Magneti-Marelli 1AV MPFI System Component Diagram
1 - Temperature and air flow sensor; 2 - Speed sensor and position of the crankshaft; 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 - injection injectors; 13 - Fuel pump relay; 14 - E / m purge valve of the coal adsorber; 15 - Stepper motor
Note. See the warnings in Section General information and precautions.
The connection diagram of the MPFI system components is shown in the illustration.
Throttle body
Removing
1. Remove the upper covers of the throttle body and air cleaner (see Section Removing and installing the air cleaner assembly).
2. Disconnect the throttle cable from the throttle position control lever (see Section Removing, installing and adjusting the accelerator cable).
3. Disconnect the negative cable from the battery.
4. Disconnect the throttle position module harness connector.
5. Disconnect the hose coming from the carbon canister from the front of the throttle body.
6. Turn out four through bolts and remove the case of a throttle from the inlet pipeline. Also remove the sealing washer - during assembly it must be replaced without fail.
Installation
Installation is in the reverse order. Pay attention to the following points:
- a) Don't forget to replace the sealing washer;
- b) The through bolts of the throttle body must be tightened to the required torque;
- c) Monitor the quality of all hose and electrical connections;
- d) Do not forget to adjust the tension of the accelerator cable (see Section Removing, installing and adjusting the accelerator cable).
Injectors and fuel line
Note. If you suspect a malfunction of the injectors, you should not immediately proceed to their removal. First try to clean the injectors by adding a special additive to the fuel (ask at auto chemical stores).
Removing
1. Relieve the pressure in the supply system (see Section Release of residual pressure in the power system).
2. Disconnect the negative cable from the battery.
3. Remove the top cover of the throttle body (see Section Removing and installing the air cleaner assembly).
4. Having previously marked, disconnect the electrical wiring from the injection injectors.
5. Release the harness from the clips on the top of the fuel line and slide it to the side.
6. Disconnect the vacuum hose from the fitting on 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 flow direction factory markings).
8. Turn out two fixing bolts and accurately remove a fuel highway together with injectors of injection from the inlet pipeline. Make sure that when removing the injectors from the seats in the line, the lower sealing rings remain in their regular places.
9. Injectors can be removed from the line individually by removing the metal clips. Remove the top o-rings of the injectors.
10. If necessary, remove the fuel pressure regulator.
11. Using a universal tester, measure the electrical resistance of each of the injectors. Compare measurement results with requirements Specifications.
Installation
Installation is in the reverse order. Pay attention to the following points:
- a) Don't forget to check the condition of the injector o-rings. Defective rings must be replaced;
- b) Follow the reliability of the fit of the metal clamps for fastening the injectors;
- c) Follow the correct connection of the fuel supply and return hoses to the line;
- d) Monitor the quality of all hose and electrical connections;
- e) Before operating the vehicle, check the power supply system for leaks.
Fuel pressure control
Removing
1. Relieve the pressure in the supply system (see Section Release of residual pressure in the power system).
2. Disconnect the negative cable from the battery.
3. Remove the top cover of the throttle body (see Section Removing and installing the air cleaner assembly).
4. Disconnect the vacuum hose from the union on the bottom of the pressure regulator.
5. Loosen the clamp and disconnect the fuel supply hose from the line. In this case, most of the fuel contained in the line will spill out - prepare a small drain container and place a rag under the regulator assembly.
6. Remove the mounting clip from the upper part of the regulator body fixed to the end of the fuel line. Remove the regulator with o-rings.
Installation
Installation is in the reverse order. Pay attention to the following points:
- a) Worn o-rings must be replaced without fail;
- b) Track the reliability of the fit of the latch;
- c) Check the tightness of the vacuum hose connection.
Throttle position module
The module is mounted in the throttle body and cannot be replaced individually. In case of problems, seek help from car service specialists.
Intake air temperature/pressure sensor
Removing
1. The sensor is installed on the right side of the intake manifold.
2. Disconnect the negative cable from the battery.
3. Remove the top cover of the throttle body (see Section Removing and installing the air cleaner assembly).
4. Disconnect the wiring from the sensor.
5. Remove the two mounting screws and remove the transmitter from its seat in the pipeline.
Installation
Installation is in the reverse order. Track reliability of a tightening of fixture.
Coolant temperature sensor
The fuel injection system coolant temperature sensor is part of the temperature meter sensor (CTS).
Oxygen sensor (λ probe)
See Section Removal and installation of λ-probe.
Electronic control unit (ECU)
The ECU is located at the rear on the left bulkhead of the engine compartment. The block 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 result in malfunction of the ECU.
Fuel pump relay and fuses
1. The fuel pump relay and injection system fuses are located in the mounting block installed in the vehicle interior (see chapter Onboard electrical equipment).
2. The pump relay is in the fifth position in the relay row of the operating panel of the mounting block. The electrical circuit of the pump power circuit is protected by fuse No. 4.
3. The relay is removed from its socket by simple pulling. The installation of the relay is unambiguous due to the asymmetry of the shape of the socket.
4. The fuse is removed in the same way as all other fuses (see chapter Onboard electrical equipment).
5. It should be noted that the removal of the main fuse of the injection system (№1) causes the adaptation data to be erased from the ECU memory, just like when the battery is disconnected. Reloading 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.