[papachivas]

Measurements done. No cylinder is below 12 Bar / 180 PSI.

Hello friend for the BMW that use the N63 engine we have many problems.
The most common.
Spark plugs. For spark plugs I always use NGK Bosch I always have problems. Never forget to use the I'm torquemeter and apply the correct torque to the spark plugs. Ignition coils. All air intake ducts and ventilation tubes are recessed to replace.
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Here is good video that someone in shop did

Spark plugs are a very important component in the engine's ignition system, let alone the N63 engine. So pay special attention to them before installing always make sure that  the electrodes are at the correct distance (gap) so make sure to check and calibrate if necessary with a suitable tool.
High pressure pumps pay attention with pre filter in the fuel inlet. if you notice that it is damaged, remove it, if the mesh (sieve) is completely destroyed, replace the pump   related high pressure fuel and all fuel injectors from the same bench if both high pressure fuel pumps have the same problem replace both and all engine fuel injectors(8).
To make sure all injectors are tight or leaky you can monitor high fuel pressure with ISTA after the engine has been at operating temperature for a while. period of at least 30 minutes or after a good test drive.
If the pressure continues to rise after switching off the engine on both benches, that's good, but don't rule out the possibility that one or the other of the injectors is not leaking.  So here when I have persistent problems related to the fuel and ignition system I remove them all the injectors I connect them all to each of the high pressure fuel pumps so that the fan part of the injectors is outside the engine and start the engine and observe if any of them are 100% tight or if any of them starts to leak gasoline.NOTE: Never do this if you are not an experienced technician.
REMOVE ELECTRICAL POWER SUPPLY FROM IGNITION COILS. YOU ARE DEALING WITH HIGH FIRE RISK FUEL SYSTEMS.
REMOVE ELECTRICAL POWER SUPPLY FROM ALL INJECTORS.
HERE I TURN ON ONE INJECTOR EVERY TIME TO INSPECT THE FAN AND REMOVE POSSIBLE AIR JUST FOR A FEW SECONDS PER INJECTOR .
IF YOU INTEND TO DO THIS IT IS AT YOUR OWN RISK.
I'm just reporting what I do when I have ongoing issues with these engines.