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DIAGNOSIS AND TESTING ENGINE DIAGNOSIS - INTRODUCTION Engine diagnosis is helpful in determining the causes of malfunctions not detected and remedied by These malfunctions may be classified as either mechanical (e.g., a strange noise), or performance Refer to the Engine Mechanical and the Engine Performance diagnostic charts, for possible causes For fuel system diagnosis, (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY - DIAGNOSIS AND TESTING). Additional tests and diagnostic procedures may be necessary for specific engine malfunctions that can- • Cylinder Compression Pressure Test • Cylinder Combustion Pressure Leakage Test • Engine Cylinder Head Gasket Failure Diagnosis • Intake Manifold Leakage Diagnosis • Hydraulic Lash Adjuster Noise Diagnosis • Engine Oil Leak Inspection DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE CONDITION POSSIBLE CAUSE CORRECTION ENGINE WILL NOT START 1. Weak battery. 1. Test battery. Charge or replace as 2. Corroded or loose battery 2. Clean and tighten battery 3. Faulty starter. 3. Test starting system. (Refer to 8 - 4. Faulty coil(s) or control unit. 4. Test and replace as needed. (Refer 5. Incorrect spark plug gap. 5. Set gap. (Refer to 8 - 6. Contamination in fuel system. 6. Clean system and replace fuel 7. Faulty fuel pump. 7. Test fuel pump and replace as 8. Incorrect engine timing. 8. Check for a skipped timing ENGINE STALLS OR IDLES ROUGH 1. Idle speed too low. 1. Test minimum air flow. (Refer to 2. Incorrect fuel mixture. 2. (Refer to Appropriate Diagnostic 3. Intake manifold leakage. 3. Inspect intake manifold, manifold 4. Faulty ignition coil(s). 4. Test and replace as necessary. CS ENGINE 3.8L 9 - 111 ENGINE 3.8L (Continued) |