w202 - Running Rough

Discussion in 'Engine' started by ozzy_c180, Sep 25, 2008.

  1. ozzy_c180

    ozzy_c180 New Member

    Messages:
    13
    Joined:
    Sep 19, 2008
    First of all thanku to everyone who assisted me....

    My car finally starts with a new key, however Mechanic states that it is running rough even when he revs it makes a poping noise and it doesnt accelrate. It has been parked for a month never had a problem like this before...He thinks its some air pump... any ideas.... Please.. Or is he trying to make more money out of me...
     
  2. Leemc2008

    Leemc2008 Hardcore MB Enthusiast

    Messages:
    524
    Joined:
    Jul 21, 2008
    Location:
    Cornwall
    Car:
    BMW e39 540i 4.4 V8
    It sounds like MAF sensor..

    Mass Air Flow sensor.. works out how much air is coming into the car and works with the ECU to control the amount of fuel going into the engine..

    If faultly the car will run poorly.. over or underfuelling and generally very poor running.. bad or no idle.
     
  3. recycled

    recycled Hardcore MB Enthusiast

    Messages:
    4,278
    Joined:
    Feb 26, 2007
    Have you tried unplugging the MAF sensor first to see if it improves?
     
  4. grober

    grober MB Club Veteran

    Messages:
    26,500
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
    A popping noise can be indicative of excess unburnt fuel in the exhaust. Some cars have an air pump which injects air into the exhaust to burn up this access fuel under certain running conditions e.g. on the overrun. It's part of the emissions control system in some cars in some parts of the world but I am unfamiliar with it on your car. Your mechanic could be correct but there are many other reasons why your fuel/air mixture is not correct. Ranging from the ECU to the lambda sensor to the inlet MAF to the engine temperature sensor. You need to get the engine fault codes read to see what's causing the problem.
     
  5. OP
    OP
    ozzy_c180

    ozzy_c180 New Member

    Messages:
    13
    Joined:
    Sep 19, 2008
    How do I disconnect the MAF sensor, and if i was to get a new one how much do they usually cost i.e Part + Labour. My car has been parked up for a while and during this time i have tried numerous time s to start it.. can this cause the fuel overflow. Thanks
     
  6. OP
    OP
    ozzy_c180

    ozzy_c180 New Member

    Messages:
    13
    Joined:
    Sep 19, 2008
    Hi,

    I have been told its the RPM Sensor...Whats this please
     
  7. grober

    grober MB Club Veteran

    Messages:
    26,500
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
    Don't recognise the description- might be the crankshaft position sensor? Normally if they go faulty the engine just dies.
     
  8. Howard

    Howard MB Club Veteran

    Messages:
    18,624
    Joined:
    Apr 23, 2004
    Location:
    Toad Hall
    Car:
    CLS 500 / A 150
    Might they mean the MAS Graeme ?

    As RPM increases so will airflow , so perhaps they mean this ?
     
  9. OP
    OP
    ozzy_c180

    ozzy_c180 New Member

    Messages:
    13
    Joined:
    Sep 19, 2008
    Hi,

    Where is the cranck shaft position sensor located

    Thanks
     
  10. recycled

    recycled Hardcore MB Enthusiast

    Messages:
    4,278
    Joined:
    Feb 26, 2007
    it is not the crankshaft sensor. the car will not start if it is this.
    the maf sits on top in between the air filter and the engine intake.A black plastic culinder with a plug on top of it.
     
  11. grober

    grober MB Club Veteran

    Messages:
    26,500
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
    Don't think so Howard but who knows? Other possibility is the camshaft position sensor or the throttle plate position sensor??:confused:
     
  12. OP
    OP
    ozzy_c180

    ozzy_c180 New Member

    Messages:
    13
    Joined:
    Sep 19, 2008
    hey guys...

    Thanks it was the MAF sensor.... But one more problem... car was working f9 and the alarm went of the other day and now the central locking does not work... any ideas.. thank u for ur help so far
     
  13. Dieselman

    Dieselman Banned

    Messages:
    34,206
    Joined:
    Jul 13, 2003
    Car:
    Peugeot 403 Convertible
    Try disconnecting the battery or alarm to reset it.
     
  14. OP
    OP
    ozzy_c180

    ozzy_c180 New Member

    Messages:
    13
    Joined:
    Sep 19, 2008
    Thanks disconnecting the battery worked....
     
  15. reflexboy

    reflexboy Hardcore MB Enthusiast

    Messages:
    2,393
    Joined:
    Feb 23, 2005
    Location:
    Surrey, UK
    Car:
    E350 CDi Sport&SLK250CDi AMG Sport
    Boy, I bet you are glad you joined this forum:D
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.