Mechanical Inspection: Compression: Notes
Check engine mechanical condition with a compression gauge, vacuum gauge or an engine analyzer. See engine analyzer manual for specific instructions. Always disconnect the engine speed/reference sensor for compression tests. If this is not done, dangerous high voltages and insulation damage to the following may result: ignition coil, high-voltage distributor, and ignition leads.
WARNING:
DO NOT
use ignition switch during compression tests on fuel- injected vehicles. Use a remote starter to crank engine. Fuel injectors are triggered by ignition switch during cranking mode and can create a fire hazard or contaminate engine's oiling system.
ENGINE COMPRESSION
| Application | psi (kg/cm2 ) |
|---|---|
| Normal Compression Pressure | 142-184 (10-13) |
| Minimum Compression Pressure | 107 (7.5) |
| Maximum Variation Between Cylinders | 22 (1.5) |