Engine Compression
Deactivate fuel injection system by pulling off connection "1" at the coil prior to compression test. With battery fully charged, engine at normal operating temperature, throttle fully open and engine at cranking speed, compression pressure should be as follows:
COMPRESSION SPECIFICATIONS
| Compression Ratio | |||
| 528e | 9.0:1 | ||
| 633CSi | |||
| Man. Trans. | 8.4:1 | ||
| Auto. Trans. | 8.0:1 | ||
| 733i | 8.0:1 | ||
| Compression Pressure | |||
| 528e | 142-156 psi (10.0-11.0 kg/cm2 ) | ||
| 633CSi & 733i | |||
| Good | Above 142-185 psi (10.0-13.0 kg/cm2 ) | ||
| Normal | 121-142 psi (8.5-13.0 kg/cm2 ) | ||
| Poor | Below 114 psi (8.0 kg/cm2 ) | ||