Diagnosis And Testing: Introduction

Engine diagnosis is helpful in determining the causes of malfunctions not detected and remedied by routine maintenance.

These malfunctions may be classified as either performance (e.g, engine idles rough and stalls) or mechanical (e.g, a strange noise).

Refer to PERFORMANCE  and MECHANICAL  for possible causes and corrections of malfunctions.

Additional tests and diagnostic procedures may be necessary for specific engine malfunctions that can not be isolated with the Service Diagnosis charts. Information concerning additional tests and diagnosis is provided within the following diagnosis:

1. Cylinder Compression Pressure Test. See CYLINDER COMPRESSION PRESSURE .
2. Cylinder Combustion Pressure Leakage Test. See CYLINDER COMBUSTION PRESSURE LEAKAGE .
3. Engine Cylinder Head Gasket Failure Diagnosis. See CYLINDER HEAD GASKET  for left cylinder head or CYLINDER HEAD GASKET for right cylinder head.
4. Intake Manifold Leakage Diagnosis. See INTAKE MANIFOLD LEAKAGE .