Fiat Bravo Service Manual page 179

Engine
Fuel system
Bravo-Brava tip
lev
10.
THROTTLE VALVE POSITION
SENSOR (WEBER PF-1C)
This takes the form of a potentiometer whose
mobile part is controlled by the butterfly
valve spindle.
The potentiometer is fitted inside a plastic
container equipped with two tabs containing
two UNSLOTTED holes. These anchor the
sensor and ensure it is positioned correctly in
relation to the throttle valve. A three-pin
socket (ABC) on the container provides an
electrical connection with the injection-igni­
tion ECU.
During operation, the ECU supplies the po­
tentiometer at a voltage of 5 Volt. The pa­
rameter measured is throttle position from
idle to full opening for injection control man­
agement.
The following graph indicates the voltage
level supplied by the sensor as a function of
throttle opening angle.
i
V
5"
015-
(
k
y
/ .
u
[_+3^
)° 105° ^Z°
The ECU recognises throttle valve opening
status on the basis of outlet voltage and cor­
rects mixture concentration accordingly.
When the throttle is closed, an electric volt­
age signal is sent to the ECU, which recog­
nises idle and cut-off status (discerning be­
tween them on the basis of rpm level).
The potentiometer is single-ramp: its main
specifications are as follows:
Effective electrical angle: 90° ± 2°
Mechanical angle: 105° ± 4°
Total mechanical travel: 110° ± 8°
Temperature service range: -30°C + +125°C
32
Publication no. 506.670