Fiat Bravo Service Manual page 178

Bravo-Brava gpi
16v
Engine
Fuel system
10.
BUTTERFLY VALVE CASE (54 CFA 26)
The butterfly valve case is responsible for metering the quantity of air supplied to the engine (and thus
controlling engine power output) according to accelerator position determined by the driver.
The butterfly valve case is fastened to the intake manifold by four screws. The throttle is opened by a
linkage with configuration designed to open the throttle by a small amount when the pedal is hardly
pressed (provided pedal travel remains the same) and open it by large amounts when the pedal is
pressed down further.
With the pedal fully released (engine in over-run or idling), the additional air required is supplied by an
engine idle adjustment solenoid. Under these conditions, the throttle opening lever comes into contact
with an anti-bind screw, which prevents the throttle becoming locked in closed position.
To prevent the build-up of ice around the throttle and the hole leading to the PCV valve, the butterfly
valve case is heated by directing a small amount of coolant from the engine thermostat around a cham­
ber inside the case.
The oil vapour recirculation system PCV valve and throttle position sensor are also fitted on the butterfly
valve case.
The anti-bind screw is
set by flushing in the
factory and should nev­
er be tampered with.
1. Throttle linkage
2. Butterfly valve adjustment and antibind screw (do not touch)
3. Attachment for engine coolant delivery hose
4. Engine idle speed actuator
5. Attachment for engine coolant return hose
6. Throttle position sensor
7. Throttle valve
8. Attachment for engine block vapour recirculation and recovery line
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