Engine Start-Up Mode

This is an OPEN LOOP mode. If vehicle is in park or neutral (automatic transaxles) or clutch pedal is depressed (manual transaxles) ignition switch energizes starter relay. The following actions occur when starter motor is engaged.

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

Once ASD and fuel pump relays have been energized, 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 PCM maintains ignition timing at 9° BTDC.