Engine Compression
Check engine compression with engine at normal operating temperature at specified cranking speed, all spark plugs removed (on dual plugs, remove exhaust side only) and throttle wide open.
NOTE:
Compression pressure and cylinder pressure variation for 2.5L and 4.0L engines are not available from manufacturer.
COMPRESSION RATIO
| Application | Specification | |
|---|---|---|
| 2.5L | ||
| Cherokee & Comanche | 9.2:1 | |
| Wrangler | 9.1:1 | |
| 4.0L | 8.8:1 | |