Fuel Pump Control

When the ignition switch is turned to ON (II), the PCM grounds PGM-FI main relay 2 which feeds current to the fuel pump control module. The PCM sends a signal to the fuel pump control module to operate the fuel pump for 2 seconds to pressurize the fuel system. When the engine starts, the fuel pump speed is controlled in four levels by the fuel pump control module. The PCM selects the fuel pump speed based on calculating the injector activation time and the engine speed, and then sends an operation command signal to the fuel pump control module. This operation decreases fuel pump noise at low engine speed.