Fiat 1996 Brava Service Manual page 285

Engine
Fuel system
10.
Bravo-Brava l$i 16v
98 range
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I N C X NA
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NC NA C
INERTIA SAFETY SWITCH
The inertia switch has the task of interrupting
the electrical supply for the electric fuel pump
if the vehicle is subject to violent deceleration
(an impact) to prevent the fuel from coming
out and causing the vehicle to catch fire in
case the fuel manifold or the supply pipe is
damaged.
The switch consists of a steel ball in a conical
shaped housing which is kept in position by
the attraction force of a permanent magnet.
The ball can be released from the magnetic
clip, due to the action of the acceleration
from the inertia forces, and gradually come
out of the conical housing with an upwards
movement which depends on the angle of
the cone.
There is a rapid release mechanism which
forms a normally closed (NC) circuit. When
it is struck by the ball, the mechanism
changes position into a normally open (NA)
circuit, thereby interrupting the electrical
supply to the electricpump and causing it to
cut out.
The calibration of the switch causes it to in­
tervene at acceleration above 1.2 g (approx
11.7 m/s2, corresponding to an impact at a
speed of around 25 kph).
To restore the connection to earth for the
auxiliary electric pump, move the seat back­
wards and press the switch until the click is
heard.
After even an apparently slight impact, if there is a smell of fuel or there are noticeable leaks from
the fuel system, do not turn the switch back on, but search for the cause of the problem and
eliminate it to avoid fire hazards.
If this is not the case and there are no leaks and the vehicle is ready to be driven again, press the
button to reactivate the electric pump.
34 Print no. 506.670/16