    #22

Share This Page