Fiat Bravo Service Manual page 387

Engine
Fuel system
Bravo &) 2ov
10.
Checking the resistance
The resistance of the sensor heater can be
measured by disconnecting the connector
and connecting an ohmmeter as shown in
the diagram.
Resistance: 4.5 ± 0.5 ohm at 20 °C
CHARCOAL FILTER AND FUEL VAPOUR
CUT OUT SOLENOID VALVE
The charcoal filter and the solenoid valve are
located in the right wheel arch.
For the description of the charcoal filter refer
to the Fuel System section for the 1581 16V
engine.
1. Vapour cut out solenoid valve
2. Charcoal filter
Vapour cut out solenoid valve
(0.280.142.300)
The function of this valve is to control the
quantity of petrol vapours drawn in by the
active charcoal filter and directed to the inlet
manifold by means of the electronic control
unit.
If this valve is not supplied it is in the open po­
sition; if the key is turned to the ON position, it
closes preparing for operation. In effect, if en­
ergized the solenoid valve (6) attracts the shut­
ter (4) which, overcoming the spring (3) load­
ing, closes the port (5) preventing the flow of
petrol vapours.
The operation is controlled by the electronic
control unit as follows:
- during starting the solenoid valve remains
closed, preventing the petrol vapours from
excessively enriching the mixture;
- when the engine has been started up, the
electronic control unit sends a signal to the
solenoid valve which modulates the open­
ing.
In this way the control unit controls the
quantity of petrol vapours sent to the inlet,
thereby preventing considerable variations
(above all during idling) in the mixture
strength.
NOTE The solenoid valve must be fitted
correctly: the arrow on its casing
should be facing the vacuum inlet on
the inlet manifold.
1. Inlet union
2. One-way valve
3. Spring
4. Shutter
5. Outlet port
6. Solenoid valve
7. Outlet union
36 Print no. 506.670