Throttle Body (Multec System) — Removal and Installation (Opel Vectra A)

Removal

1. Depressurize the fuel system (Chapter 8).

2. Remove the heater block (see above).

3. Disconnect the negative cable from the battery.

4. Disconnect the wiring from the fuel injector (squeeze out the rubber shell sealing ring) from the idle air control stepper motor and from the potentiometer.

5. Disconnect the fuel supply hoses from the couplings; plug them to prevent fuel loss and dirt from entering the block; mark their location so as not to get confused during installation.

6. Disconnect the vacuum hoses and pipes from the couplings on the body.

7. Disconnect the throttle control rod from the throttle body.

8. Unscrew the two nuts securing the throttle body to the intake manifold and remove the assembly; remove and discard the gasket (see illustration).



9. If required, the upper and lower parts of the throttle body can be separated by unscrewing the two mounting screws; please note that a new gasket must be used during assembly. You can also unscrew the fuel supply and return couplings, but please note that new support rings must be installed during assembly.

Installation

10. Installation is carried out in the reverse order of removal, but pay attention to the following (see illustration).

• a) Replace all gaskets and seals, use thread locking compound.
• b) Check the operation and adjustment of the throttle cable (see above).
• c) When connecting the vacuum hoses and tubes, make sure they are connected to the front couplings as shown in the photograph.
• d) Due to the lack of a fuel vapor trap, it is very important that the manifold pressure sensor vacuum hose is routed straight (horizontally) from the sensor to the throttle body. This will prevent fuel drips from the sensor or hose from entering the inlet channel.
• e) Make sure that the fuel supply hoses are connected correctly; the supply hose is located on the side of the throttle body where the injectors are located.
• j) Turn on the ignition and check for fuel leaks; if any signs of a leak are detected, the problem must be corrected before the engine is started.