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Home >> Jaguar >> 1994 >> XJ-6 L6-4.0L >> Repair and Diagnosis >> Maintenance >> Tune-up and Engine Performance Checks >> Compression Check >> Testing and Inspection
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Compression Check: Testing and Inspection

1. Start and run engine until it reaches normal operating temperature.
2. Relieve fuel system pressure as outlined under "Precautions".
3. Place transmission in the Park position, then disconnect ignition coil high tension cable.
4. Remove spark plugs and install pressure gauge.
5. Crank engine at 300 RPM and check compression.
6. Compression should be 160-170 psi, maximum variation between cylinders must not exceed 10 psi.