FixVault

Compression Pressure

With battery fully charged, engine at normal operating temperature, throttle fully open and engine at cranking speed, compression pressure should be as follows:

NOTE: Deactivate fuel injection system by pulling off connection "V at the coil prior to compression test.
Compression Pressure

Application Pressure
528i
  Good Above 156 psi (11 kg/cm2 )
Normal 142-156 psi (10-11 kg/cm2 )
Poor Below 142 psi (10 kg/cm2 )
633CSi & 733i
  Good Above 142 psi (10 kg/cm2 )
Normal 121-142 psi (8.5-10 kg/cm2 )
Poor Below 121 (8 kg/cm2 )