E320 CDI estate...poor MPG?

Discussion in 'General Discussion' started by r11pak, Dec 11, 2008.

  1. r11pak

    r11pak New Member

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    Hi,

    I have just bought a 2001 e320 cdi avantgarde estate.
    The car is great.. goes like a train and drives well for a large car...
    ...however i have not been able to get over 33mpg
    I drove 60 miles at 65 mph and was suprised to see the mpg stay at around 33! My old car was a bmw 325 tds and i used to get 47+
    any advice on this?
    Around town im only getting 16.9 at best...also im driving it carefully..so am worried there is something wrong with it...but there is no diesel leak that obvious!

    lastestly are the front wings ment to have pastic / rubber inserts? mines have nothing!

    thanks a lot

    rupak
     
  2. Diesel Benz

    Diesel Benz Hardcore MB Enthusiast

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    33 miles per imperial gallon isn't bad for an average but if you were driving straight at 65 mph, it should have been able to do better. Since you only did 60 miles, I assume the reading was from the cluster, have you "calibrated" the cluster figures against your book-keeping for fill-ups. Fuel consumption cannot be measured accurately from filling up the tank before and after 60 miles.

    You don't state your mileage, perhaps bad injectors, how about your thermostat, does the engine warm up quickly?

    Comparing with the 3-series BMW isn't exactly fair, less difference on highway but the weight kills mileage at city driving.

    Which inserts do you mean, do you have fog lamps or is it the one in the centre?
     
  3. maddog

    maddog Hardcore MB Enthusiast

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    Thats pretty poor but this time of years its not unusual to get poor figures on shorts trips

    First point of call would be a new air filter , these often get forgotten but i change mine once a year or every 10,000 miles , i find performance and economy drop off otherwise

    I doubt you will ever see 47 mpg though , low 40's is pretty good in my experience
     
  4. Gareth

    Gareth Hardcore MB Enthusiast

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    driving over a long distance at 70mph I've seen my E280 CDI do 42mpg.
     
  5. x332race

    x332race Hardcore MB Enthusiast

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    Try using some Millers diesel Power plus......I found this helped to clean the engine on my car when I bought it.....also good advice to repalce the air filter. You should be getting better mpg than you are achieving.....average should be at least 30mpg wiht over 40mpg on long journeys.
     
  6. ceejay

    ceejay Active Member

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    I have exactly the same car, and 33mpg whilst not good, isn't unbelievable if you have a portion of urban driving in the mix. I would expect you to get around 36+mpg (from the cluster) for that length of journey as a minimum, potentially over 40 if you are light footed.

    As regards inserts in the wings, do you mean plastic wheel arch liners? If so, the answer is yes, there should be some.

    Chris
     
  7. Gareth

    Gareth Hardcore MB Enthusiast

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    yeah I think he does mean the arch liners, in which case there definitely should be some.
     
  8. jeremytaylor

    jeremytaylor Hardcore MB Enthusiast

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    In my E320 CDI, driving at 65mph for 60 miles on the motorway I would be getting 45-ish. But the computer takes an average reading from the start of the journey, and if I had to drive at 12mph through heavy traffic for an hour beofre getting to said motorway, the computer read-out after 60 miles at 65mph would be lower.

    And yes the front wings should have black plastic liners (don't all cars these days?) - I would suspect poorly repaired accident damage?
     
  9. V12

    V12 MB Club Veteran

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    If i drive 60 miles at around 65mph it returns over 40mpg no problems, can even edge up past 45mpg on a good day in ideal circumstances.

    In reality when checking the cluster against a fill up mpg test, the cluster is always approx 12% more optimistic than what i really get.
     
  10. maddog

    maddog Hardcore MB Enthusiast

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    I've had my W210 for 7 years now and i have only ever had more than 42mpg once and that was when i was almost out of fuel driving at 50mph with everything electrical off, panic mode !!:)

    My car has the two main cats removed although this hasnt altered the mpg and has a fairly high standard spec including 235/45/17 tyres

    I find a decent motorway trip driving at 80mph ish will yield 38/39 mpg. I rarely reset my average mpg display and in the winter it reads 33.5mph average and in the summer 34.5mpg

    Recently i drove from Derby to Berkshire , all motorway, nice and clear doing a steady 60-70 mph and barely tickling the throttle (the car had just been fully serviced and new air filter fitted)

    [​IMG]

    Thats as good as mine every gets

    Checking my fuel computer against the old fashioned paperwork method and its about right although historically its more accurate on longer trips rather than short journeys
     
  11. V12

    V12 MB Club Veteran

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    All 3 of the 320cdi's we have all return almost identical figures (to what yours gets maddog) at the pump check, despite varying trim level/wheels ranging from 16" to 19"

    One of them is spot on with the OBC like yours, the other two are way out...
     
  12. V12

    V12 MB Club Veteran

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    Last edited: Dec 11, 2008
  13. Peter DLM

    Peter DLM Hardcore MB Enthusiast

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    My W210 320 petrol has averaged 29mpg over the last 2,200 miles, and I live in the middle of London.

    On a run it'll average 32mpg. I don't drive slowly either, I tried it once but didn't like it.

    Though this is the result from the car's own calculations, not my own.

    I'd have thought that a diesel would be at least 10mpg better.
     
  14. maddog

    maddog Hardcore MB Enthusiast

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    Probably would if it didnt have a turbo

    Interesting to hear from someone that the wide tyres dont make the difference i've been led to believe , someone once told me they cost 4mpg ,

    In addition i will add my car had a Van Aaaken tuning box fitted until recently. I fitted it when the car had done about 20,000 miles and saw an increase in range approx 1mpg both around town and on a run, i recently removed this to do another comparison in case the difference i saw was down to the engine settling in as 20k isnt a lot on a 3.2 engine

    Over the last 3000miles my averages have been about the same , with the tuning box the car is slightly better on fuel when driven faster presumably because it gets up to speed quicker, around town and when cold it is quite a bit worse on fuel with the tuning box , but on average its still about 1mpg better than without.
     
  15. Gareth

    Gareth Hardcore MB Enthusiast

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    ah interesting point, my E280 CDI has the Sport 18"s (245 f 265 r ) on it.
     
  16. V12

    V12 MB Club Veteran

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    There are so many factors to take into consideration it's not even worth thinking about, but i drive the same journey every day and after 3 months of using my e320cdi (fr 235/35/19 re 285/30/19) and then 2 months in another 320cdi (215/55/16 al round) i saw absolutely no difference whatsoever in economy, in most situations the economy really comes down to driver and journey.

    On a sidenote about tyres - if your car stays the same weight and the tyres are lower profile, the contact patch should stay the same i would think? Which means the same resistance and same economy. If the tyre is wider and lower profile the contact patch will be wider, but not as long as the original. I'm not sure if this is entirely correct, but i stand by my statement that wider tyres don't really effect economy.
    ___ . . _______
    I...I or I_____ I
    I...I
    I__I

    Main things i do to keep my economy up are
    -check tyre pressures once a week
    -never carry any excess items
    -thoroughly service the vehicles myself regularly.
     
    Last edited: Dec 11, 2008
  17. OP
    OP
    r11pak

    r11pak New Member

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    Hi Guys...This forum stuff is amazing...im suprised to see so many excellent responses so quickly.

    Right..The car warms up and stays around 80-85 degrees within 5 miles of driving about (15 minutes town)
    I reset the cluster when I was at 60mph on the motorway just feathering the trottle and was getting the 33mpg...I have checked back with the number of litre I have put in and I know this is a little optimistic.

    The car has a 119K on the clock
    I rang up the Cambridge mercedes where it had been previously serviced and they told me that along with the oil they resolved a misfire issue from cylinders 1 and 2 in april using new injector seals and bolts. And that this had resolved the issue.

    Maybe I need to take the plastic cover of and see if it leaking diesel!?

    Its just a shame to have a new (well 7 year old) car with full MB service that has fuel issues.

    regarding the plastic inserts I was refering to the front arches....I called up MB and they said that there is nothing for the W210 to put in the arches....no wonder they bubble up so quickly! :S

    Diesel Benz: not sure If i need new injectors they are all very quite....and even at night on kickdown I get hardly any smoke at all...it seems ok.

    Maddog: I would love to get that sort of mpg...yet to be seen! lol

    thanks again.
     
    Last edited: Dec 11, 2008
  18. WJR

    WJR New Member

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    Your fuel consumption doesn't look good to me. Most of my journeys are in a central London traffic jam, and I rarely get above an average 9 mph. For these I usually manage 22 mpg. If I'm on a motorway at 70 mph, I usually achieve low to mid forties.
     
  19. ringway

    ringway MB Club Veteran

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    Oh Dear, I had my 02 front wings replaced under MB warranty and they made a cracking job of them. But I did notice they don't have any plastic linings and I thought about waxoyl.
    Now I will take the car back to the MB bodyshop. Many Thanks Guys.
     
  20. ringway

    ringway MB Club Veteran

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    I have been told I need a new thermostat - my car stinks of unburnt fuel is not as economical as it used to be and has been losing power sometimes, as though the turbo has gone. I had no idea the thermostat not working could have an impact on fuel economy. I'll let you know the results when I have collected Fri/Mon
     

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