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4•6 ignition system – FIAT Uno 45 User Manual

Page 77

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Reassembly

14 This is a reversal of dismantling. On
Ducellier distributors, make sure that the
advance toothed segment is returned to its
original setting otherwise the advance curves
for your particular engine will be upset.

8

Ignition coil (mechanical
breaker ignition)

1 Coils normally last the life of a car. The
most usual reason for a coil to fail is after
being left with the ignition switched on but the
engine not running. There is then constant
current flowing, instead of the intermittent
flow when the contact breaker is opening. The
coil then overheats, and the insulation is
damaged (photo).
2 If the coil seems suspect after fault finding,
the measurement of the resistance of the
primary and secondary windings (usually an
ohmmeter) can establish its condition. If an
ohmmeter is not available, it will be necessary
to try a new coil.

9

Digiplex (electronic) ignition
- location of components and
precautions

1 The main components of this system are
located within the engine compartment as
shown.
2 On cars equipped with this system, it is

4•6 Ignition system

Fig. 4.7 Main components of Digiplex ignition system (Sec 9)

8.1 Ignition coil

Fig. 4.6 Exploded view of typical Ducellier distributor (Sec 7)

1 Cap
2 Rotor
3 Movable breaker arm
4 Vacuum advance link
5 Fixed contact breaker arm
6 Contact breaker baseplate
7 Cam assembly

8 Centrifugal advance weight

control springs

9 Driveshaft and plate

10 Body
11 LT insulator
12 Condenser
13 Vacuum capsule

14 Cap retaining spring
15 Thrust washer
16 Spacer washer
17 Driving dog
18 Retaining pin
19 Felt pad

7.13 Marelli distributor centrifugal weights

and springs

1 Control unit
2 Cut-out control unit
3 Ignition coil
4 Flywheel (engine

speed) sensor

5 Crankshaft pulley

(TDC) sensor

6 Vacuum hose

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