Compression Check: Testing and Inspection

Checking compression of all cylinders (N12, N14)


- Read out fault memory of DME control unit
- Check stored faults
- Rectify faults
- Clear fault memory


Important:
High tension - mortal danger!
Interrupt power supply to ignition coils.
Read and comply with notes on compression pressure check.


Necessary preliminary tasks:
^ Remove spark plugs.



Unscrew tip (1) from special tool 11 0 222.

Important:
Then check the Schrader valve that is now visible for secure seating.





Prepare special tool 11 0 222 in conjunction with 11 8 732 and 11 8 731.





Screw special tool 11 0 222 onto special tool 11 8 731 to 10 Nm.





Important:
Do not forget to oil spark plug thread of special tool 11 8 731.

Screw special tool 11 0 222 by hand into spark plug thread and connect special tool 11 0 224.

Use adapter lead (1) if the compression pressure is being checked with the BMW diagnosis system.
Depress accelerator pedal and actuate starter until compression pressure stops rising.

^ Nominal values, compression pressure





Assemble engine
Now clear the fault memory.