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Home >> Infiniti >> 1995 >> J30 >> Repair and Diagnosis >> Engine Performance >> Engine Controls - Specifications 3.0L >> Mechanical Checks >> Engine Compression >> Compression
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Engine Compression: Compression

Check engine compression at normal operating temperature at specified cranking speed. Release fuel pressure. See FUEL SYSTEM  . Disconnect crankshaft position sensor harness connector. Remove all spark plugs. Depress accelerator pedal fully to hold throttle valve wide open. See COMPRESSION SPECIFICATIONS  table.

NOTE: If cylinder compression in one or more cylinders is low, repeat inspection using a small amount of oil poured into each cylinder. If compression pressure increases, piston rings may be worn or damaged. If compression pressure does not increase, a valve may be sticking or seating improperly. If compression in any 2 adjacent cylinders is low and does not change after oil is added, there is a leak past head gasket. Make repairs as needed and reinspect.
COMPRESSION SPECIFICATIONS (1)

Application psi (kg/cm2 )
Standard 186 (13.1)
Minimum 142 (10.0)
Maximum Variation Between Cylinders 14 (1.0)
(1) Readings taken at cranking speed (300 RPM).