General information
The fuel system consists of a centrally mounted fuel tank, a mechanical fuel pump (only for later models), fuel filter with water separator, high-pressure fuel pump, injectors and other components. Turbocharging is installed on some engines, both those with a catalytic converter and those with an exhaust gas recirculation (EGR) system.
Fuel is drawn from the fuel tank by a high-pressure fuel pump, or a mechanical fuel pump on later models. Before entering the fuel pump, the fuel passes through a fuel filter, where it is cleaned of contaminants and water. Excess fuel lubricates the moving components of the pump and is then returned to the tank. The solenoid valve stops the fuel supply to the fuel pump plunger when the ignition is turned off.
The high pressure fuel pump is driven by a toothed belt from the crankshaft.
The high pressure required to force fuel into the compressed air in the combustion chambers is achieved by the action of a single piston (on Bosch pumps), or two oppositely directed pistons (on Lucas/CAV pumps).
Fuel passes through a plunger with a drilled hole that aligns with holes leading to tubes that deliver fuel to the injectors.
Fuel dosage is controlled by a centrifugal regulator, which responds to the position of the gas pedal and the engine speed. The regulator is linked to a metering valve that increases or decreases the amount of fuel injected with each pump stroke. On turbocharged engines, a separate device also increases the fuel delivery as pressure increases.
The basic injection advance is set when the pump is installed. When the engine is running, it changes automatically according to the engine speed using a mechanism that rotates the cam disc or ring. On engines with the Lucas EPIC control system (see below), the high-pressure fuel pump is electronically controlled. The precise dosage of fuel is regulated by an electronic control device.
Four fuel injectors spray a homogeneous aerosol of fuel into the cylinders. The injectors are adjusted to open and close at critical pressures, ensuring efficient and uniform combustion. Each injector needle is lubricated with fuel that collects in the spring compartment and is directed to the fuel pump drain hose through the drain pipe.
Depending on the model, Bosch or Lucas/CAV fuel system components may be installed. Components from Lucas/CAV may be marked "CAV", "Rota-Diesel" or "Con-Diesel". depending on the date and place of manufacture. With the exception of the fuel filter, replacement components should be the same brand as those originally installed.
On some models, the idle speed increases in accordance with the readings of the thermostatic sensor of the cooling system when the engine is cold.
On 1992 and later models, turbocharged engines are equipped with the Lucas EPIC electronic fuel injection system. Read more about this system in section 26.
Following the fuel injection system maintenance instructions will ensure its long and trouble-free operation. The condition of the fuel pump significantly affects the duration of normal engine operation. The main cause of damage to the fuel pump and injectors is dirt or water in the fuel.
Servicing the fuel pump and injectors is very difficult at home, and any removal or adjustment described in this Chapter should be performed by a Ford dealer or fuel system specialist.
Precautionary measures
Warning: Care must be taken when working with fuel system components, especially fuel injectors. Before performing any work on the fuel system, refer to the "Safety First!" section at the beginning of this manual and the warnings at the beginning of the relevant sections.