Checking Compression Of All Cylinders
WARNING: This page is about a different car, the 2003 BMW 530i, 2002 BMW 530i, and 2001 BMW 530i. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
High tension - mortal danger!
Cut off power supply to ignition coils (disconnect plug connection at DME control unit).
Necessary preliminary tasks:
- Connect charger or a second battery.
- Read out fault memory of DME control unit
- Pull fuel pump relay or fuel pump fuse.
- Start engine and allow residual fuel to drain out (pressure reduction).
- Remove all spark plugs. See 12 12 011 REPLACING ALL SPARK PLUGS
IMPORTANT:
Check Schrader valve on special tool 11 0 226 for tight fit.
Screw special tool 11 0 226 by hand into spark plug thread and connect special tool 11 0 224.
NOTE:
Check that sealing ring is in perfect condition (see arrow).
Depress accelerator and actuate starter until compression stops rising.
Compression pressure.
Assemble engine.
Now clear the fault memory.