Engine Compression

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Check engine compression under the following conditions: engine at normal operating temperature and specified cranking speed, all spark plugs removed, and throttle wide open.

COMPRESSION SPECIFICATIONS

Application

Specification

Compression Ratio

3.1L (VIN T)

"F" Body

8.5:1

All Others

8.8:1

3.3L (VIN N)

9.0:1

3.4L (VIN X)

9.25-9.50:1

3.8L (VIN C & L)

8.5:1

Normal Compression Pressure

⁽¹⁾

Minimum Compression Pressure

⁽¹⁾

⁽¹⁾	The lowest compression reading should not be less than 70 percent of the highest compression reading. No cylinder compression reading should be less than 100 psi (7 kg/cm² ).