11.2. General information

The electronic control system of the BOSCH HFM engine operates system of injection of fuel and ignition.

The electronic control system of the engine consists of the fuel tank, the electric fuel pump, the fuel filter giving and returnable fuel hoses, the case of a throttle, the fuel highway, the fuel pressure regulator, four electronically the operated fuel nozzles and the electronic control device (ECU) together with sensors, executive mechanisms and electric wires.

The fuel tank on the Sedan and Coupet models is installed vertically behind a back of a back seat. On the Station wagon models the fuel tank is installed horizontally under a trunk floor. The fuel level sensor is fixed on the top part of the fuel tank and can be replaced without removal of the fuel tank.

The electric fuel pump with the circulating camera is installed under the bottom in a back part of the car. The engine of the fuel pump is constantly cooled with the fuel passing through it. The fuel pump has the unidirectional valve which, blocking fuel system, supports in it pressure even after switching off of the fuel pump. The valve also isolates the fuel tank from other part of fuel system. The pump also contains the safety valve of pressure which limits pressure in fuel system.

The fuel pump gives fuel via the fuel filter to the fuel highway under pressure exceeding pressure in fuel system. The regulator of pressure supports the constant required pressure in fuel system and returns excess fuel in the fuel tank on a returnable fuel-supply line. This constant circulation of fuel reduces temperature of fuel and a predotvr shchat fuel evaporation.

Fuel nozzles are an electromagician the nitny valves opened and closed by the electronic control device (ECU) which defines time of opening and duration of injection of fuel depending on turns of a bent shaft of the engine, the provision of a butterfly valve, size of the arriving mass of air, temperature of the air coming to the engine, temperature of cooling liquid and oxygen in exhaust gases on the basis of information obtained from the sensors installed on the engine and around it.

Air comes to the engine via the air filter with the replaceable filtering element. Temperature of the air coming to the engine is regulated by the vacuum valve installed in the air filter. The vacuum valve mixes the cold air coming to the engine with the air which is warmed up by a final collector. This valve unlike the measuring instrument of a stream of air of bladed type is sensitive to air density. It means that when the car is operated at big heights, depression of air without the need for use of separate barometric measurement of pressure of air is automatically considered.

Management of turns of idling is made by the control unit of turns of idling which is installed sideways throttle cases, and system of ignition which regulates idling turns, changing an ignition advancing corner.

Content of oxygen in exhaust gases is constantly controlled by the ECU block on the basis of signals the Lambda sensor which is installed on a reception exhaust pipe. On the basis of information the Lambda sensor the ECU block defines the moment and duration of injection of fuel to support an optimum ratio of fuel mix. Also need of manual adjustment of contents WITH in exhaust gases disappears. Besides, for reduction of emission of harmful substances in the atmosphere, some models are equipped with catalytic converter.

On some models the ECU block also operates operation of the activated coal filter.

Detection of malfunctions on an electronic control system of the HFM engine is possible only with use of the special diagnostic equipment.


The fuel system is under constant pressure, even after switching off of the engine therefore when carrying out any works on fuel system it is necessary to take off pressure.

For prevention of a possibility of casual short circuits of an electric chain and damage of electronic components of system of injection of fuel always remove a weight wire from the accumulator.


Gasoline extremely fire - is also explosive therefore it is necessary to show care during the work on any part of fuel system.

Works on fuel system need to be performed in well aired room for what it is possible to open all windows and doors for draft creation.

During the work on fuel system do not use naked flame, electric welding and tools during the work with which sparks can be formed. Check that in close proximity to a workplace there is a charged fire extinguisher.

For protection of eyes against hit of fuel in them use points. At hit of fuel on skin wash out this place a plentiful amount of water.

Capacity in which there was a fuel contains vapors of fuel and is potentially explosive.

During the work with fuel system observe purity as the dirt which got to canals of fuel system can block them that will break normal operation of the engine.