Fiat 1998 Marea Weekend, Service Manual

Page: 248 / 846

Engine
Fuel system
16v
Marea- Marea Weekend ft
99 range
10.
9*
NC NA C
N C % NA
I * J
INERTIA SAFETY SWITCH
The inertia switch has the task of cutting off
the electrical supply for the electric fuel pump
if the vehicle suffers violent deceleration (im-
pacts) to prevent the escape of fuel in case the
fuel manifold or the supply pipe is damaged
with a consequent risk of fire.
The switch consists of a steel ball fitted in a
conical shaped housing kept in position by the
attraction force of a permanent magnet.
Under the action of the acceleration due to in-
ertia forces, the ball may be released from the
magnetic clip 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 located
above the ball which forms a normally closed
(NC) circuit. When the mechanism is struck by
the ball, it changes position into a normally
open (NA) circuit, thereby interrupting the
electrical supply to the electric pump and
causing it to cut out.
The calibration of the switch causes it to inter-
vene at acceleration above 1.2 g (approx 11.7
m/s2, corresponding to an impact at a speed
of around 25 km/h).
To restore the connection to earth for the aux-
iliary electric pump, the seat must be moved
backwards and the switch pressed until a click
is heard.
After even an apparently slight impact, if there is a smell of fuel or there are leaks from the fuel
system, do not turn the switch back on, but search for the cause of the problem and remedy it
to avoid the risk of fire.
If there are no leaks and the vehicle is ready to depart once again, press the button to reactivate
the electric pump.
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