Engine Compression

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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