M54 rattle!!

Diese Seite verwendet Cookies. Durch die Nutzung unserer Seite erklären Sie sich damit einverstanden, dass wir Cookies setzen. Weitere Informationen

  • M54 rattle!!

    Hi there.
    As I was leaving work this afternoon I noticed my car was violently shaking as soon as it started up with the check engine light on. The shaking decreases when revving but it's still noticably there. Idle rpms are fairly solid at 700 but the throttle seems to lag behind a bit, it also feels fairly underpowered. This tells me a cylinder (or more) is misfiring but to me it sounds like valves ticking. I've recently changed the oil (about 500km ago) so that might have something to do with it? Idk.
    I've checked Google and I've found about a hundred possible causes including, but not limited to, vanos failure, vacuum leaks, injector failure, ...
    I've also watched a couple of videos but none seem to match the sound mine makes: imgur.com/gallery/GuXnOpu
    I've left the car at work and I'll check for fault codes with an odb scanner (that'll hopefully work this time..) tomorrow but it'd be nice to have your guys's thoughts on this.
  • The video is your engine? If so, does the shaking appear on gas and lpg? Or is it stronger on lpg than on gas?
    This looks like a dead spark plug or ignition coil. Have you any option on obd check to see on which cylinder the misfire is happening (and if it may be traveling with changing plugs or coils to another one)?
    I would get new sparks (not too expensive, full ngk set ~30€ on ebay) and I guess it will be 1 new coil. If you are at it and want to spend the money, change all. The next failure might be soon. For me it was half a year between two failing coils, but I know a few guys where only one broke down and the others are still working fine.
    Injectors might be a problem as well, but that should only appear on one fuel source since the other injectors should be fine (or it would be really bad luck failing both at the same time).
    VANOS or vacuum leaks normally do not show such a big shaking, it is more about power loss.
  • Generic OBDt scanners usually don't work too well on the E39, the car is simply too old. But as @VincentVega already said, it should be able to show you if one cylinder is running more roughly than the other ones, and which one it is. Take off that coil and change places with the adjacent coil. If the neighbouring cylinder is now running rougher, that's your defective coil.

    Changing your oil won't cause such troubles. Which weight did you put in?

    How does the "underpowered" feel like, in what situations?

    It might also help if you added a bit more detail about your car ...