Starting Mode
STARTING MODEWhen the key is first turned "ON," the control module turns "ON" the fuel pump relay for two seconds, and the fuel pump builds up pressure to the injectors unit. The control module checks the Engine Coolant Temperature (ECT) sensor, Intake Air Temperature (IAT) sensor, Throttle Position (TP) sensor, Manifold Absolute Pressure (MAP) sensor, and ignition signal, then determines the proper air/fuel ratio for starting. This ranges from 1.5:1 at -36°C (-33°F) to 14.6:1, at 94°C (201°F) running temperature.
The control module controls the amount of fuel delivered in the starting mode by changing how long the injector is turned "ON" and "OFF." This is done by "pulsing" the injector for very short times.