Contents: Throttle body ⬇ Injectors and fuel rail ⬇ Fuel pressure regulator ⬇ Throttle Position Module ⬇ Intake air temperature/pressure…⬇ Coolant temperature sensor ⬇ Oxygen sensor (λ-probe) ⬇ Electronic Control Unit (ECU) ⬇ Fuel Pump Relays and Fuses ⬇
Schematic diagram of the components of the MPFI Magneti-Marelli 1AV system
1 - Temperature and air flow sensor; 2 - Crankshaft speed and position sensor; 3 - λ-probe; 4 - Knock sensor; 5 - Coolant temperature sensor; 6 - TPS, stepper motor and limit switch; 7 - Additional signal; 8 - ECU (microprocessor 1AV MPIS 192); 9 - Immobilizer ECU; 10 - Diagnostic connector; 11 - Ignition coil; 12 - Fuel injectors; 13 - Fuel pump relay; 14 - E/M carbon adsorber purge valve; 15 - Stepper motor
Note: See the warnings given in Section General information and precautions.
The connection diagram of the MPFI system components is shown in the illustration.
Throttle body
Removal
1. Remove the throttle body and air cleaner upper covers (see section Removal and installation the air cleaner assembly).
2. Disconnect the accelerator cable from the throttle position control lever (see section Removal, installation and adjusting the accelerator cable).
3. Disconnect the negative cable from the battery.
4. Disconnect the throttle position module wiring connector.
5. Disconnect the hose from the carbon canister from the front of the throttle body.
6. Unscrew the four through bolts and remove the throttle body from the intake manifold. Also remove the sealing washer - it must be replaced during assembly.
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Installation
Installation is carried out in reverse order. Please note the following points:
- a) Don't forget to replace the sealing washer;
- b) The throttle body through bolts must be tightened to the required torque;
- c) Check the quality of all hose and electrical connections;
- d) Do not forget to adjust the tension of the accelerator cable (see section Removal, installation and adjusting the accelerator cable).
Injectors and fuel rail
Note: If you suspect that your injectors are faulty, do not immediately begin to remove them. First, try to clean the injectors by adding a special additive to the fuel (ask at auto chemical stores).
Removal
1. Release the pressure in the fuel system (see section Relief of residual pressure in the fuel system).
2. Disconnect the negative cable from the battery.
3. Remove the upper throttle body cover (see section Removal and installation the air cleaner assembly).
4. After marking, disconnect the electrical wiring from the injection injectors.
5. Release the harness from the clips on the top of the fuel line and move it to the side.
6. Disconnect the vacuum hose from the fitting at the bottom of the fuel pressure regulator.
7. Disconnect the fuel supply and return hoses from the end of the fuel line. Try to remember the installation position of the hoses (check them for factory flow direction markings).
8. Unscrew the two mounting bolts and carefully remove the fuel line together with the injection injectors from the intake manifold. Make sure that when removing the injectors from their mounting seats in the line, the lower sealing rings remain in their regular places.
9. The injectors can be removed from the line individually by removing the metal retainers. Remove the upper injector sealing rings.
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10. If necessary, remove the fuel pressure regulator.
11. Using a universal tester, measure the electrical resistance of each injector. Compare the measurement results with the requirements Specifications.
Installation
Installation is carried out in reverse order. Please note the following points:
- a) Do not forget to check the condition of the injector sealing rings. Defective rings must be replaced;
- b) Check that the metal fastening clips of the injectors are securely seated;
- c) Ensure that the fuel supply and return hoses are correctly connected to the line;
- d) Check the quality of all hose and electrical connections;
- e) Before operating the vehicle, check the fuel system for leaks.
Fuel pressure regulator
Removal
1. Release the pressure in the fuel system (see section Relief of residual pressure in the fuel system).
2. Disconnect the negative cable from the battery.
3. Remove the upper throttle body cover (see section Removal and installation the air cleaner assembly).
4. Disconnect the vacuum hose from the fitting at the bottom of the pressure regulator.
5. Loosen the clamp and disconnect the fuel supply hose from the line. This will cause most of the fuel in the line to spill out - prepare a small drain container and place a rag under the regulator assembly.
6. Remove the fastening clamp from the top of the regulator housing secured to the end of the fuel line. Remove the regulator with the sealing rings.
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Installation
Installation is carried out in reverse order. Please note the following points:
- a) Worn sealing rings must be replaced without fail;
- b) Check that the retainer is securely seated;
- c) Check that the vacuum hose is securely connected.
Throttle Position Module
The module is built into the throttle body and cannot be replaced individually. If problems arise, contact the car service specialists for help.
Intake air temperature/pressure sensor
Removal
1. The sensor is installed on the right side of the intake manifold.
2. Disconnect the negative cable from the battery.
3. Remove the upper throttle body cover (see section Removal and installation the air cleaner assembly).
4. Disconnect the electrical wiring from the sensor.
5. Remove the two mounting screws and remove the sensor from its seat in the pipeline.
Installation
Installation is carried out in the reverse order. Make sure that the fasteners are tightened securely.
Coolant temperature sensor
The fuel injection system coolant temperature sensor is part of the coolant temperature sensor (CTS).
Oxygen sensor (λ-probe)
See Section Removal and installation the λ-probe.
Electronic Control Unit (ECU)
The ECU is located at the rear on the left bulkhead of the engine compartment. The unit is protected by a special code and should not be removed without prior consultation with representatives of the Skoda branded service center. Unauthorized disconnection of the multi-pin connector may lead to malfunction of the ECU.
Fuel Pump Relays and Fuses
1. The fuel pump relay and injection system fuses are located in the mounting block installed in the vehicle interior (see Chapter On-board electrical equipment).
2. The pump relay is located in the fifth position in the row of relays on the working panel of the mounting block. The electric circuit of the pump power supply circuit is protected by fuse No.4.
3. The relay is removed from its socket by simply pulling it out. The installation of the relay is unambiguous due to the asymmetric shape of the socket.
4. The fuse is removed in the same way as all other fuses (see Chapter On-board electrical equipment).
5. It should be noted that removing the main fuse of the injection system (No. 1) leads to erasing the adaptation data from the ECU memory, just as it happens when disconnecting the battery. Resetting the operating parameters takes some time, which can lead to a violation of the stability of the idle speed during the first few minutes after the first start of the engine.