FixVault

Measurement Procedure

    Fig 1: Engine Compression Test Tool
    GM2308858Courtesy of GENERAL MOTORS COMPANY
  1. Install the suitable engine compression test tool to the spark plug hole.
  2. Start the engine (approximately 4 seconds).
  3. Compare the compression values.
  4. NOTE:

    Engine revs at least 300/min.

  5. Maximum pressure differential is 100 kPa (14.5 psi).
  6. Check compression for all cylinders.