B1 - B5 Air Leakage, Throttle Switch, Idle Speed

B1 Check Induction System For Leakage
If air leaks from point where air mass meter is mounted on engine, air/fuel mixture will be lean.

- Check inlet system between air mass meter and intake manifold.
- Check all hoses and connections on intake manifold.
- Check couplings and seals for intake manifold, throttle housing, etc.

B2 Throttle Housing





- Check throttle housing for dirt.

To Clean:
- Disconnect the connector from throttle switch.
- Remove throttle housing and clean with a suitable solvent.
- Keep throttle switch dry.

IMPORTANT A dirty throttle housing indicates a blocked, incorrectly fitted or damaged air filter.

B3 Install Throttle Housing





Use a new gasket.
- Connect hoses and throttle switch connector.

B4 Basic Adjustment Of Throttle Shutter
The throttle is adjusted at the factory and normally requires no further adjustment unless mechanical problems are suspected.





- Remove link rod from throttle pulley.
- Loosen throttle switch attaching screws (3 mm Allen)





- Loosen lock nut on adjustment screw.
- Loosen adjustment screw until throttle is completely closed.
- Tighten adjustment screw until it contacts link rod and then tighten an additional 1/2 turn. Tighten lock nut and make sure that adjustment screw does not turn during this procedure.
- Adjust throttle switch.

B5 Check Adjustment Of Throttle Switch





- Open throttle switch slightly and listen. A click should be heard to indicate that switch actuates.

Adjust/Check Throttle Switch Setting
- Slacken retaining screw (3 mm Allen).
- Turn switch clockwise slightly.
- Turn switch back again until a click is heard.
- Tighten retaining screws.
- Recheck setting.

Check Idle Speed

NOTE: Engine should be warmed-up until radiator thermostat opens and then for a further 10 minutes. Switch off air conditioning.

- Connect a tachometer.





- Ground blue-white wire from test point to close air control valve.
- Idle speed should be: 700 rpm.
- Adjust idle speed if necessary.





- Adjust idle speed with idle adjustment screw.

- Disconnect ground wire from test point.
- Idle speed should increase to: 750 +20 rpm.

NOTE: It is occasionally necessary to slacken throttle switch to obtain correct setting.