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Checking Compression Pressure

WARNING: This page is about a different car, the 2009 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.
  1. Run the engine until it reaches normal operating temperature.
  2. Turn the ignition switch to OFF.
  3. Release fuel pressure and leave the fuel pump electrically disconnected. Refer to "INSPECTION ".
  4. Remove all six spark plugs. Refer to "REMOVAL AND INSTALLATION ".
  5. Attach a compression tester to No. 1 cylinder.
    Fig 1: Identifying Compression Gauge
    G04885696Courtesy of NISSAN MOTOR CO., U.S.A.
  6. Depress accelerator pedal fully to keep the electric throttle control actuator butterfly-valve wide open to maximize air intake flow.
  7. Crank the engine and record the highest gauge indication.
  8. Repeat the measurement on each cylinder (steps 5 - 7).
    • Always use a fully-charged battery to obtain specified engine speed. 

      Unit: kPa (kg/cm2 , psi)/RPM

    COMPRESSION PRESSURE SPECIFICATION

    Standard Minimum Difference limit between cylinders
    1,275 (13.0, 185)/300 981 (10.0, 142)/300 98 (1.0, 14)/300
  9. If compression in one or more cylinders is low:
    1. Pour a small amount of engine oil into cylinders through the spark plug holes.
    2. Retest compression (steps 5 - 8).
      • If adding oil helps raise compression pressure, then the piston rings may be worn or damaged. If so, replace piston rings after checking piston. 
      • If the pressure stays low, a valve may be sticking or is seating improperly. Inspect and repair the valve and/or valve seat. Refer to  "CYLINDER HEAD ". If the valve and/or valve seat is damaged excessively, replace as necessary. 
      • If compression stays low in two or more cylinders that are next to each other: 
        • The cylinder head gasket may be leaking.
        • Both cylinders may have valve component damage. Inspect and repair as necessary.
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