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Abnormally high fuel consumption

Discussion in 'Problems, Fixes, Tips...' started by Jam, Nov 23, 2017.

  1. Jam

    Jam Copenworld Member

    Joined:
    Oct 26, 2017
    Location:
    greece
    Car(s):
    copen
    Sorry to trouble you again guys, but I need your advice. I have the 1.3 Copen now for about a month (98,000kms) and I recorded on the trip computer a distance of around 200km with 60% of the fuel tank, which translates to a consumption well over 10L/km! Of course, there was some traffic driving involved, but still...

    I should note that the car has just underwent serious service with new air filter, new spark plugs, new oil (max quality), new liquids, new tires etc. I should also note that the muffler has been removed by the previous owner, I don't know if that's a factor. Otherwise, I'm not aware of any moding and the car certainly drives like another Copen I drove last month when I was choosing which one to buy... Meaning that there's not additional acceleration or speed compared to that other Copen to indicate a possible hidden performance modification.

    Possible reasons for the high fuel consumption:
    Need to clean up the fuel injection system?
    Problem with sensors/electronics?

    Feel free to add more explanations, thanks.
     
  2. welz

    welz Copenworld Regular

    Joined:
    Jun 8, 2015
    Location:
    Leverkusen, Germany
    Car(s):
    copen 2003
    I cant look in a glass ball, bad octane number in the gasoline, problems with the oxygen sensor, valve problems. does it smoke from the exhaust? and so on. mine turbo needs also 10 liters and more super plus, but its moding.
     
  3. jez77

    jez77 Copenworld Regular

    Joined:
    Jan 16, 2015
    Location:
    Brisbane Australia
    Car(s):
    2003 Daihatsu Copen
    2000 Toyota RAV4
    You've only had the car a month so it's probably down to enthusiastic driving.
    Another thing to look at is too high oil level or wrong too thick oil.
    Low tyre pressure.
    Bad wheel alignment.
     
  4. Jam

    Jam Copenworld Member

    Joined:
    Oct 26, 2017
    Location:
    greece
    Car(s):
    copen
    Wheels are aligned and tyres have proper pressure, oil is fine, no smoke from the exhaust. I don't know about the oxygen and the valves might have to check that. What I'm mostly worried about is some kind of past tinkering with the car computer that I'm unaware of or something of that sort.

    I'm known for my economical driving and I was pretty dissapointed since I drive the Copen to work everyday and I need it to be near normal consumption figures. Anyway, thanks guys I'll ask my mechanic about these things next time I'm there.
     
  5. jez77

    jez77 Copenworld Regular

    Joined:
    Jan 16, 2015
    Location:
    Brisbane Australia
    Car(s):
    2003 Daihatsu Copen
    2000 Toyota RAV4
    You said you had done 200k on 60% of a tank. Have you actually filled the tank yet?
    Could be as simple as a inaccurate fuel gauge or not filling up all the way last time.
    You need to run through a few tanks before you know the real fuel consumption.
     
  6. Salieri

    Salieri Copenworld Veteran

    Joined:
    Jun 19, 2012
    Location:
    Germany
    Car(s):
    Pearlescent White Copen (1.3 K3-VE)
    Did you measure it accurately?
    I mean like filling it to the top and setting the trip computer to 0, driving the car till its almost empty, fill up again, note how many liters you have put in and then dividing it by the number of kilometers driven x 100. fuel consumption in L/100km
     
  7. BarnsleyRob

    BarnsleyRob Copenworld Veteran

    Joined:
    Feb 2, 2017
    Location:
    South Yorks
    Car(s):
    2009/59 silver Copen 1298 cc (now gone to a new home)
    The Copen tank is pretty small so you really need to check consumption on a full tank to tank basis as @Salieri suggests. My 1.3 litre usually returns around 45mpg, but I’ve had it as low as 41mpg and on a recent trip to the coast managed 50mpg - all measured on a full tank to full tank basis.

    My suggestion would be to always measure mpg rather than km/ltr as it always looks better anyway :)
     
  8. Salieri

    Salieri Copenworld Veteran

    Joined:
    Jun 19, 2012
    Location:
    Germany
    Car(s):
    Pearlescent White Copen (1.3 K3-VE)
    Nu-uh, metric > imperial :D
    And its L/100km not km/L (which does not make any sense to me)
     
  9. welz

    welz Copenworld Regular

    Joined:
    Jun 8, 2015
    Location:
    Leverkusen, Germany
    Car(s):
    copen 2003
  10. BarnsleyRob

    BarnsleyRob Copenworld Veteran

    Joined:
    Feb 2, 2017
    Location:
    South Yorks
    Car(s):
    2009/59 silver Copen 1298 cc (now gone to a new home)
    I’m old enough to remember when we bought petrol by the gallon. I’m just wondering if post Brexit we’ll go back to that. Mind you it was £1 a gallon vs around £6 now.
     
  11. Number6

    Number6 Copenworld Veteran

    Joined:
    Apr 25, 2013
    Location:
    Dublin
    Car(s):
    2005 0.7L Copen

    My Copen gets forty rods to the hogshead, and that's the way I likes it
     
  12. Jam

    Jam Copenworld Member

    Joined:
    Oct 26, 2017
    Location:
    greece
    Car(s):
    copen
    Yeah you guys are right, I need to measure with a full tank. My number above was an approximation. But it just feels wrong and I've driven the car on the interstate for 250km back a few weeks ago and I took another measurement with the same result...

    As far as I'm concerned there are two drawbacks with my Copen: One is its sensitivity to bumps (general issue) and the other is the fuel consumption (specific car's issue). If I can solve this fuel thing I will be very happy with it.
     
  13. Vin Petrol

    Vin Petrol Copenworld Regular

    Joined:
    Jan 21, 2017
    Location:
    Stockport
    Car(s):
    2004 0.7 Copen
    What fuel are you using?
     
  14. Jam

    Jam Copenworld Member

    Joined:
    Oct 26, 2017
    Location:
    greece
    Car(s):
    copen
    Unleaded 95 like in my previous car.
     
  15. BarnsleyRob

    BarnsleyRob Copenworld Veteran

    Joined:
    Feb 2, 2017
    Location:
    South Yorks
    Car(s):
    2009/59 silver Copen 1298 cc (now gone to a new home)
    Just over 47mpg on my last tank of standard 95 octane.
     
  16. Cyman45

    Cyman45 Copenworld Newbie

    Joined:
    Mar 7, 2017
    Location:
    Anglesey
    Car(s):
    Copen 659cc
    i know for a fact my fuel sensor is faulty, i get around 240 miles before my fuel level shows almost as empty yet it only takes 30 litres to fill. that works out at around 43 mpg.
     
  17. jez77

    jez77 Copenworld Regular

    Joined:
    Jan 16, 2015
    Location:
    Brisbane Australia
    Car(s):
    2003 Daihatsu Copen
    2000 Toyota RAV4
    Mine normally takes about 30ltrs when showing empty.
    Suppose to be a 40lt tank.
     
  18. Vin Petrol

    Vin Petrol Copenworld Regular

    Joined:
    Jan 21, 2017
    Location:
    Stockport
    Car(s):
    2004 0.7 Copen
    Hmm...thinking about that, I'm sure my Mercedes A class actually showed a reserve after empty, quick search tells me this is common to have and is usually 10-15% of the capacity so 4 to 6 liters is probably left when we're showing empty.

    gallery-1473704534-isthetankreallyemptytho.jpg


    Maybe track it from the halfway point of the tank and see how many liters it takes from there so the reserve is taken out of the equation?
     
  19. Jam

    Jam Copenworld Member

    Joined:
    Oct 26, 2017
    Location:
    greece
    Car(s):
    copen
    Well, I filled it yesterday and started a new trip calculation so I'll have a more precise measurement by the time it empties....
     
  20. Jam

    Jam Copenworld Member

    Joined:
    Oct 26, 2017
    Location:
    greece
    Car(s):
    copen
    After a visit to a good mechanic with 20 years of experience in Daihatsu, the problem has been revealed: High consumption is because of a tampered fuel regulator. Will fix soon:)
     
    Vin Petrol likes this.

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