Timing Advance System

ECM controls ignition timing advance based upon sensor input signals that reflect ignition timing needs. If timing problems are experienced, inspect input signals for proper operation:

• Battery Voltage
• Closed Throttle Position Switch
• Crankshaft Position Sensor
• Engine (Coolant) Temperature
• Ignition (START) Signal
• Mass Airflow Sensor
• Park/Neutral (Inhibitor) Switch. (Signal received from transmission control unit).
• Power Steering Pressure Switch
• Throttle Position Sensor
• Vehicle Speed Sensor

To check input signals, see ENGINE SENSORS & SWITCHES or ECM pin voltage charts in PIN VOLTAGE CHARTS article in the ENGINE PERFORMANCE Section.