Exhaust emission control system components - removal and refitting

Carburettor engines Spark delay/sustain valve Removal
1 Disconnect the vacuum lines at the valve and remove the valve from the engine.

2 When refitting a spark delay valve it must be positioned with the black side (marked CARB) towards the carburettor and the coloured side (marked DIST) towards the distributor. When refitting a spark sustain valve the side marked VAC must be towards the carburettor and the side marked DIST towards the distributor.

Ported vacuum switch
3 Remove the filler cap from the expansion tank to reduce pressure in the cooling system.

If the engine is hot, remove the cap slowly using a rag to prevent scalding.

4 Disconnect the vacuum lines and the water hoses, then unscrew the valve.

5 When refitting the valve, note that the vacuum line from the carburettor is connected to the middle outlet on the PVS, the vacuum line from the spark delay valve (where fitted) is connected to the outlet nearest to the threaded end of the PVS, and the vacuum line from the spark sustain valve is connected to the outlet furthest from the threaded end of the PVS.

6 Reconnect the water hoses and if necessary top-up the cooling system.

Fuel trap
7 Disconnect the vacuum lines and remove the fuel trap from the engine.

8 When refitting, make sure that the fuel trap is positioned with the black side (marked CARB) towards the carburettor and the white side (marked DIST) towards the PVS (see illustration).

7.8 Fuel trap marked for direction of fitting
7.8 Fuel trap marked for direction of fitting

Central Fuel Injection (CFI) engines
Catalytic converter
Note: Handle the catalyst with care. Any sudden knocks can cause damage to the internal substrates
9 Disconnect the battery negative lead.

10 Apply the handbrake, then jack up the front of the vehicle and support it securely on axle stands (see “Jacking and Vehicle Support”).

11 Remove the bolts from the exhaust downpipe-to-catalytic converter flanged joint.

12 Unscrew the nuts, and remove the clamp securing the rear of the catalytic converter to the exhaust system.

13 Unhook the catalytic converter from the rubber mountings, and carefully manipulate the converter from under the vehicle. If necessary, unhook the front end of the exhaust system from the rubber mountings to ease the procedure.

14 Commence refitting by ensuring that the mating faces of the catalytic converter, downpipe, and exhaust system are clean.

15 Examine the mounting rubbers, and renew if necessary, noting that the rubbers used are of a special high temperature type due to the high operating temperature of the catalyst.

16 Loosely fit the catalytic converter in position, but do not tighten the fixings yet.

Use a new gasket at the converter-todownpipe flanged joint.

17 Carefully align the downpipe, converter and exhaust system, then tighten the fixings.

18 Lower the vehicle and reconnect the battery negative lead, then start the engine and check the exhaust system for leaks.

Heater Exhaust Gas Oxygen (HEGO) sensor
19 Refer to Part C of this Chapter.

    See also:

    Camshafts and cam followers - removal, inspection and refitting
    Note: Once the timing chain has been removed from the camshaft sprockets, do not turn the crankshaft until the timing chain has been correctly refitted - this is to prevent contact between the val ...

    Crankshaft and bearings - examination and renovation
    1 Examine the bearing surfaces of the crankshaft for scratches or scoring and, using a micrometer, check each journal and crankpin for ovality. Where this is found to be in excess of 0.0254 mm (0. ...

    Ignition systems
    The ignition system is divided into two circuits, low tension (primary) and high tension (secondary). The low tension circuit consists of the battery, ignition switch, primary coil windings and th ...