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Home >> Jeep >> 2007 >> Commander Base, 4.7 P, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (3.7L Engine (Service Information)) >> Diagnosis And Testing >> Cylinder Compression Pressure Leakage

Cylinder Compression Pressure Leakage

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

The results of a cylinder compression pressure test can be utilized to diagnose several engine malfunctions.

Ensure the battery is completely charged and the engine starter motor is in good operating condition. Otherwise the indicated compression pressures may not be valid for diagnosis purposes.

  1. Clean the spark plug recesses with compressed air.
  2. Remove the spark plugs.
  3. Secure the throttle in the wide-open position.
  4. Disable the fuel system.
  5. Remove the Automatic Shutdown (ASD) relay. Refer to REMOVAL .
  6. Insert a compression pressure gauge and rotate the engine with the engine starter motor for three revolutions.
  7. Record the compression pressure on the 3rd revolution. Continue the test for the remaining cylinders.
  8. See SPECIFICATIONS  for the correct engine compression pressures.