900 L4-1985cc 2.0L SOHC Turbo VIN S FI (1984)
Auxiliary Air Valve (Idle Speed): Description and Operation
Fig. 15 Auxiliary Air Valve
The auxiliary air valve, Fig. 15, operates in conjunction with the warm up regulator to compensate for losses due to friction and condensation in the
intake manifold and combustion chamber during cold starting, so a constant idle speed can be maintained. The valve is located in a bypass passage
around the throttle plate. The air flowing through the auxiliary air valve has been metered by the air flow meter, so no unmetered air is introduced into
the air system. The valve is actuated by a bi-metallic strip that opens the valve when the engine is cold. When the engine is started, current flows
through a coil, heating the strip and gradually closing the valve. When a warm engine is started, the engine temperature causes the bi-metallic strip to
hold the valve in an open position.