Engine Start-Up Mode

This is an OPEN LOOP mode. If the vehicle is in park or neutral (automatic transaxles) or the clutch pedal is depressed (manual transaxles) the ignition switch energizes the starter relay when the engine is not running. The following actions occur when the starter motor is engaged:

• If the PCM receives the camshaft position sensor and crankshaft position sensor signals, it energizes the fuel pump. If the PCM does not receive both signals within approximately one second, it will not energize the fuel pump. The PCM supplies voltage to the fuel pump, fuel injectors, ignition coil, (EGR solenoid and PCV heater if equipped) and heated oxygen sensors.
• The PCM energizes the injectors (on the 69 degree falling edge) for a calculated pulse width until it determines crankshaft position from the camshaft position sensor and crankshaft position sensor signals. The PCM determines crankshaft position within 1 engine revolution.
• After determining crankshaft position, the PCM begins energizing the injectors in sequence. It adjusts injector pulse width and controls injector synchronization by turning the individual ground paths to the injectors On and Off.
• When the engine idles within ±64 RPM of its target RPM, the PCM compares current MAP sensor value with the atmospheric pressure value received during the Ignition Switch On (zero RPM) mode.

Once the fuel pump relay has been energized, the PCM determines injector pulse width based on the following:

• MAP
• Engine RPM
• Battery voltage
• Engine coolant temperature
• Inlet/Intake air temperature (IAT)
• Throttle position
• The number of engine revolutions since cranking was initiated

During Start-up the PCM maintains ignition timing at 9 degrees BTDC.