Idle speed control valve - removal and refitting

Note: A new gasket must be used when refitting the valve.

2.0 litre SOHC models
1 Disconnect the battery negative lead.

2 Disconnect the idle speed control valve wiring plug by releasing the retaining clip and pulling on the plug, not the wiring (see illustration).

13.2 Disconnecting the idle speed control valve wiring plug
13.2 Disconnecting the idle speed control valve wiring plug

3 Unscrew the two retaining nuts and withdraw the valve from the inlet manifold (see illustration). Recover the gasket.

13.3 Unscrewing an idle speed control valve retaining nut
13.3 Unscrewing an idle speed control valve retaining nut

4 Clean the valve and manifold mating faces before refitting, taking care not to allow dirt to enter the manifold.

5 Refitting is a reversal of removal, using a new gasket.

6 On completion, start the engine and check that the idle speed is stable if not, check for air leaks around the valve. Switch on all available electrical loads and check that the idle speed is maintained - if not, suspect a faulty valve.

2.0 litre DOHC models
7 Disconnect the battery negative lead.

8 Loosen the securing clip, and disconnect the air inlet hose from the throttle body.

9 Unscrew the securing nut, and release the air inlet tube from the bracket on the engine compartment front panel.

10 Disconnect the wiring plug from the idle speed control valve.

11 Release the air cleaner lid securing clips then remove the air inlet tube, plenum chamber, and air cleaner lid as an assembly, disconnecting the breather hose from the air inlet tube.

12 Unscrew the two securing bolts, and withdraw the valve from the air inlet tube.

Recover the gasket (see illustration).

13.12 Withdrawing the idle speed control valve and gasket
13.12 Withdrawing the idle speed control valve and gasket

13 Clean the valve and air inlet tube mating faces before refitting, taking care not to allow dirt to enter the air inlet tube.

14 Refitting is a reversal of removal, using a new gasket.

15 On completion, start the engine and check that the idle speed is stable if not, check for air leaks around the valve. Switch on all available electrical loads, and check that the idle speed is maintained - if not, suspect a faulty valve.

Mixture adjustment potentiometer (2.0 litre DOHC) - removal and refitting

1 The potentiometer is located at the rear right-hand side of the engine compartment, behind the MAP sensor.

2 Disconnect the battery negative lead.

3 Remove the screw, then withdraw the potentiometer and disconnect the wiring plug.

4 Refitting is a reversal of removal.

    See also:

    Diagram 1a: 1986-on Starting, charging, and ignition (except fuel injection) all models
    Diagram 1a: 1986-on Starting, charging, and ignition (except fuel injection) all models ...

    Roadwheel check (Every 12 000 miles or 12 months)
    Check the wheel rims for distortion, damage and excessive run-out. Also make sure that the balance weights are secure with no obvious signs that any are missing. Check the torque of the wheel bolt ...

    Engine electrical systems
    General information and precautions General information The electrical system is of the 12 volt negative earth type, and consists of a 12 volt battery, alternator with integral voltage regulator, ...