Contents: Throttle body ⬇ Injectors and fuel rail ⬇ Fuel pressure regulator ⬇ Throttle Position Module ⬇ Intake air temperature/pressure…⬇ Coolant temperature sensor ⬇ Oxygen sensor (λ-probe) ⬇ Crankshaft speed and position sensor ⬇ Knock sensor ⬇ Electronic Control Unit (ECU) ⬇ Fuel Pump Relays and Fuses ⬇
Note: See the warnings given in Section General information and precautions.
For the MPFI component connection diagram, see Section Removal and installation of Magneti-Marelli 1AV injection system components.
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 vacuum hose from the cylinder head cover and the carbon canister hose from the throttle body.
6. Remove the four through bolts and remove the throttle body from the intake manifold. Also remove the gasket (during assembly it must be replaced without fail).
Installation
Installation is carried out in reverse order. Please note the following points:
- a) Don't forget to replace the sealing gasket;
- 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 throttle body and air cleaner upper covers (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.
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6. Disconnect the fuel supply and return hoses from the end of the fuel line. Try to remember the installation position of the hoses - the supply hose is located closer to the throttle body.
7. Disconnect the vacuum hose from the front of the fuel pressure regulator.
8. Also disconnect the small hose from the cylinder head cover...
...and the carbon canister hose from the retainer at the rear of the fuel line.
9. Unscrew the two mounting bolts and carefully remove the fuel line together with the injection injectors from the intake manifold. To avoid fuel spillage, try not to tilt the line. Make sure that when removing the injectors from their mounting seats in the line, the sealing rings remain in their regular places.
10. Injectors can be removed from the line individually by removing the metal clips.
11. Remove the upper injector sealing rings. Check the condition of the rings.
12. If necessary, remove the fuel pressure regulator (see below).
13. 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 throttle body and air cleaner upper covers (see section Removal and installation the air cleaner assembly).
4. Disconnect the vacuum hose from the front of the pressure regulator.
5. To collect spilled fuel, place a rag under the regulator unit.
6. Remove the bolt located under the vacuum fitting of the regulator.
7. Remove the washer and mounting plate from the front of the regulator.
8. Remove the regulator from its original location on the fuel line. Make sure that the sealing gaskets are removed along with the regulator.
Installation
Installation is carried out in reverse order. Please note the following points:
- a) Worn sealing rings must be replaced without fail;
- b) Ensure that the upper part of the mounting plate is properly engaged. Tighten the bolt to the required torque;
- 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 at the rear of the intake manifold.
2. Disconnect the negative cable from the battery.
3. Remove the throttle body and intake manifold upper covers (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. Do not forget to remove the gasket.
Installation
Installation is carried out in the reverse order. A damaged gasket must be replaced. 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.
Crankshaft speed and position sensor
See Chapter Engine electrical equipment.
Knock sensor
See Chapter Engine electrical equipment.
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
The fuel pump relay and injection system fuses are located in the mounting block installed in the passenger compartment of the vehicle (see Chapter On-board electrical equipment).
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.
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.
The fuse is removed in the same way as all other fuses (see Chapter On-board electrical equipment).
It should be noted that removing the main injection system fuse (No. 1) erases 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 instability of the idle speed during the first few minutes after the engine is first started.