The engine is experiencing a banging sound.

[Liveek]

Greetings, everybody.
As seen by the link provided, my engine has developed a knocking sound when idling, which ceases while accelerating. When I disable the fuel delivery to the fourth cylinder, the sound seems to become more stable. However, I am uncertain if the issue is with the injector itself or whether it indicates a more serious problem. Prior to attempting removal, I would want to inquire whether anybody has already had a similar scenario. Thank you in advance

 

 

[Cincoon]

It is difficult to determine from the video due to the typical noise of a diesel engine. However, based on your description, it seems to closely like the sound of the N47 engine in my wife's previous vehicle when I purchased it. The large end bearing for cylinder number 4 has experienced spinning and significant erosion, resulting in complete wear. Require a new rod and crankshaft.

[Liveek]

If the issue lies in the large end bearings, would I not perceive a corresponding escalation in the ticking sound as the revolutions per minute (rpm) of the engine increase? As the engine speed reaches around 1000rpm, the knocking noise ceases.

[Cincoon]

Typically, one would do such. I failed to perceive your statement on the phenomenon of disappearance when speeding. It may be beneficial to temporarily exchange injectors 1 and 4 and restart the engine to see whether the noise shifts to cylinder 1.
I suspected that my engine's fuel injector was also faulty, since the symptoms did not like the typical signs of previous major engine failures I had experienced in the past. I discovered metal fragments after draining the oil, so I removed the engine and disassembled it.

[Thenornpo]

Most likely the issue is either with the large end or a piston.

[Carishme]

If the noise ceases while accelerating, as stated by the original poster (OP), then it is unlikely to occur.

[Liveek]

Upon attempting to detach the alternator belt and just rely on the battery, I saw a complete cessation of the noise. Attempted to replace all the pulleys, tensioner, and belt, but did not achieve any improvement. When the belt is installed, the vehicle produces a knocking sound, which is rather peculiar.
The water pump, alternator, and crankshaft pulley seem to be in acceptable condition. Do you have any suggestions or thoughts?

[Liveek]

I attempted to create a video showcasing two distinct scenarios. It operates seamlessly without the need of a belt.

 

 

[Liveek]

Essentially, I would want to inquire if it is conceivable for a potential issue with the large end bearing to only become apparent when the dumper is tightened with the belt, and everything seems to be OK while the damper is not under strain. While the sounds typically produced by a defective water pump, compressor, alternator, or damper vary from the ones I am experiencing, is it possible that one of these components may still be the source of my issue?

[Liveek]

???🫠