What is the abnormal noise of BMW n20 engine?

The following are the reasons for abnormal noise of BMW n20 engine: the engine has serious carbon deposit: the most common reason for abnormal noise of engine is that the throttle is too dirty or the fuel injector has too much carbon deposit. Solution: Clean the oil circuit, check whether the idle motor has carbon deposit and clean it. Ignition system problem: this phenomenon may also be caused by poor ignition system and poor ignition conditions of spark plugs. Solution: Check the spark plug for excessive carbon deposition and replace the spark plug. Unstable oil pressure: Abnormal oil supply pressure of oil pump, incorrect intake pressure sensor value and poor operation will all cause abnormal engine noise. Solution: Check the oil pressure and replace parts if necessary.