Starting Mode

When the ignition is first turned to the On position, the ECM turns On the fuel pump relay for two seconds, allowing the fuel pump to build pressure. The ECM also checks the Engine Coolant Temperature (ECT) sensor and Throttle Position (TP) sensor, to determine the proper air/fuel ratio for starting. This ranges from approximately 0.8:1 at -40°C (-40°F) to 14.6:1 at 104°C (220°F) engine coolant temperature.