Fiat 1998 Marea Weekend, Service Manual

Page: 310 / 846

Engine
Fuel system
16v
Marea- Marea Weekend ft
99 update
10.
r
X 7 —
I
NCV
! \
N C % NA
I
NC NA C
1. Inertia sensor
2. Button for restoring operation of electric fuel
pump
INERTIA SAFETY
SWITCH
In order to improve the safety of the occupants
of the vehicle in the case of an impact, the vehi-
cle is equipped with an inertia switch, located
under the dashboard on the driver's side, fas-
tened to the left side panel, near the bonnet re-
lease.
The inertia switch has the task of interrupting
the electrical supply for the fuel pump if the ve-
hicle undergoes violent deceleration (impact) to
prevent fuel from being able to escape, if the
fuel manifold or the supply pipes are damaged,
and create a fire hazard.
The switch consists of a steel ball, fitted in a
conical shaped housing and kept in positino by
the attraction force of a permanent magnet.
As a result of the acceleration due to the
inertic
forces, the ball can be released from the mag-
netic clip and gradually come out of the tapered
housing with an upwards movements which de-
pends on the angle of the cone.
There is a rapid release mechanism, 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) cir-
cuit, thereby interrupting the electric supply to
the pump and causing it to cut out.
The calibration of the switch causes it to inter-
vene at accelerations of above 1.2 g (about 11.7
m/s
2
, corresponding to an impact at a speed of
about 25 Km/h).
The switch can be turned back on by pressing
the top button with the protective cover.
Even after an apparently slight impact, if there is a smell of fuel or there are leaks from the fuel
system, the switch should not be turned back on, but the cause of the problem sought and reme-
died to prevent the risk of fire.
If this is not the case and there are no leaks, the vehicle can be driven again and the button
should be pressed to reactivate the pump.
40
Print n° 506.763/75