Fuel Supply System

Fuel Supply System

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 1,050 rpm.
Fuel cut-off action also occurs when engine speed exceeds 9,000 rpm, regardless of the position of the throttle valve, to protect the engine from over-revving.

Fuel Pump Control
When the ignition is turned ON (II), the ECM 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 ECM grounds the PGM-FI main relay and feeds current to the fuel pump. When the engine is not running and the ignition is ON (II), the ECM 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 which supplies battery voltage to the ECM, power to the 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 switch is ON (II), and when the engine is running.