NBox Knocking Combustion

Your symptoms do sound familiar. I encountered comparable issues with my previous vehicle, a 2018 Opel Astra, also gasoline. The jerking, loss of power and error code, particularly in conjunction with the knocking combustion, suggest potential pre-ignition. Have you considered the possibility of carbon deposits accumulating within the combustion chamber? Pre-ignition occurs when the air-fuel mixture ignites prematurely due to hotspots created by these deposits. This can lead to engine knock. Have you checked the knock sensor?

Carbon deposits, huh? I haven't looked at that specifically. Is there a way to check for those myself, or is that something I'd need to take it to a workshop for? And the knock sensor, where is that located? I'm pretty handy, but I'm not a mechanic by any means.

Verifying carbon deposits directly is difficult without specialized equipment like a borescope to visually inspect the cylinders. However, the presence of smoke and knocking combustion strongly points in that direction. The knock sensor is typically mounted on the engine block, cylinder head, or intake manifold. Its purpose is to detect engine knock and retard ignition timing to prevent damage. If the sensor is faulty, it may not accurately detect knock, leading to the symptoms you are experiencing. However, considering the complexity, potential damage to cylinder heads, and your description, I would advise seeking professional evaluation at a reputable workshop.

Thanks for the detailed explanation! I took it to a mechanic, and you were spot on – it was carbon deposits in the combustion chamber. They cleaned it out, and the knocking is gone. Cost me 425€, but worth it to have it running smoothly again!