Fuel Supply System

Fuel Supply System

Fuel Pump Control
When the ignition is turned on, the ECM/PCM grounds the PGM-FI main relay which feeds current to the fuel pump for two seconds to pressurize the fuel system. With the engine running, the ECM/PCM grounds the PGM-FI main relay and feeds current to the fuel pump. When the engine is not running and the ignition is on, the ECM/PCM 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 injectors is cut off to improve fuel economy at speeds over 1,100 rpm.

Fuel cut-off action also occurs when engine speed exceeds 6,600 rpm, regardless of the position of the throttle valve, to protect the engine from over-revving. When the vehicle is stopped, the ECM/PCM cuts the fuel at engine speeds over 5,000 rpm.




PGM-FI Main Relay
The PGM-FI relay contains two separate relays. One is energized whenever the ignition is on which supplies battery voltage to the ECM/PCM, power to the injectors, and power for the second relay. The second relay is energized to supply power to the fuel pump for two seconds when the ignition is switched ON (II), and when the engine is running.