Symptom Diagnosis

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce diagnostic time, ensure BASIC DIAGNOSTIC PROCEDURES in the BASIC TESTING and DIAGNOSTIC TESTS in the TESTS W/CODES articles in the ENGINE PERFORMANCE Section were performed before diagnosing a symptom. Following are some symptoms available for diagnosis.

• Erratic Timing Advance
• Timing Not Affected By Vacuum
• Engine Does Not Operate Smoothly Or Misfires At High Speed
• Engine Fails To Start
• Engine Backfires, Fails To Start
• Engine Continues To Run With Key Off
• Engine Runs Only With Key In Start Position
• Excessive Fuel Consumption
• Intermittent Spark