LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Nissan-Datsun >> 2002 >> Sentra SE-R, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 184 (Engine Mechanical) >> Measurement Of Compression Pressure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Measurement Of Compression Pressure

WARNING: This page is about a different car, the 2002 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
  1. Warm up engine.
  2. Turn ignition switch OFF.
  3. Release fuel pressure.

    Refer to RELIEVING FUEL PRESSURE .

  4. Remove engine cover and throttle wire.
  5. Remove air duct with air cleaner case.
  6. Remove harness connectors and harness brackets around ignition coils.
  7. Remove throttle body.
  8. Disconnect ignition coil with power transistor harness connectors, then remove ignition coils.
    Fig 1: Locating Ignition Coil Left Bank
    G02010473Courtesy of NISSAN MOTOR CO., U.S.A.
  9. Remove all spark plugs.
    • Clean area around plug with compressed air before removing the spark plug.
  10. Attach a compression tester to No. 1 cylinder.
  11. Depress accelerator pedal fully to keep throttle valve wide open.
  12. Crank engine and record highest gauge indication.
  13. Repeat the measurement on each cylinder as shown above.
    • Always use a fully-charged battery to obtain specified engine speed. 
      Fig 2: Locating Ignition Coil Right Bank
      G02010474Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 3: Attaching Compression Tester
      G02010475Courtesy of NISSAN MOTOR CO., U.S.A.
  14. If compression in one or more cylinder is low:
    1. Pour a small amount of engine oil into cylinders through spark plug holes.
    2. Retest compression.
      • If adding oil helps compression, piston rings may be worn or damaged. If so, replace piston rings after checking piston. 
      • If pressure stays low, a valve may be sticking or seating improperly. Inspect and repair valve and valve seat. (Refer to  VALVE   and  VALVE GUIDE   .) If valve or valve seat is damaged excessively, replace them. 
      • If compression stays low in two cylinders that are next to each other: 
        1. The cylinder head gasket may be leaking, or
        2. Both cylinders may have valve component damage. Inspect and repair as necessary.
  15. Install parts in reverse order of removal.
  16. Perform "Self-diagnosis Procedure" referring to CLEARING DIAGNOSTIC TROUBLE CODES if any DTC appears.
    Fig 4: Compression Value Chart
    G02010476Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 5: Identifying Compression Tester Rubber End Diameter
    G02010477Courtesy of NISSAN MOTOR CO., U.S.A.
scientia non olet · About LEMON Manuals