Fuel shut-off solenoid (Engine management system - EDC)

Fuel shut-off solenoid

The fuel shut-off solenoid is located in the high pressure section of the injection pump. When the ignition is switched on the engine control module sends a signal to the solenoid. The solenoid energises opening a valve allowing fuel to flow.

When the ignition is switched off, or in the event of a serious engine problem, the control unit will remove the supply to the solenoid, closing the valve and shutting off the fuel supply to the injectors.

EXHAUST GAS RECIRCULATION (EGR)

During certain running conditions the EGR system directs exhaust gases into the intake manifold to be used in the combustion process. The principal effect of this is to reduce combustion temperatures, which in turn reduces Oxides of Nitrogen (NO_x) emissions.

The EGR diaphragm valve is vacuum operated through a solenoid valve, mounted to the rear of the LH valance. When the ECM determines that exhaust gas recirculation should take place, the solenoid valve is modulated and vacuum, supplied by the brake servo vacuum pump, opens the EGR valve. Exhaust gases are then fed through a pipe into the exhaust manifold.

An air flow meter, mounted in the air intake pipe below the air cleaner, senses the volume of air entering the engine. Using the principle that an increase in EGR will lead to a decrease in the intake air flow, the air flow meter is used by the ECM to monitor the amount of exhaust gases being recirculated. This feedback signal allows the ECM to accurately control the volume of exhaust gases being recirculated.