Starting Mode
When the ignition is first turned ON (before engaging the starter), the
PCM energizes the
fuel pump relay for a calibrated time (approximately
2 seconds) allowing the
fuel pump to build up pressure. The PCM also checks the Engine Coolant Temperature
(ECT) and Throttle Position
(TP) sensors to determine the proper air/fuel ratio for starting. The air/fuel ratio ranges from approximately
0.8:1 at
-40°C (-40°F) to
16.8:1 at
110°C (230°F) engine coolant temperature. The PCM controls the amount of fuel delivered by changing how long the injectors are energized. This is done by pulsing the injectors for very short times.