Fiat Uno Manual

Carburettors (Weber 32 ICEE/ 250 and Solex C32 DISA 14) - description and adjustment
Fuel system / Carburettors (Weber 32 ICEE/ 250 and Solex C32 DISA 14) - description and adjustment

1 One of these carburettors is used on 903 cc ES engines. They are very similar to the Weber 32 ICEV 50/250 and Solex C32 DISA 11 already described in this Chapter except that a fuel cut-out solenoid valve is fitted in association with the Digiplex ignition system (see Chapters 4 and 9).

2 The solenoid valve cuts off the supply of fuel to the carburettor whenever the accelerator pedal is released during overrun conditions.

3 A fuel cut-out device control unit receives information regarding engine speed from the static ignition control unit.

4 A throttle butterfly switch relays information that the accelerator pedal is in the released state.

5 At certain minimum idle speeds during deceleration, the fuel cut-out solenoid valve is re-energised so that engine idling is maintained without the tendency to cut out.

6 The Solex type control unit varies the fuel cut-out point according to the deceleration value.

Fault testing
7 Should a fault develop, connect a test lamp between the fuel cut-out solenoid switch and a good earth.

8 Connect a reliable tachometer to the engine in accordance with the makerís instructions.

9 Start the engine and raise its speed to between 3000 and 4000 rev/min, then fully release the accelerator pedal.

10 The test lamp should only go out during the period when the accelerator pedal is released. Should the test lamp remain on all the time, or never come on, check the throttle switch earth and the solenoid switch connections.

11 Disconnect the multi-plug from the control unit. Switch on the ignition and check that a test lamp connected between contact 7 of the multi-plug and earth will illuminate. If it does not, there is an open circuit from connection 15/54 of the fuel cut-off switch.

12 Switch off the ignition and check for continuity between contact 3 of the multiplug and earth. An ohmmeter will be required for this test.

13 If there is no continuity (ohmmeter shows infinity), check all the system earth connections. Also check that the wiring plug under the control unit is properly connected.

14 Finally, check the engine speed signal. To do this, a tachometer must be connected to the single socket under the control unit within the engine compartment.

15 If the tachometer registers correctly then this confirms that the electronic ignition control unit is functioning, if the tachometer does not register, renew the ignition control unit.

16 If a replacement carburettor is to be fitted, only fit the Solex assembly including the control module, even if a Weber was originally fitted.

Fig. 3.21 Sectional view of fuel cut-off switch (Solex C32 DISA 14) (Sec 11)
Fig. 3.21 Sectional view of fuel cut-off switch (Solex C32 DISA 14) (Sec 11)

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