Engine Mechanical: Compression: Inspection

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

Warm up and stop engine .
Allow the engine to warm up to normal operating temperature.
Remove ignition coils (See REMOVAL & INSTALLATION (RAV4) ) .
Remove spark plugs .
Inspect 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.
  NOTE: 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: Displaying Compression Gauge
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  NOTE: This measurement must be done in as short a time as possible.
  1. Compression pressure: 1,270 kPa (13.0 kgf/cm ² , 184 psi)
  2. Minimum pressure: 1,000 kPa (10.2 kgf/cm ² , 145 psi)
  3. Difference between each cylinder: 100 kPa (1.0 kgf/cm ² , 15 psi) or less
5. If the cylinder compression in one more cylinders is low, pour a 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 through the gasket.
Reinstall spark plugs .
Reinstall ignition coils (See REMOVAL & INSTALLATION (RAV4) ) .