Audi A3

since 1997 of release

Repair and car operation



Audi A3
+ Maintenance instruction
+ Current leaving and service
+ Engine
+ Systems of cooling, heating
- Power supply system and production of the fulfilled gases
   + Power supply system
   - System of injection of fuel
      General information and security measures
      Removal, installation and check of the fuel distributive highway and injectors
      Check and adjustment of number of turns of the single course/the moment of ignition/concentration WITH
   + System of injection of the diesel engine
   + System of production of the fulfilled gases
+ engine Electric equipment
+ Manual box of gear shifting
+ Automatic transmission and models with a full drive
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Elektroskhema







System of injection of fuel

General information and security measures

GENERAL INFORMATION

Arrangement of elements of a control system of the Simos engine. Engines of 1.6 l

1-socket
For the Hall sensor (black)
2-Hall sensor
Under the top cover of a gear belt
3-oxygen sensor, 50 N
Situation at AT: in a final collector
4-socket
For the oxygen sensor, from the bottom party of the car on the right
5-valve of switching of the inlet pipeline
6-Simos monitor
7-control unit butterfly valve
8-the sensor of temperature of cooling liquid
9-measuring instrument of weight of air
With the sensor of temperature of soaked-up air
10-weight accession at RKPP
11-ignition coils
With a step of target capacity
12-socket
For the detonation sensor
13-sensor of number of turns of the engine
14-socket
For the sensor of number of turns of the engine (black)
15-detonation sensor
16-injectors
17-regulator of pressure of fuel
18-adsorber
19-electromagnetic valve of an adsorber

Arrangement of elements of a control system of the Motronic engine. Engine of 1.8 l (125 h.p.)

1-the electromagnetic valve for an adsorber
2-socket
For the oxygen sensor (black)
3-the sensor of temperature of soaked-up air
4-control unit butterfly valve
5-Motronic monitor
6-valve of adjustment of a camshaft
7-measuring instrument of weight of air
8-the sensor of temperature of cooling liquid
9-regulator of pressure of fuel
10-injectors
11-ignition coils, target step
12-sensor of number of turns of the engine
13-sensor of a detonation 2
14-socket
For the sensor of a detonation 2.
15-sensor of a detonation 1
16-socket
For the sensor of number of turns of the engine.
17-socket
For the sensor of a detonation 1.
18-Hall sensor
Instruction: About 8/97 releases the adjustable pipe of an admission with the switching valve is in addition established.

The electronic control system of the engine regulates amount of fuel submitted to cylinders and operates ignition process. At petrol engines of the AUDI A3 car various control systems are applied.

The electronic control system of the engine provides the following possibilities:

– An exact dosage of fuel in any mode of operation that provides small fuel consumption at high capacity.
– Reduction of the content of harmful substances in the fulfilled gases thanks to exact dispensing of fuel and use of the catalytic converter.
– Self-diagnostics of a control system by the engine that provides possibility of fast troubleshooting. The control system of the engine has memory of malfunctions. If defect in use comes to light, it is brought in memory of the device. If in the engine there are malfunctions, there is a possibility to deduce on the printer the list of the malfunctions, allowing to reveal and eliminate defect independently.

The control unit the engine represents the microprocessor with high speed. It defines optimum time of injection and amount of injected fuel. Thus there is a coordination of operation of the control unit with other systems of the car, for example, to a control system of RKPP or blocking from stealing.

Elements of a control system of the engine keeps the high performance for a long time and practically does not demand service. Replacements at carrying out maintenance demand only the air filter and spark plugs. Serious works on adjustment and repair demand use of difficult diagnostic devices. Carrying out them is possible only in conditions HUNDRED.

Adjustment of number of turns of idling and concentration WITH within carrying out maintenance is not required.

Security measures at work with a control system of the engine / the petrol engine

The fuel system is under pressure! When opening system fuel emission is possible. Therefore the flowed-out fuel is necessary for wiping a rag. Pairs of gasoline are poisonous and is combustible. Use goggles. Watch good ventilation of a workplace. Have on call the fire extinguisher.

For an exception of a travmirovaniye of people and/or damage of system of injection and ignition it is necessary to observe the following:

– Do not concern and do not disconnect ignition wires at the working engine or at the included starter.
– Disconnect and attach pipelines of system of injection and an ignition wire, and also electric wires of devices of measurement only at the switched-off ignition.
– It is not necessary to work with electronic system of ignition to people with a warm stimulator.
– At check of a compression fuel injection is not allowed.

ATTENTION

At work with system of injection it is necessary to observe the general safety rules and purity.



Remarks on check of a control system by the engine

– For search of malfunctions, first of all, it is necessary to deduce indications from memory of malfunctions and to check on tightness vacuum accessions.
– For reliable functioning of all electric elements of system existence of tension is necessary not less than 11.5 Century.
– If after search of malfunctions, carrying out repair or check of details it is started only for short time, and then stops, the reason can be that the anticreeping system is blocked. For this purpose it is necessary to interrogate memory of malfunctions and if necessary to adjust a monitor.

Work of system of injection of the petrol engine

Fuel from a fuel tank is sucked in by an electric gasoline pump and moves via the fuel filter located on a floor of the car to injectors. The regulator of pressure supports constant pressure in fuel system.
Through electricly operated injectors fuel portsionno moves in the corresponding inlet pipe directly ahead of inlet valves of the engine. The control unit the engine operates duration of injection and by that amount of injected fuel.

The air which is sucked in in the engine, passes the air filter, arrives through a butterfly valve and soaking-up pipe to inlet valves.

The mass of soaked-up air defines amount of injected fuel. The mass of soaked-up air is measured by a special measuring instrument. In the case of a measuring instrument there is thin, electricly a heated-up sensitive plate–1–which is cooled with a stream of air passing through it. For maintenance of constant temperature of a sensitive plate the size of a current changes according to mass of sucked-in air. The size of a current specifies to the control unit degree of loading of the engine and by that regulates amount of injected fuel.

Arrangement of the film conductor 1 in a measuring instrument of weight of air


Information arriving from various sensors and team, arriving to executive bodies, provides optimum operation of the engine in various service conditions. If sensors fail, the control unit is switched to the emergency program to exclude damages of the engine and to provide possibility of further movement of the car. Failure of sensors not necessarily should affect operation of the engine negatively. However at the closest control of composition of the fulfilled gases it is necessary to consider indications of memory of malfunctions of a control system as the engine.

Sensors and executive mechanisms of engine management


The butterfly valve is located in the central control unit where information from various sensors is concentrated. The main objective of the control unit is stabilization of a mode of idling at all power setting and loading conditions. The switch of idling hands over to the control unit information on the provision of idling of a butterfly valve. The control unit via the electric motor opens or closes a butterfly valve, regulating, thus, number of turns of idling.

The sensor of temperature of cooling liquid and the sensor of temperature of soaked-up air hand over in the control unit information on the current value of temperatures on the basis of change of value of their electric resistance. At temperature increase resistance decreases.

– The system of ventilation of a fuel tank consists of an adsorber and the electromagnetic valve. In an adsorber pairs of gasoline which are forming in a tank owing to heating of fuel collect. At the working engine of pair of gasoline are sucked away from an adsorber and move in the engine.

The sensor of oxygen measures the content of oxygen in the fulfilled gases and transmits the corresponding signal in the control unit the engine.

The sensor of a detonation serves for definition of the optimum moment of ignition. At malfunctions of ignition supply of fuel to the corresponding cylinder stops.

Engines 1.8 of l/125 of h.p. with 8/97, engines of 1.6 l have the adjustable inlet pipeline which depending on number of turns of the engine changes parameters of a soaking-up path. For this purpose in the inlet pipeline the zaslonka with a pneumatic drive is established. The long pipeline at low number of turns thanks to resonant effect provides good filling of cylinders and by that a high torque. At high number of turns of the engine the inlet pipeline is shortened that provides more complete use of potential of engine capacity.

Engines 1.8 of l/125 of h.p.: For receiving optimum capacity and an engine torque in a wide range of turns there is a mechanism of regulation of the moment of opening and closing of inlet valves depending on number of turns. Usually time of opening and closing is defined by a camshaft configuration. For ensuring variativny adjustment of cams, camshafts of inlet and final valves are connected with each other by a chain. The hydraulic mechanism of adjustment, depending on engine turns, displaces a point of turn of a chain in a branch of connection of gear wheels of cam-shafts. Thanks to it phases of operation of inlet valves in relation to the final are displaced. For torque increase in a range from low to average turns the adjustment mechanism turns on, and the camshaft of inlet valves opens and closes valves earlier.

Checks of system of injection of fuel – general information


In system of injection of fuel it is independently possible to check only the main electric chains.

If normal operation of the engine is broken, first of all check a condition of electric conducting and sockets. Check a condition of a filtering element of the air filter, and also a condition and an interelectrode gap of spark plugs. Check passableness of hoses of ventilation of a case of the engine and adjustment of a cable of an accelerator. If the engine still works unstably, check a compression in engine cylinders.

If there is a suspicion for bad work of an injector, clean it.

If the engine still works unstably, check elements of system of ignition.

If malfunction is not eliminated yet, check integrity of fuses and a condition of electric sockets and electroconducting. On electric sockets there should not be melted-off contacts, moisture, traces of corrosion, dirt and other damages.

After carrying out independent check address on specialized station "AUDI" for diagnostics of system of injection of fuel on the special equipment.