backfire ??

Discussion in 'Engine' started by Braincrank, Jun 24, 2017.

  1. Braincrank

    Braincrank Hardcore MB Enthusiast

    Messages:
    360
    Joined:
    Sep 12, 2012
    Location:
    West London
    Car:
    Mercedes 200E
    I wonder if anyone could point me in the right direction as to where to start ...
    For quite some time now I notice that when I drive on the motorway and I take my foot of the gas then from 2.5k to 2k rpm the engine dose a ticking noise that sounds like a little backfire ...
    As soon as the refs get below 2000 it stops .
    Any idea what that might be ?
    200E, auto, 124
     
  2. OP
    OP
    Braincrank

    Braincrank Hardcore MB Enthusiast

    Messages:
    360
    Joined:
    Sep 12, 2012
    Location:
    West London
    Car:
    Mercedes 200E
    I'm still at a loss .....
    anyone out there who might have a clue ?


    Sent from my iPad using Tapatalk
     
  3. 190

    190 Hardcore MB Enthusiast

    Messages:
    2,824
    Joined:
    Mar 4, 2015
    Location:
    Cheshire
    Car:
    2009 W204 C180K
    Not sure if this helps. If we are talking about Bosch Ke fuel injection then it should have fuel cut off on the overrun above a certain engine speed which I would have thought precludes backfires. When the revs fall below a defined point the fuel kicks back in again. This transition was just about perceptible on my 190e although I think it was at less than 2000 RPM. I'm wondering if your fuel cut off is not working as it should.
     
  4. OP
    OP
    Braincrank

    Braincrank Hardcore MB Enthusiast

    Messages:
    360
    Joined:
    Sep 12, 2012
    Location:
    West London
    Car:
    Mercedes 200E
    Hm, thanks for your reply.
    It only started doing it about 10 months ago ...
    The car runs and idles fine and i have not problems with it .


    Sent from my iPad using Tapatalk
     
  5. alabbasi

    alabbasi Hardcore MB Enthusiast

    Messages:
    1,335
    Joined:
    Feb 18, 2008
    Does it happen only when warmed up or also when cold? When coils fail (usually when hot) they'll start falling on their face under load.
     
  6. grober

    grober MB Club Veteran

    Messages:
    27,060
    Joined:
    Jun 22, 2003
    Location:
    Perth, Scotland
    Car:
    W204 C200CDI Estate
    This only applies the car has the single cam M102 ENGINE

    http://www.berlinasportivo.com/Technical/lancia/Thema832/Bosch-KE-Jetronic-OCR.pdf

    page 23 describes fuel cutoff on the overrun.

    A backfire refers to fuel igniting where it shouldn't not in the cylinder but in the inlet or exhaust. I suspect that the overrun cutoff may not working properly allowing unburnt fuel into the hot exhaust where its igniting. This could be caused by several things throttle position switch and possibly more likely the electro-hydraulic pressure actuator
     
    Braincrank likes this.
  7. OP
    OP
    Braincrank

    Braincrank Hardcore MB Enthusiast

    Messages:
    360
    Joined:
    Sep 12, 2012
    Location:
    West London
    Car:
    Mercedes 200E
    I don't even know if it is a backfire ....
    It's a sort of ticking noise .
    I revved the engine to 3k rpm at standstill and when I took the foot off the pedal I could hear is for a second . It lasts much longer when driving because the car takes longer to slow down and the revs go down slower .


    Sent from my iPad using Tapatalk
     
Tags:

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.