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New CLS owner-Questions

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by twojags, Dec 31, 2012.

  1. twojags

    twojags Member

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    Joined:
    Dec 30, 2012
    Location:
    Northumberland
    Your Mercedes:
    CLS 2008 320 CDi
    Hello, I bought a CLS 320 CDi year 2008 back in April this year 2012. It is blue with grey interior, it had 36k miles on it at the time, 41k now. Have had two minor problems in that time, one was an engine management light showing-proved to be an exhaust sensor problem, resolved under g/tee. Then last month the off side low beam started to flash intermittently then went out. I have covered how it was fixed in another post. So really all good up to now apart from the fuel consumption, which is the reason for this post. No matter what I do my average fuel consumption seems to be 32 mpg. I live rurally but most journeys are 30 or 60 miles return on reasonably flat roads. On the higher mileage trips ie the A1 to Newcastle its all flat. Tried with cruise control and without, tried in cruise mode and sport mode, not tried using the semi manual gearbox option yet, its an auto so I believe it should be used as such.
    As a former Jaguar lover ( S type with gas conversion now scrapped after crash and currently an XJS 1996 with 42k on the clock ) I am getting used to to the CLS and am quite pleased with it apart from the fuel consumption. Was toying with the idea to get it remapped for economy can get it done for around £300 but that would take a while to recoup in diesel???
    Any thoughts on economy driving of the CLS?
    Have a happy new year everyone. :)
     
  2. pcman_jh

    pcman_jh Senior Member

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    Joined:
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    Location:
    Haddington
    Your Mercedes:
    2013 E220 Cabriolet
    I too bought a CLS320 (09 plate) in Sept this year, but with 94k on the clock.

    I'm averaging 37 MPG - can get 34 ish with town driving, or up to 45 on a run with all dual carriageway - although I have been told I drive like a Vicar!!

    Does your car get to proper temperature on the temp gauge - mines is rock steady at just over half the dial ( can't remember what figure this is). I believe this can make a big difference.
     
  3. OP
    twojags

    twojags Member

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    Your Mercedes:
    CLS 2008 320 CDi
    Thanks for the quick reply pcman, I've tried driving like the pope but makes no difference what style of driving I use same result. Temp is as yours so dont think its a problem. Had thought of getting a remap for fuel economy, retired now so don't do a lot of mileage per year. Had had hoped to get around 40mpg on average and would have been happy with that. Use Asda diesel but that should not make that much of a difference......should it???
     
  4. Gkinghorn

    Gkinghorn Senior Member

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    Location:
    Bournemouth
    Your Mercedes:
    E350 CDI Cabriolet - 2011
    The only figures I tend to believe are ones achieved on Motorway . Town and urban driving figures are just too subjective in terms of where you go , traffic lights etc ...

    Go for 120+ mile drive on thE motorway and see what you get if you keep steady speeds...
     
  5. tode

    tode Senior Member

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    Location:
    NW FRANCE
    Your Mercedes:
    S350 btec 2011
    When you say 32 mpg do you mean computer read-out, or real pump fill-up mpg ?
     
  6. television

    television Always remembered RIP

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    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    I asked him this elsewhere , and he said he just fills up ½ empty tanks, so no not been tried on a tank to tank basis
     
  7. Devonian

    Devonian Senior Member

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    I can't understand how anyone can try to accurately gauge their fuel consumption without filling the tank right up.
     
  8. OP
    twojags

    twojags Member

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    Your Mercedes:
    CLS 2008 320 CDi
    Its quite easy, fill the tank up and reset the trip computer, then when its time to refill check the computer readout mine says 32mpg (almost always). Also take receipt from pump and check mileage against fuel used, its not really rocket science. Having driven for over 40 years and had about the same number of cars I do have a bit of experience, but I'm not perfect. If there is a more definitive way I am all ears. :)
    I know the on-board computers are not 100% accurate but do give a good idea of what fuel is being used.
     
  9. OP
    twojags

    twojags Member

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    CLS 2008 320 CDi
    I have not tried filling up from a nearly empty tank as it is subjective as to when the tank is actually empty ( using the computer again ) and the risk of running out of fuel in a diesel is not a one worth taking in my view.
     
  10. tode

    tode Senior Member

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    On my diesel 350 I get between 37 and 39 MPG, with the computer showing about 4 - 5 % better.

    If you're only getting 32, it may be a good idea to check out the obvious things: air filter, fuel filter, tyres . . .

    Depends a lot on your driving style, of course.
     
  11. pcman_jh

    pcman_jh Senior Member

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    Your Mercedes:
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    There's also a flaw with the fill-up calculation method - you're assuming the car's ability to measure its travelled distance is also accurate...ok this is more accurate than the onboard mpg as it removes the computers measurement of fuel flow/used, but still scope for inaccuracy.

    If you want a really accurate measurement, measure something like 10 miles with your Sat Nav and see what your (reset) trip meter says, then use this to factor in any inaccuracies with the trip meter reading she using the fill-up method.
     
  12. cataloyking

    cataloyking Senior Member

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    Your Mercedes:
    glc amg 4matic
    mpg

    if i were you i would try filling up with ie shell bp esso i am sure u will find a difference i dont want to open a can of worms withthis as there has been a few posts a while back on this subject
     
  13. Driver53

    Driver53 Active Member

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    I was getting 42-45 mpg on a decent motorway run with my old E Class CDI 320. I now have a 2006 C Class CDI and the fuel consumption is dreadful. I rarely get close to 40mpg on motorways - more like 34 - 36 mpg. It's so bad that even though i've only had the car 3 months, i'm considering changing it.

    Problem is, with all the diagnostic 'possiblilities', it could cost a small fortune just to identify the problem [if there actually is one !].
     
  14. 142 TPL

    142 TPL Senior Member

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    Your Mercedes:
    W204 C350 CDI Estate SLK 320
    If you want good fuel economy why by a 320 and not a 220. Probably for the performance so just enjoy it and stop worrying about a couple of MPG
     
  15. S.Speed

    S.Speed Senior Member

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    Your Mercedes:
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    The 57 plate E320 I owned was far better on fuel than the OP.
    Long runs I usually got 44 -46mpg
    Going to work and back was typically 32 - 35mpg, but we are talking serious congested rush hour stuff.
     
  16. gilbert121262

    gilbert121262 Senior Member

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    Your Mercedes:
    s350cdiL w221
    Bravo that man. V power diesel for me and drive it like your hair on fire, stops the inlet manifolds clogging up, again!!!
     

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