Compression Pressure Inspection

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

Warm up engine until the normal operating temperature (80~95°C(176-203°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 7 times to measure compression pressure.
  NOTE: Always use a fully charged battery to obtain engine speed of 250 rpm or more.
4. Repeat step 1 though 3 for each cylinder.
  NOTE: This measurement must be done in as short a time as possible.
  
  Compression pressure:
  
  1, 029kPa (10.5kgf/cm² , 149psi) (250~400 rpm)
  
  Minimum pressure:
  
  882kPa (9.0kgf/cm² , 128psi)
  
  Difference between each cylinder:
  
  98kPa (1.0kg/cm² , 14psi) 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 step 1 through 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, a valve may be sticking or seating is improper, or there may be 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 ")