Mechanical Inspection: Compression
Check engine mechanical condition with a compression gauge, vacuum gauge, or engine analyzer. See engine analyzer manual for specific instructions.
WARNING:
DO NOT use ignition switch during compression tests on fuel injected vehicles. Use a remote starter to crank engine. Fuel injectors on many models are triggered by ignition switch during cranking mode, which can create a fire hazard or contaminate the engine's oiling system.
COMPRESSION SPECIFICATIONS
| Application | Specification | |
|---|---|---|
| Compression Ratio | ||
| Storm (SOHC) | 9.1:1 | |
| Storm GSi (DOHC) | 9.7:1 | |
| Normal Compression Pressure | ||
| Storm (SOHC) | 159 psi (11.2 kg/cm2 ) | |
| Storm GSi (DOHC) | 170 psi (12.0 kg/cm2 ) | |
| Minimum Compression Pressure | ||
| Storm & Storm GSi | ||
| Maximum variation between cylinders is | 14 psi (1.0 kg/cm2 ). | |