Fuel Supply System

Fuel Supply System

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 1,100 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 stopping, the PCM cuts the fuel at engine speed over 5,000 rpm.

Fuel Pump Control

When the ignition is turned on, the PCM grounds the PGM-FI main relay which feeds current to the fuel pump for 2 seconds to pressurize the fuel system. With the engine running, the 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 PCM cuts ground to the PGM-FI main relay which cuts current to the fuel pump.

PGM-FI Main Relay

The PGM-FI relay contains two separate relays. One is energized whenever the ignition is on. It supplies battery voltage to the PCM, power to the fuel injectors, and power for the second relay. The second relay is energized to supply power to the fuel pump for 2 seconds when the ignition is switched ON (II), and when the engine is running.