Engine Mechanical: Compression: Inspection

HINT:

If there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure.

1. WARM UP AND STOP ENGINE 

   Allow the engine to warm up to normal operating temperature.

2. REMOVE ENGINE COVER 

   Remove the 4 nuts and engine cover.

3. DISCONNECT IGNITION COILS AND HIGH-TENSION CORD SET ASSEMBLY (See  REMOVAL  ) 
4. REMOVE SPARK PLUGS 
5. DISCONNECT INJECTOR CONNECTORS 
6. CHECK CYLINDER COMPRESSION 
   1. Insert a compression tester into the spark plug hole.
      Fig 1: Inserting Compression Tester Into Spark Plug Holes

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. While cranking the engine, measure the compression pressure.

      HINT:

      Always use a fully charged battery to obtain engine revolutions of 250 rpm or more.

   3. Repeat steps  a through  b for each cylinder.
      NOTE: This measurement must be done in as short a time as possible.
      1. Compression: 1,324 kPa (13.5 kgf/cm ²  , 192 psi) or more 
      2. Minimum pressure: 1,079 kPa (11.0 kgf/cm ²  , 156 psi) 
      3. Difference between each cylinder: 98 kPa (1.0 kgf/cm ²  , 14 psi) or less 
   4. If the cylinder compression in 1 or more cylinders is low, pour a small amount of engine oil into the cylinder through the spark plug hole and repeat steps (a) through (b) for the cylinder with low compression.
      • If adding oil helps the compression, it is likely that the piston rings and/or cylinder bore are probably worn or damaged.
      • If pressure stays low, a valve may be sticking or seating improper, or there may be leakage past the gasket.
7. RECONNECT INJECTOR CONNECTORS 

   HINT:

   The Nos. 1, 3, 5 injector connectors and dark gray, and the Nos. 2, 4, 6 injector connectors are brown.

8. REINSTALL SPARK PLUGS 
9. RECONNECT IGNITION COILS AND HIGH-TENSION CORD SET ASSEMBLY (See  INSTALLATION  ) 
10. INSTALL ENGINE COVER 

    Install the engine cover with the 4 nuts.