Compression Pressure Inspection

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

Warm up the engine to the normal operating temperature [80 to -95°C (176 to -203°F)].
Remove the surge tank.
(Refer to Intake And Exhaust System - "SURGE TANK ")
Remove the ignition coils.
(Refer to Engine Electrical System - "IGNITION COIL ")
Remove the spark plugs.
(Refer to Engine Electrical System - "SPARK PLUG ")
Check cylinder compression pressure.
1. Insert a compression gauge into the spark plug hole.
2. Fully open the throttle.
3. Crank the engine over 10 times to measure compression pressure.
  NOTE: Always use a fully charged battery to obtain engine speed of 250 RPM or more.
4. Repeat steps 1 to 3 for each cylinder.
  NOTE: This measurement should be taken as promptly as possible.
  
  Compression pressure :
  
  1, 373 kPa (14.0 kgf/cm2, 199 psi) (250 - 400 RPM)
  
  Minimum pressure :
  
  1226 kPa (12.5 kgf/crrf, 178 psi)
  
  Difference between each cylinder :
  
  98 kPa (1.0 kg/cm2, 14 psi) or less
5. 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 1 to 3 for cylinders with low compression.
  1. If adding oil helps the compression, it is likely that the piston rings and/or cylinder bore are worn or damaged.
  2. If pressure stays low, there may be a sticking valve, an improper seating or leakage past the gasket.
Reinstall the spark plugs.
(Refer to Engine Electrical System - "SPARK PLUG ")
Install the ignition coils and ignition connectors. (Refer to Engine Electrical System - "IGNITION COIL ")
Install the surge tank.
(Refer to Intake And Exhaust System - "SURGE TANK ")