susanwerner56

M Klasse hybrid engine knocking combustion issue

I'm experiencing a troubling issue with my 2011 Mercedes M Klasse hybrid. With only 18905 km on the odometer, the engine suffers from what I believe is a knocking combustion. Symptoms include reduced engine power, a noticeable jerking during acceleration, and visible smoke emitted during acceleration. An error is also stored in the error memory. Could this be related to deposits in the combustion chamber?

4 comment(s)

Sounds rough. I had something similar happen with my M Klasse. Is it a rhythmic engine knock, almost like piston slap? Check your ignition timing too. Could be running too advanced. I'd also try some fuel injector cleaner, might help if it's just buildup in the combustion chamber. Have you tried any engine tuning or is everything factory?

Thank you for your quick response. It does sound like a rhythmic knock, yes. How did you resolve the issue when you experienced it? And did you also have smoke when accelerating?

Mine was definitely combustion chamber deposits. Symptoms were pretty much the same as yours. The smoke was a big clue. I ended up taking it to a workshop; they used some special cleaning agents to remove the deposits. Best to get it checked out before it causes any serious damage.

Thank you for sharing your experience. I appreciate the advice and will take the car to a workshop for inspection and cleaning of the combustion chamber. The estimated repair cost is 425€. Hopefully, this will resolve the issue.

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