Butterfly Casing; Engine Idle Speed Actuator Aa And Butterfly Position Sensor - Fiat Bravo Service Manual

E n g i n e
Fuel system
10.
1. accelerator control lever
2. idle speed adjustment actuator and but-
terfly position sensor
3. accelerator cable adjustment bracket
4. anti-tamper screw
30
B U T T E R F L Y C A S I N G
The butterfly casing has the task of metering
the quantity of air drawn in by the engine
(and consequently the power developed) ac-
cording to the driver's request via the acceler-
ator.
The butterfly casing is fixed to the inlet mani-
fold: the butterfly is opened by means of a
lever w h i c h has a gradual opeing law (small
butterfly opening angles for a good part of
the accelerator pedal travel and greater an-
gles in the last part of the travel.
With the pedal completely released (engine
decelerating or idling) the position of the
butterfly is regulated by the engine idle ad-
justment actuator in order to be able to sup-
ply the additional air required according to
P4A30JJ01
the engine conditions. The actuator also i n -
cludes the butterfly position sensor.
ENGINE I D L E S P E E D ACTUATOR AAAND
B U T T E R F L Y POSITION SENSOR
The actuator, fitted on the butterfly casing,
consists of a direct current motor operated by
a circuit inside the engine control unit w h i c h
regulates the position of the butterfly: it has
the task of ensuring the additional air for the
engine w i t h the accelerator pedal released,
under all circumstances when
(idling, deceleration, external loads applied).
The maximum actuator opening angle is
around 30°.
The actuator contains a t w i n track poten-
tiometer:
- the first track goes from the closed position
to 30° and is used to control the butterfly
with the accelerator pedal released;
- the second track goes from the closed po-
sition to the maximum butterfly opening
position and is used for the normal engine
management.
Wiring connector
P4A30JJ03
Bravo-Brava i g i lev
98 range
necessary
Print no. 506.670/16