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

ML270 Poor MPG

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by rjevon, Feb 2, 2010.

Tags:
  1. rjevon

    rjevon Senior Member

    Messages:
    320
    Likes Received:
    1
    Joined:
    Apr 1, 2009
    Location:
    Staffordshire
    Your Mercedes:
    ML 270 CDi 2002
    Hi All,
    New to the site so please let me know if I am doing anything wrong (I am sure you will ;-) )

    Anyway, picked up my ML270 on a 52 plate last week, 73K on the clock and seems to run very well.

    My main concern is MPG, i have managed to do 300 miles to 73 Litres of Diesel .. that works out at approx 18.5 MPG :-(

    I did half and half towing and reasonable runs, caravan - twin axel.

    I was expecting a bit more from this based on the searches I have done on this forum, but 18.5 is way to low for my wallet !!

    Also, what is the setting on the Air filter for ? Mine shows a complete RED semi circle type thing.

    What should I be looking at and can anyone recommend an independent in Staffordshire / Lichfield area ?
     
  2. dieselman

    dieselman Senior Member

    Messages:
    6,017
    Likes Received:
    7
    Joined:
    Feb 10, 2001
    Your Mercedes:
    A diesel
    The red warning means the filter is due for change, mpg may improve after a new one is fitted.
    Is 18.5mpg bad for a large 4x4 towing a large carrotyvan?
     
  3. OP
    rjevon

    rjevon Senior Member

    Messages:
    320
    Likes Received:
    1
    Joined:
    Apr 1, 2009
    Location:
    Staffordshire
    Your Mercedes:
    ML 270 CDi 2002
    Is the red warning indicator automatic, or do you have to reset this when a new filter is installed ?

    I ask because the Independent Dealer in Nuneaton area said it had been serviced prior to collection..

    Thanks for the info, but even with the caravan I would expect early 20's:?:
     
  4. dieselman

    dieselman Senior Member

    Messages:
    6,017
    Likes Received:
    7
    Joined:
    Feb 10, 2001
    Your Mercedes:
    A diesel
    It has a little knob to twist to reset it, but if blocked it will go straight back to showing red.
     
  5. oigle

    oigle Senior Member

    Messages:
    3,081
    Likes Received:
    407
    Joined:
    Mar 15, 2005
    Location:
    Redcliffe, Queensland, Australia
    Your Mercedes:
    Currently 2003 ML270. 2012 Nissan Maxima 250SL.
    My ML270 does approx 25mpg pulling a 1600kg van at around 100kph/60mph and does 32.5mpg without the van on a long run. Suggest yours is not running well. The air filter could easily be the issue there.
     
  6. panason1c

    panason1c Senior Member

    Messages:
    1,927
    Likes Received:
    6
    Joined:
    Apr 19, 2004
    Location:
    Somerset, UK
    Your Mercedes:
    Mercedes ML270CDI, VW Polo 1.9tdi, BMW K1200RS
    When i'm towing our horse trailer with two horses loaded we get approx 20mpg, otherwise, i get between 28 and 30mpg. The red level is indicating a severely restricted air filter and that in itself would result in poor mpg, reset the indicator 'after' you have renewed the air filter. Low tyre pressures make quite a difference to mpg also....
     
  7. OP
    rjevon

    rjevon Senior Member

    Messages:
    320
    Likes Received:
    1
    Joined:
    Apr 1, 2009
    Location:
    Staffordshire
    Your Mercedes:
    ML 270 CDi 2002
    Thank you all for your advice, I will replace the are filter and give it a once over for any possible fuel leaks.

    Does anyone know of a specialist in the Staffordshire area ?
     
  8. Steve@Avantgarde

    Steve@Avantgarde Forum Supporter Authorised Forum Supporter

    Messages:
    6,924
    Likes Received:
    1,126
    Joined:
    Dec 8, 2009
    Location:
    Bristol/Somerset
    Your Mercedes:
    C220CDI AMG Line Premium, SLR McLaren Roadster, SL55 & C32AMG
    I would suggest doing a air and fuel filter replacement and going to a indie with a star machine so he can have a look at the actual values in the engines ECU.

    Could also be possible you have an injector or 2 outside of the hub range. This may cause a increase in fuel economy.
     
  9. wemorgan

    wemorgan Senior Member

    Messages:
    292
    Likes Received:
    0
    Joined:
    Apr 5, 2008
    Your Mercedes:
    R172 SLK 250CDI
    Is Mercland in Nuneaton convenient for you?
    I've been there several times and have been happy with the work.
     
  10. OP
    rjevon

    rjevon Senior Member

    Messages:
    320
    Likes Received:
    1
    Joined:
    Apr 1, 2009
    Location:
    Staffordshire
    Your Mercedes:
    ML 270 CDi 2002
    Still poor mpg ML270 CDi

    Hi all,

    Sorry for the delay in update.

    Went to the Indi in Nuneaton, changed air filter, plugged in to computer thingy and confirmed all was OK.

    Still not getting above 22MPG, it does not seem to matter what type of driving we do, we just get 22MPG.

    I purchased an ML based on other peoples MPG experience, and that was more that 22MPG.

    I need more, please help.
     
  11. rpe2

    rpe2 Senior Member

    Messages:
    2,863
    Likes Received:
    2
    Joined:
    Sep 25, 2006
    Location:
    Silchester
    Your Mercedes:
    His: 2018 E220 d; Hers: 2016 SMAX
    Is it getting hot? Mrs E's C270 was getting 45-50mpg before the cold weather, it is now doing 35mpg. The engine rarely gets above 60c, I have a new thermostat to fit, but the weather keeps thwarting me :(

    Also the heater booster will knoch a few mpg off (but not to the extent that you are seeing).
     
  12. panason1c

    panason1c Senior Member

    Messages:
    1,927
    Likes Received:
    6
    Joined:
    Apr 19, 2004
    Location:
    Somerset, UK
    Your Mercedes:
    Mercedes ML270CDI, VW Polo 1.9tdi, BMW K1200RS
    Is it sluggish on acceleration?.........ML's are known for problems regarding blocked primary cats, might be worth investigating. Mine does a minimum of 28mpg regardless of how its driven.
     
  13. OP
    rjevon

    rjevon Senior Member

    Messages:
    320
    Likes Received:
    1
    Joined:
    Apr 1, 2009
    Location:
    Staffordshire
    Your Mercedes:
    ML 270 CDi 2002
    Well, the car goes really well. I ave no problems hen driving just the MPG.

    The Temp guage only goes over 70ish when in traffic or towing, all other times it is about 60-70 I would say from the gauge.

    The turbo has a little wistle to it, but no lag.

    I am assured from the dealer (Mercland in nuneaton) that it was serviced prior to my collection, although the air filter had not been replaced and was blocked.

    Replacing this did improve from 18.5 MPG to its curent 22 MPG, but still not what I was expecting. From fill up to when the Amber fuel light comes on I have to put in approx 73 Liters (16 Gallon) 350 Miles, so 350 / 16 = 21.8

    I need more, so should I bite the bullet a replace the Fuel filters or do a full filter service on it ?

    How easy is it to replace fuel filters on these, my old W124 was dead easy.

    Regards
    Richard
    Tel: 07966 429364
     
  14. psmart

    psmart Senior Member

    Messages:
    1,653
    Likes Received:
    0
    Joined:
    Feb 7, 2006
    To give you an idea of mpg from ML's:-
    Just driven my ML500 down to Stuttgart, 500miles and averaged 24.5mpg/60mph over this distance (most of the drive it was 80mph plus stops, roadworks etc).
    On the ML270, I used to get 23mpg at 120mph (flat out), min 28mpg normally and upto 39mpg.

    So, you have a problem, and at 73K, could be the MAF and the thermostat, albeit my C220 has a dodgy thermostat and Im getting very high mpg from it at the moment (-76mpg)!

    Go to another Indie and get another opinion, sounds like the current one could be pulling a fast one.
     
  15. Captain_Pug

    Captain_Pug Senior Member

    Messages:
    72
    Likes Received:
    0
    Joined:
    Feb 27, 2008
    Location:
    Cheshire
    Your Mercedes:
    C Class
    You got 39mpg out of a 270:confused:

    What where you doing? turning the engine and free wheeling down every hill!

    Good effort and well done ;)
     
  16. EuroCLK320

    EuroCLK320 Senior Member

    Messages:
    158
    Likes Received:
    0
    Joined:
    Mar 14, 2005
    Location:
    Lincolnshire (near Horncastle)
    Your Mercedes:
    '99 CLK320 Cabriolet and 2002 ML 270CDi
    Just been on a round trip to the Isle of Skye (1100 miles) and i averaged 33mpg in my ML270. I never thrashed it anywhere and was doing a lot of climbing and descending when going through the Highlands. So, pleased with that.
     
  17. oigle

    oigle Senior Member

    Messages:
    3,081
    Likes Received:
    407
    Joined:
    Mar 15, 2005
    Location:
    Redcliffe, Queensland, Australia
    Your Mercedes:
    Currently 2003 ML270. 2012 Nissan Maxima 250SL.
    Temp at 60-70 is far from good. New thermostat required. Even consider partial blanking off airflow to radiator to get it up to at least 80-90.
    Turbo shouldn't whistle normally. Mine does initially when cold but goes away within 5km. That, and the "no lag" you quoted, indicates the mixture is running too rich. Have you noticed any excessive black smoke from the exhaust when accelerating? All non chipped ML's will have noticeable lag off the mark. I guess there are a number of possible reasons for the rich mixture but would look at your air flow meter as the most likely culprit. It is the primary measurement device for air/fuel mixture. The intake air temp sensor has an important part to play too. Others like the O2 sensor are just fine tuning.
     
  18. santefe999

    santefe999 Guest

    ML Poor MPG

    Hmmm. Is that 22mpg whilst towing or 22mpg driving without your caravan? I do not tow anything with my ML but do not get the benefit of decent long runs. I average about 27 or 28 but do tend to use the power. Can't see the point in constantly watching the fuel gauge when driving 2 tons plus of non aerodynamic, automatic, 4 wheel drive solid engineering. Just enjoy the pleasure!
    Santefe999
     
  19. OP
    rjevon

    rjevon Senior Member

    Messages:
    320
    Likes Received:
    1
    Joined:
    Apr 1, 2009
    Location:
    Staffordshire
    Your Mercedes:
    ML 270 CDi 2002
    Its been to Mertrux as well and they gave it a good bill of health..

    So, unless you guys have any further ideas I am going to replace the thermostat and possibly the Air temp sensor if I knew where that was ??

    I would not expect a thermostat to have such a big effect on MPG, but who knows.

    You guys state figures like 28 - 32 MPG, how are you calculating this ? is it via the Trip computer ? as these are never that accurate. My calculations ae on fuel quantities at the pump / the mileage which is the most accurate way of calculating MPG.

    Are fuel filters easy to replace ? and what about air filters, should I use genuine ? Cooper filter in it at the moment.

    Regards
    Richard
    Lichfield, Staffordshire.
    Tel: 07966 429364
     
  20. psmart

    psmart Senior Member

    Messages:
    1,653
    Likes Received:
    0
    Joined:
    Feb 7, 2006
    It is a combined unit, called the MAF, which sits inbetween the airfilter outlet and the turbo inlet. You also have a few other sensors, such as the boost pressure transducer, which if it were to read wrongly, could make the ECU think more charged air than was actual was passing into the inlet manifold, thus over fuelling. The whole system is a closed loop control system and it double checks the Turbo actuation, air mass, air temperature etc, but leaway has been made so that sensors can go out of tolerance by a margin.

    In theory, the car running cold should affect the mpg as the engine is not running within design parameters. My C class proves this is not quite the case, for a 220 on a C, but the ML, it could affect it. I used to run the ML way below -20'c in the winter and no noticeable degradation in economy came to my attention.

    Trip computer..... that will be for the 'well off' owners.... a lot of ML270's didnt have the trip computer, you had to use one of the dipsticks from whitehall to see how much fuel you had left, or do a brim-brim check.

    73K isnt a lot of miles, could your car have been chipped or tampered with? (if you program the ECU to think the injectors inject less than they actually do, or tamper with the rail pressure sensor then you can over inject fuel - ie. run rich, which gives more performance).

    ...I was running outside pushing it and it was 39 metres per pint ;)
    Just pop your bonnet, left hand side, you will see a black ball shape, in front of that is a small unit with 2 pipes going in, disconnect the cable lower down and then drive your ML, fully loaded, for 800 miles. You wont accelerate very quickly, you will top out at 85 max, but stick to around 50-60 and you'll get this mpg if not more!
     
    Last edited: Mar 2, 2010

Share This Page