
The need to adjust the clearances in the valve drive is evidenced by a distinct loud knock heard when the engine is idling from the driver's seat with the hood closed

The high pressure fuel pump (TNVd) is driven by gears from the rear end of the crankshaft.
The pump housing also has a mechanical booster pump that draws fuel from the tank.

Checking and setting the TDC of the first engine cylinder in the compression stroke is necessary when performing work on removing the camshaft drive chain