Elements of the Motronic control system in the engine compartment 1.8 l (AVJ, BFB)
- 1 - Solenoid valve 1 adsorber control
- 2 - Lambda probe of the preliminary catalytic converter, 55Nm
- 3 - Lambda probe of the additional catalytic converter, 55Nm
- 4 — the Combined valve of an inlet of secondary air
- 5 - Coolant temperature sensor
- 6 - Engine speed sensor
- 7 - Secondary air inlet valve
- 8 - Connector holder under the coolant expansion tank. To disconnect the plug, disconnect the expansion tank and tilt it to the side
- 9 - Connector holder. Disconnect the connector, pos. 8
- 10 - Drainage compartment (electronics box). Installation location of the engine control unit with integrated height sensor, as well as for the current relay of the injection system.
- 11 - Drainage compartment (electronics box) with secondary air pump relay
- 12 - Boost pressure sensor. At the top of the intercooler
- 13 - Throttle control unit
- 14 - Intake air temperature sensor
- 15 - Turbocharger circulation valve. Located under the intake manifold
- 16 - Knock sensor 1
- 17 - Knock sensor 2
- 18 - Hall sensor
- 19 - Injector
- 20 - Ignition coil
- 21 - Solenoid valve boost control
- 22 - Air mass meter
- 23 - Secondary air pump motor
Fuel distribution line and injectors. Engine 1.8 l AVJ/BFB
- 31 - Screw, 10nm
- 32 - Protective cover
- 33 - Locking bracket. Observe the correct position on the injector and fuel distribution line
- 34 - Inlet pipeline with throttle control unit and intake air temperature sensor
- 35 - Insert for the injector, 3Nm. To be screwed on threadlocker D000600A2
- 36 - O-ring. Be sure to replace. Lubricate with clean engine oil before installation.
- 37 - Injector
- 38 - O-ring. Be sure to replace Lubricate with clean engine oil before installation.
- 39 - Fuel supply pipeline, 25Nm
- 40 - Fuel distribution line
- 41 - Connector
Elements of the control system in the engine compartment V6
- 1 - EVAP sensor
- 2 - EVAP purge valve
- 3 - Fuel pressure regulator
- 4 - ECT sensor
- 5 - Heated lambda probe
- 6 - CKP sensor
- 7 - Knock sensor 2
- 8 - crankshaft speed sensor
- 9 - Ignition coils
- 10 - Injector
- 11 - Knock sensor 1
- 12 - IAC valve
- 13 — the Switching valve of an inlet air duct
- 14 — TPS
- 15 - EGR temperature sensor
- 16 - E / m EGR vacuum control valve
- 17 — PCM
- 18 - CMP sensor
- 19 - Heated lambda probe
- 20 - MAF sensor
- 21 - Output stage of the ignition coil
Elements of the control system in the engine compartment model S4
- 1 - Lambda probe wiring connector 1 behind the catalytic converter
- 2 - Lambda probe wiring connector 2 behind the catalytic converter
- 3 - Wiring connector heated lambda probe in block 1
- 4 - Connector wiring knock sensor in block 1
- 5 - ECT sensor
- 6 - Bypass control valve of the exhaust system
- 7 - EVAP purge valve
- 8 - Temperature sensor No. 1 at the outlet
- 9 - E / m valve additional air inlet
- 10 — E/motor of the pump of an additional air inlet
- 11 - Temperature sensor No. 2 at the outlet
- 12 - Turbocharger circulation valve
- 13 - Air pressure regulator
- 14 - Sensor CMP unit 2
- 15 — The relay of the pump of an additional air intake
- 16 — ECM
- 17 - Wiring connector crankshaft speed sensor
- 18 - Connector electrical wiring knock sensor in block 2
- 19 - Wiring connector heated lambda probe in block 2
- 20 - E / m camshaft adjustment valve in block 2
- 21 - Throttle valve control module
- 22 - Charge air pressure sensor
- 23 - Sensor CMP block 1
- 24 - The output stage of the ignition coil in block 2
- 25 - The output stage of the ignition coil in block 1
- 26 - E / m camshaft adjustment valve in block 1
- 27 - Heated lambda probe wiring connector in block 2
- 28 - Knock sensor No. 1
- 29 - Knock sensor No. 2
- 30 - VSS sensor, in the transmission
- 31 - Heated lambda probe in block 2
- 32 - Ignition coils block 2
- 33 - Block 2 injectors
- 34 - IAT sensor
- 35 - IAT sensor wiring connector
- 36 - Block 1 injectors
- 37 - Ignition coils block 1
- 38 - MAF sensor
Fuel is drawn from the fuel tank by the electric fuel pump and fed through the fuel filter to the fuel distribution line. The pressure regulator maintains the pressure in the fuel system equal to 3.5, 4.0 or 6.0 atm., depending on the engine.
Through electrically controlled injectors, fuel is injected in pulses into the intake manifold located directly in front of the engine intake valves. The engine control unit sequentially controls the injectors in accordance with the ignition order, regulates the injection time and, thus, the amount of injected fuel.
The air necessary for the formation of the fuel mixture is sucked in by the engine through the air filter and enters through the throttle valve and intake pipe to the intake valves. The amount of air intake is controlled by a throttle valve, which is moved by a stepper motor controlled by the engine control unit. In turbocharged engines, the intake air is compressed by a turbocharger driven by the exhaust gases of the exhaust system. The compressed air is then cooled in the charge air cooler and enters the engine to form the fuel mixture.
The intake air volume is determined by the air quantity meter. The meter is located in the intake air duct. In the meter housing there is a thin, electrically heated sensor plate, cooled by the passing flow of intake air. The electric current heating the plate is regulated by the control system in such a way as to keep the temperature of the plate constant. If, for example, the amount of intake air increases, the temperature of the heated plate starts to decrease. At the same time, the magnitude of the electric current immediately increases in order to keep the temperature of the plate unchanged. Fluctuations in the electric current of the plate indicate to the engine control unit its load condition, which allows it to correctly determine the amount of fuel injected.
The control unit determines the optimal ignition timing, injection timing and the amount of injected fuel. In this case, the operation of the control unit is coordinated with other vehicle systems, for example, with the control of the gearbox or the anti-theft system.
Information from other sensors and control voltages supplied to the executive bodies ensure optimal engine operation in any situation. If some sensors fail, the control unit switches to the emergency program mode in order to exclude possible damage to the engine and ensure the further movement of the car. In this case, the engine runs unevenly and tends to stop when the gas is increased.
Sensors and actuators of the injection system
crankshaft position sensor screwed into the cylinder block at the flywheel. It transmits to the control unit information about the engine speed and the TDC position of the piston of the first cylinder.
Camshaft position sensor located at the end of the cylinder head cover. Together with the crankshaft position sensor, it transmits to the control unit information about the TDC of the piston of the first cylinder. It serves to synchronize the ignition timing and ignition sequence.
Throttle Potentiometer located in the throttle actuator and informs the control unit about the current throttle position angle. The second potentiometer informs the control unit about the base value and generates a spare signal when the throttle potentiometer fails.
Accelerator pedal sensor located in the area where the driver's feet are located directly on the pedal axis. It informs the control unit about the position of the pedal. For reasons of reliability, a redundant signal is received from the pedal sensor, as well as from the throttle potentiometer.
Coolant temperature sensors located in the thermostat housing. It is an NTC resistor whose resistance decreases with increasing temperature.
intake air temperature sensor is also an NTC resistor.
The fuel tank ventilation system consists of adsorber and solenoid valve. The adsorber accumulates fuel vapors formed as a result of fuel heating. When the engine is running, the vapors are sucked out of the adsorber and fed into the combustion chambers of the engine.
lambda probes (oxygen sensors) they measure the oxygen content in the exhaust gases before and after the catalytic converter and transmit the corresponding signals to the engine control unit. One lambda probe is located before and the other after the catalytic converter.
Knock sensor screwed into the cylinder block. It prevents the occurrence of dangerous impact combustion of the fuel mixture. Thanks to this, the ignition timing can be kept at the detonation limit, which ensures efficient use of the energy of combustion of the fuel and thus reduces fuel consumption.
Switchable intake manifold (engine 2.0 l ALT)
The required power and torque performance is achieved with a two-stage switchable intake manifold. In this case, the switching of the pipeline from short to long takes place in the speed range of 2.000 - 3.700 rpm. The switch roller, which separates the individual inlet ducts by means of elastic sealing rings and sealing strips, opens the intake tract. Switching between torque and power positions is electro-pneumatic (depending on load, speed and temperature) (refer to the illustrations below).
Inlet piping in torque optimization position
- 1 - Switching roller
- 2 - Vacuum accumulator. On the 2.0l FSI AWA engine is located inside the intake manifold
Inlet piping in power optimization position
Accelerator servo
Instead of a conventional gas drive, there is a pedal position sensor on the gas pedal (illustration below), which transmits information about the position of the pedal to the engine control unit. Based on the information received, the control unit controls the position of the throttle valve via the electric motor.
Accelerator pedal sensor
- 1 - Gas pedal
- 2 - Resistive track
- 3 - Sensor 1+2
The position sensor housing contains two contact potentiometers, which are mounted on a common shaft. With each change in the position of the pedal, the resistance of the potentiometers and the voltages transmitted to the engine control unit change.
If any sensor fails, the gas drive malfunction lamp lights up and damage is recorded in the control unit's fault memory. If both sensors fail, the engine runs at an increased speed and no longer responds to the gas pedal.
Throttle Actuator Unit (refer to the illustration below) includes an electric motor, two potentiometers and a gear system with a return spring. It controls the throttle position. The task of the control unit is to stabilize the idle speed, regardless of the connection of additional consumers, such as power steering or air conditioning compressor.
Throttle Actuator Unit
- 1 - Throttle body
- 2 - Throttle actuator
- 3 - Housing cover with built-in electronics
- 4 - Throttle valve
- 5 - Throttle valve potentiometer (throttle actuator angle sensor 1+2)
- 6 - Gear wheel with spring return
The throttle potentiometer is located at the throttle shaft and provides the control unit with current information about the angle of the throttle. The second potentiometer informs the control unit about the reference value and provides a backup signal in case of failure of the potentiometer.
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