Engine Compression (5VZ-FE): 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 HIGH-TENSION CORDS WITH IGNITION COILS (See  ON-VEHICLE INSPECTION  ) 
3. REMOVE SPARK PLUGS 
4. CHECK CYLINDER COMPRESSION PRESSURE 
   1. Insert a compression gauge into the spark plug hole.
   2. Fully open the throttle.
   3. While cranking the engine, measure the compression pressure.

      HINT:

      Always use a fully charged battery to obtain engine speed of 250 RPM or more.

   4. Repeat steps  a through  c for each cylinder.
      Fig 1: Checking Compression Pressure

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE: This measurement must be done in as short a time as possible.

      Compression pressure: 

      1,200 kPa (12.2 kgf/cm ²  , 174 psi) or more 

      Minimum pressure: 1,000 kPa (10.2 kgf/cm ²  , 145 psi) 

      Difference between each cylinder: 

      100 kPa (1.0 kgf/cm ²  , 15 psi) or less 

   5. If the cylinder compression in 1 or more cylinders is low, pour small amount of engine oil into the cylinder through the spark plug hole and repeat steps  a through  c for cylinders with low compression.
      • If adding oil helps the compression, it is likely that the piston rings and/or cylinder bore are worn or damaged.
      • If pressure stays low, a valve may be sticking or seating is improper, or there may be leakage past the gasket.
5. REINSTALL SPARK PLUGS 

   Torque: 18 N.m (180 kgf.cm, 13 ft.lbf) 

6. REINSTALL HIGH-TENSION CORDS WITH IGNITION COILS (See  ON-VEHICLE INSPECTION  )