Checking the operation, removing and installing the throttle body (BMW 5 Series E28)

Examination

1. Disconnect the air intake duct from the throttle body (see section Removal and installation the air cleaner) and take it aside.

2. Observe the throttle valve while the assistant presses the accelerator pedal. Check that the throttle valve moves smoothly from the closed position (idling) until fully open (full speed).

3. If the throttle valve does not operate properly, replace the throttle body assembly.

Wait until the engine has cooled down completely before performing this procedure.

If your car radio has an anti-theft system, make sure you know the correct activation code before disconnecting the battery. Before disconnecting the wire, refer to Section Anti-theft audio system and instrument cluster language.

If a message in another language appears on the instrument panel display after disconnecting the battery, refer to Section 1 for the language setting procedure Anti-theft audio system and instrument cluster language.

Removal and installation

1. Disconnect the negative battery cable.

2. Disconnect the intake air duct from the throttle body and move it to the side.

3. Disconnect the accelerator cable from the throttle body (see section Checking, adjusting and replacing the accelerator cable).

4. If used, disconnect the cruise control cable.

5. Clearly label all electrical connections (throttle position sensor, cold start injector, idle air supply stabilizer and others), then disconnect them.

6. Clearly label all vacuum hoses, then disconnect them.

7. To relieve any residual pressure in the cooling system, loosen the radiator or expansion tank cap, then screw it back on. Clamp the coolant hoses, then loosen the hose clamps and disconnect the hoses. Be prepared for a small amount of coolant to leak out.





8. Loosen the nuts (top) and bolts (bottom) securing the throttle body and disconnect the throttle body from the intake manifold flange.

9. Cover the intake manifold flange opening with a clean cloth to prevent dirt and dust from entering when the throttle body is removed.

10. Installation is the reverse of removal. Tighten the throttle body mounting nuts to the specified torque Table of sizes and adjustment data at the end of the Manual with force and then adjust the accelerator cable (see section Checking, adjusting and replacing the accelerator cable).