Fiat 1998 Marea Weekend, Service Manual

Page: 361 / 846

Engine
Fuel system
20\
Marea- Marea Weekend fP>
99 range
10.
ANTI-EVAPORATION SYSTEM COMPONENTS
Charcoal filter and fuel vapour cut out solenoid valve
These components form part of the fuel vapour recovery and anti-evaporation system. The charcoal filter is
located in the right wheel arch; to gain access to it the rear section of the right front wheel arch liner has
to be removed.
The cut out solenoid valve is located in the engine compartment, under the inlet manifold.
Charcoal filter
It consists of granules of charcoal (4) which trap
the petrol vapours entering through the intake
(5).
The scavenging air which enters through the in-
take (1), passes through the paper filter (3),
comes into contact with the granules of charcoal
and removes the petrol vapours and directs them
towards the outlet (2) and from there to the cut
out solenoid valve.
The air, entering through the intake (5), can also
be recalled by the vacuum in the tank and used
for ventilation purposes. The partition (6) ensures
that the air introduced comes into contact with all
the granules of charcoal facilitating the release of
the petrol vapours to the inlet manifold.
There are also two springs (7) which allow the
expansion of the mass of granules when the pres-
sure increases.
Vapour cut out solenoid valve
(0.280.142.340)
The function of this valve is to control the quan-
tity of petrol vapours drawn in by the charcoal
filter and directed to the inlet manifold which is
achieved through the electronic control unit.
If this valve is not supplied it is in the open posi-
tion; when the key is turned to the ON position, it
closes and prepares for operation. In effect, if en-
ergized, the solenoid (6) attracts the shutter (4)
which, overcoming the loading of the spring (3),
closes the port (5), preventing the flow of petrol
vapours.
The operation is controlled by the electronic con-
trol unit as follows:
- during starting, the solenoid valve remains
closed, preventing the petrol vapours from ex-
cessively enriching the mixture;
- with the engine started up, the electronic con-
trol unit sends a signal to the solenoid valve
which modulates the opening.
In this way the control unit controls the quantity
of petrol vapours sent to the inlet, avoiding con-
siderable variations (above all during idling) in
the mixture strength.
1. Inlet connector
2. Single-acting valve
3. Spring
4. Shutter
5. Outlet port
6. Solenoid
7. Outlet connector
NOTE The solenoid valve must be fitted in the
correct position: the arrow on the casing
should be pointing towards the vacuum
intake on the inlet manifold.
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Print n° 506.763/14