Fuel Pump: Description and Operation
Fuel Pump ControlWhen the ignition switch is initially turned on, the ECM supplies ground to the PGM-FI main relay that supplies current to the fuel pump for two seconds to pressurize the fuel system.
When the engine is running, the ECM supplies ground to the PGM-FI main relay that supplies current to the fuel pump.
When the engine is not running and the ignition is on, the ECM cuts ground to the PGM-FI main relay which cuts current to the fuel pump.
Fuel Cut-off Control
During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy at speeds over 1,050 rpm.
Fuel cut-off action also takes place when engine speed exceeds 7,700 rpm, regardless of the position of the throttle valve, to protect the engine from over-revving. The ECM cuts the fuel at engine speeds over 6,500 rpm (A/T model: 5,500 rpm) when the vehicle is not moving.