Poorly ML320 (2003) Petrol

Discussion in 'Engine' started by curlyearly, Sep 30, 2011.

  1. curlyearly

    curlyearly Member

    Messages:
    55
    Joined:
    May 28, 2008
    Location:
    Stoke-on-Trent
    Car:
    ML320
    I have an on going issue with my vehicle. I have posted an earlier reply which got some positive responses. Alas these replies also asked questions so in the meantime I have been able to add further information which may light the way.

    Problem:

    A, Cold.... Always starts fine. Should I attempt to pull away on a cold engine it feels like its running on three cyclinders. The power loss is such that the car comes to a halt on the flat. Give it twenty seconds to stabilise and it fine. Alternatively I can leave the car to tick over for 2-3 minutes and its fine.

    B, Warm....When starting the engine tries to cut out. It feels like its not running on all cyclinders.

    Attempted Solution:

    The vehicle has been to three garages; one that has done my servicing for the majority of the last twenty years, a MB non-franchised specialist and a franchised MB dealership. And heres the kicker; using their skill and electronic gadgetry they all pinpointed the same remedies which they undertook on an increasing pound basis. Changed are; plugs (all), plug leads (all), coils (all) and two sensors. I think one was a crank sensor. In some cases the subsequent garages poo-pooed their predessosors by saying plugs / leads fitted were'nt the correct ones but I think this is merely a personal preference. Nethertheless all three garages changed all listd items (thats 3x everything all and alot of money - I was fed up at first and desperate at the end). Still not fixed. I've been told, "we dont know" and " go away and see if the problem goes away". In essence its not fixed.

    A question asked to me:

    Q, What were the codes the garages worked from?
    A, Sorry I dont know but there were several.

    Updated Info

    I bought a Memoscan U381 from Ebay which can list codes. Below are the codes listed today...

    PO 131 - 02 Sensor circuit low voltage volts (bank 1 sensor 1).
    PO 135 - 02 sensor heater circuit malfunction (bank 1 sensor 1)
    PO 155 - 02 Sensor heater circuit malfunction (bank 2 sensor 1)

    All replies greatfully received, cheers all
     
  2. dog68

    dog68 Hardcore MB Enthusiast

    Messages:
    629
    Joined:
    Jul 18, 2010
    Location:
    cambridgeshire
    Car:
    Mercedes s500
    Anyone look at, or change the 02 sensor? I take it the garages had star?
     
  3. OP
    OP
    curlyearly

    curlyearly Member

    Messages:
    55
    Joined:
    May 28, 2008
    Location:
    Stoke-on-Trent
    Car:
    ML320
    o2 sensor

    To my knowledge no. I can find no record of this. I've looked on Ebay and they're about £100, is this correct?

    Furthermore it suggests the task is an easy DIY project, any comments on this?

    Cheers mate for your reply.
     
  4. Alex Crow

    Alex Crow Hardcore MB Enthusiast

    Messages:
    278
    Joined:
    Sep 30, 2011
    Location:
    Super Suffolk
    Car:
    S210 320cdi
    sounds like fun, did any of these garages consider that the airmass sensor might be to blame? very common on this engine, and with your described symptoms...

    alternatively, working with the fault codes you have would mean checking lambda sensor function and supply voltage/earth etc. i have a nagging suspicion that i know something else about this one, but cannot remember it...

    one more thing, do you have LPG installed?
     
  5. OP
    OP
    curlyearly

    curlyearly Member

    Messages:
    55
    Joined:
    May 28, 2008
    Location:
    Stoke-on-Trent
    Car:
    ML320
    Reply

    Yes I have LPG installed. I have had the system totally electrically disconnect without success. At the moment its connected however what were your thoughts?

    Any what about your nagging other thought?
     
  6. NW_Merc

    NW_Merc Banned

    Messages:
    5,918
    Joined:
    Sep 3, 2005
    Location:
    Over here, sometimes over there
    Car:
    1994 Mercedes C180 classic
    Has it got a MAF sensor? Has this been changed?
     
  7. Alex Crow

    Alex Crow Hardcore MB Enthusiast

    Messages:
    278
    Joined:
    Sep 30, 2011
    Location:
    Super Suffolk
    Car:
    S210 320cdi
    i have seen problems with these before when running on gas, the self adaptation moves way out (due to LPG injector faults or blocked gas filters or somesuch).
    this causes major running issues on petrol, similar to those you describe.
    one thing that may be worth trying is resetting the self adaptation back to zero, and running solely on petrol for a period.

    if resetting self adaptation makes it run far worse, we must suspect that obvious air mass sensor that has not been changed.

    to reset self adaptation on this model, simply disconnect the battery for 1/2 hour or so, and as i say, run on petrol only for a while.
     

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