Compression Pressure Inspection

WARNING: This page is about a different variant/trim than selected.

NOTE: If the 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.
Disconnect the ignition coil connectors (A).

Fig 1: Disconnecting Ignition Coil Connectors
Courtesy of HYUNDAI MOTOR AMERICA
Remove ignition coils (A).

Fig 2: Removing Ignition Coils
Courtesy of HYUNDAI MOTOR AMERICA
Remove spark plugs.
Using a 16mm plug wrench, remove the 4 spark plugs.
Check cylinder compression pressure.
1. Insert a compression gauge into the spark plug hole.
  
  Fig 3: Inserting Compression Gauge Into Spark Plug Hole
  Courtesy of HYUNDAI MOTOR AMERICA
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 200 RPM or more.
4. Repeat steps 1 through 3 for each cylinder.
  NOTE: This measurement must be done in as short a time as possible.
  
  Compression pressure:
  
  1078 kPa (11.0 kgf/cm² , 156 psi)/200 ~ 250 RPM
  
  Minimum pressure:
  
  931 kPa (9.5 kgf/cm² , 135 psi)
  
  Difference between each cylinder:
  
  100 kPa (1.0 kgf/cm² , 15 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 through 3 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.
Reinstall spark plugs.
Install ignition coils.
Connect the injector extension connector and ignition coil connectors.
Some DTC's may exist after the inspection test and may need to be manually cleared with GDS.