Fuel delivery system - K Series 1.8 (Operation): Description and operation

Operation

The fuel pump is controlled by the Engine Control Module (ECM) via a fuel pump relay located in the engine compartment fusebox.

When the ignition is switched to position II, the ECM provides an earth path for the coil of the fuel pump relay on pin 68 of ECM connector C0913. The relay is energised for a short period to pressurise the fuel system. When the ECM senses that the engine has started by receipt of a valid signal from the CKP sensor, the ECM energises the fuel pump relay for as long as the engine is running.

The fuel shut-off switch is located in the power supply from the battery to the relay contacts. If the fuel shut-off switch is tripped the supply to the relay will be broken, preventing pump operation. The switch, located in the LH side of the engine compartment, below the E-box, breaks the circuit if a predetermined deceleration speed is exceeded, i.e. in the event of a collision. The fuel shut-off switch can be reset by depressing the rubber cap on the top of the switch.

WARNING: Ensure there are no fuel leaks and confirm the integrity of the fuel system before resetting the fuel shut-off switch.

The fuel pump, when running, outputs fuel at a constant pressure to the fuel rail. The pressure is controlled by the pressure regulator located in the pump. Excess fuel from the pressure regulator circuit is directed back to the pump swirl pot. The controlled pressure provides more fuel to the fuel rail than the maximum requirement of the engine, therefore a constant pressure is maintained in the rail under all operating conditions.