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REALLY bad MPG

Discussion in 'A3/S3 Forum (8L Chassis)' started by nick4501, Feb 17, 2011.

  1. nick4501
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    nick4501 Member

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    Hi guys. Recently my MPG has seemed to get worse. I put this down to constantly running under full operating temperature (due to a dodgy stat), but after replacing it, it still hasn't improved fuel economy.

    Last week I put £60 worth of v-power in it. I've since done 105 miles and it's just hit the half way mark. Surely a stage 1 A3 should be getting more than 210 miles from a full tank?! I don't really drive like a nutter and never take it above 3k rpm until it's at 90 degrees.

    During my last MOT, I was advised that the "fuel filter looked soggy and smells of fuel". Could this be the cause?

    Suggestions?
    #1
  2. s3dave
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    s3dave TFSI Hybrid

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    Not sure how he looked at the filter as its a sealed metal unit, :think: could do with logging really
    #2
  3. crazychris
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    crazychris Member

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    I agree with Dave get it on vag com check your fuel trims( can't remember hoe you do that) also try reset g the throttle on vagcom aswell, I had this problem and ended up swapping the engine temp sensor as the stat cured it a lil but not alot once that was changed I've been running 31mpg around town and to work etc 34 on long run and I only put tesco unleaded in lmao, changing the filter wont harm anyway as there about a fiver and about a five minute job to..... Have you serviced the car at all recently and what are the plugs like mate?
    #3
  4. SamiG
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    SamiG On Boost, ish.

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    I've got a standard 210 S3. A full tank of vpower at about £83 / 60litres will give me about 300 miles of combined driving (mainly stop start short journeys)

    It can vary from as little as 250 miles to up to about 350 depending on my driving style at the time.

    I wouldn't say your's seemed massively bad though...
    #4
  5. superkarl
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    superkarl MAN OF STEEL

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    i changed my fuel filter when i bought my car, it was soo soo dirty, putting v-power in and other side it was brown! changing it felt so much better!
    #5
  6. S3KO4
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    S3KO4 Member

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    It's a must to change your filter, even more if you have ran her on red lights, a few time i.e. when it shows you have 5mils trip remaining. the pump will suck up all the dirt built ups in the bottom of the tank
    #6
  7. nick4501
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    nick4501 Member

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    The car is regularly serviced, so has no excuse for this kind of MPG. Surely S3's should go through more petrol than an A3?

    Thanks for the advice guys. I guess it's time to replace the fuel filter.
    #7
  8. adzy
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    adzy New Member

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    Mate I had the same problem and still do to a point,

    I have a stage 1 unknown remap on my S3 with a pipercross induction kit an i was getting around 22 - 23 i put some CATACLEAN in my tank once a month for two months and now with that and driving it like a pensioner (unless someone wants to av it of course) i now get between 25- 26 still shit really but it did help! Its about 15 quid a bottle.
    #8
  9. S3KO4
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    S3KO4 Member

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    V-power always gives me around 30mpg average on the dash mix driving, while the 95 ron stays around 24-26 but damn 9p extra is a bit too much, the only other nice thing about the 95 is sometimes is so bad I get bangs and pops while changing gears, tiny flames from un-burned fuel.. :)
    #9
  10. shanejess
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    shanejess Guest

    my missis takes the car 2 work mon-fri, i only drive it at weekends, i think we both need 2 speed up lol i only ever put v-power in the tank and get between 340/360 miles per tank.
    #10
  11. JS1500
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    JS1500 Howdy

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    I'm only getting an absolute max of 280 miles to a tank of V-Power. When the weather was even colder I was getting about 240 miles!
    DIS read 23mpg for ages, now at almost 25mpg after using injector cleaner/slightly warmer weather... but whatever I do I can't get it to stay over 25 for long.

    62L tank isn't it?
    #11
  12. finesse
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    finesse Active Member

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    240 miles, that's insane

    need to check
    MAF
    VAC leaks
    lambda sensors
    tyres
    charcoal cannister
    fuel filter
    #12
  13. voorhees
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    voorhees Moderator Staff Member Moderator

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    Letting your missus drive your car....thats insane !! :)
    #13
  14. JS1500
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    JS1500 Howdy

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    Yeah it's not the best for the wallet!

    MAF was new in October
    Vac leaks checked for 3 weeks ago
    lambda sensors - would this throw a fault code? If so they're fine.
    Tyres - no probs
    Charcoal cannister - how could I tell if this was the problem?
    Fuel filter - Will be changed next month

    Thought I had a problem with the thermo as the car was struggling to reach 90 (on gauge). Now the weather's a bit warmer it reaches 90 but sometimes drops a bit when moving quickly... I was told by my usual (Bosch certified) garage that it was ok?

    I do leave the car to warm up for a couple of minutes when I get in, do fairly short trips and leave to idle before I get out...


    Off topic: I never did find the receipts for the brakes finesse, sorry. I had a good look, but nowt.
    #14
  15. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    I think it's more due to this leaking fuel filter, you are probably pissing it onto the road.

    Mine did the same and despite it's FSH the filter had never been changed.
    #15
  16. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Filter isnt on the service schedule, so its no surprise its original!!

    Your stat is broken, it should never move from 90c.

    Dont leave the car idling, its not good for it.
    #16
  17. s3dave
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    s3dave TFSI Hybrid

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    1.8ts arnt the freindliest of engines to the budget minded drivers, but stick in a boost leak etc it will drink more than george best used too
    #17
  18. mikeyg
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    mikeyg Member

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    Ive been driving mine like an old man at the minute to try and save on the fuel, and on this tank(of which im half way through) , im getting an average of 37.5mpg according to the display. Im only doing just less than 20 miles a day,and thats across Milton Keynes with many roundabouts!

    It did have a full service last month, including fuel filter. As i always change mine every year as they aint expensive.

    Also the fuel economy seems better on this tank than the last, as when it was low i gave it a proper good thrashing before i filled it up!! It hadnt had one for a while,so im guessign that helped.
    #18
  19. Biggied
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    Biggied They called him mellow yellow.

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    My 210 S3 is the exact same mate, like you say it can vary quite a bit depending on how its used.


    Get your filter replaced ASAP before your S3 ends up as a bloody fireball mate, I'm quite surprised @ that only being an advisory as although it may only have been damp @ the time the potential dangers are pretty serious stuff.

    Ewan.
    #19
  20. XFi
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    XFi Member

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    Agreed, I have a dodgy stat and I did 246 miles a few weeks back which cost me about £40 in fuel (taking it to just above 1/3 left) which works out on average as 30 ish.
    #20
  21. nick4501
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    nick4501 Member

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    This is interesting. I cleaned my MAF about 2 weeks ago. It did seem a lot quicker, but soon returned to it's previous state. No codes being thrown, so lambda sensors should be fine. New tyres last month.

    However, I do have lumpy idle. I really have no idea what is causing it. I don't think it's a boost leak because me and Nick (aka Prawn) logged the requested an actual boost, and all seemed fine. The charcoal canister makes a hell of a noise though. It seemed to shock Prawn, so maybe that is to blame...?

    Obviously, replacing the fuel filter isn't going to rectify my dodgy idle, so do you guys think that the lumpy idle is related to the poor MPG?
    #21
  22. Westy
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    Westy Double Dark Side! Diesel & 8P

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    I once cleared a bad idle issue by cleaning the throttle body and the Air Intake Sensor with carb cleaner. Might be worth a go! Also I got rid of idling issues when I bought 4 brand new coil packs. I think the packs I had in were a bit weak so I just replaced all 4.
    #22
  23. Flight 666
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    Flight 666 Member

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    Westle how do you go about cleaning these properly and whereabouts is the Air intake sensor? Thanks in advance "once cleared a bad idle issue by cleaning the throttle body and the Air Intake Sensor with carb cleaner" car is a 2002 S3

    Also how do you disconnect the fuel filter only had a quick look at mine last year been meaning to change it but it looked like some sort of plastic connector thingys that could break if pulled/twisted wrong so didn`t investiagte any further due to cold crappy weather..thanks anyone
    #23
  24. danger S3
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    danger S3 Member

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    maybe a stupid question but where is the fuel filter? is it the charcoal cannister near the screen wash bottle?
    #24
  25. Flight 666
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    Flight 666 Member

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    Drivers side 3/4 way down the car just behind the sill kind of a aluminum coca-cola sized canister well thats near as damn it my description anway...
    #25

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