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Home >> Hyundai >> 2020 >> Venue SEL >> Repair and Diagnosis >> Engine Mechanical >> Mechanical >> Engine Mechanical System - General Information >> Repair Procedures >> Compression Pressure Inspection

Compression Pressure Inspection

NOTE:
  • If the there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure.
  1. Start the engine and turn the coolant temperature to 80 - 95°C and stop.
  2. Remove the engine cover.

    (Refer to Engine and Transaxle Assembly - "ENGINE COVER ")

  3. Disconnect the injector connectors (A).
    G14693765Courtesy of HYUNDAI MOTOR AMERICA
  4. Remove the ignition coils.

    (Refer to Engine Electrical System - "IGNITION COIL ")

  5. Remove spark plugs.

    (Refer to Engine Electrical System - "SPARK PLUG ")

  6. Check the cylinder compression pressure.
    1. Insert a compression gauge into the spark plug hole.
      G14693766Courtesy of HYUNDAI MOTOR AMERICA
    2. Fully open the throttle valve.
    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:
      • If you need to check the compression pressure for more than three times, restart the engine to restore the lubrication condition to be normal and then check the compression pressure again.

      Compression pressure 

      Standard: 1225.83 kPa (12.5 kg/cm, 177.79 psi) (200-250 RPM)

      Minimum: 1078.73 kPa (11.0 kg/cm, 156.46 psi)

      Difference between each cylinder: 98 kPa (1.0 kg/cm, 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 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.
  7. Install the spark plugs.

    (Refer to Engine Electrical System - "SPARK PLUG ")

  8. Install the ignition coil.

    (Refer to Engine Electrical System - "IGNITION COIL ")

  9. Connect the injector connectors (A).
    G14693767Courtesy of HYUNDAI MOTOR AMERICA
  10. Some DTCs may exist after the inspection test and may need to be manually cleared with GDS.
  11. Install the engine cover.

(Refer to Engine and Transaxle Assembly - "ENGINE COVER ")

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