Fiat 1996 Brava Service Manual page 423

Bravo-Btava ^
'98 range
16v
Engine
Fuel system
10.
When examining the voltages required for the spark between the plug electrodes, it may be noted that in
the cylinder at the compression stroke, this voltage is high (over 10kV) while in the cylinder in the ex­
haust stroke the voltage is low (about 5kV).
The high voltage distribution is static, i.e. characterized by the absence of a rotor arm and cap, and thus
the distributor is in effect eliminated. This offers a considerable advantage to the system as it is known
that the insulation characteristics of the rotor arm and cap play a fundamental role; any dispersion of in­
sulation towards earth can be detrimental to ignition, especially during winter or in heavy rain.
The spark plugs of cylinders 1 -4 and 2-3 are connected directly (two by two) by high tension cables to
the terminals of the coil's secondary winding, and their connection may be considered to be serial as the
cylinder head joins them. This solution is also called "lost spark" as the energy accumulated by the coil
will be almbsYexclusively discharged on the electrodes of the spark plug located ini the cylinder under
compression, allowing the mixture to be ignited. The other spark is naturally not used, as there is no mix­
ture to be ignited in the cylinder, only an environment of used gas at the exhaust stage.
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1. Rpm and TDC sensor
2. Crankshaft pulley with phonic wheel
3. Battery
4. Ignition switch
5. Spark plugs
6. Ignition coils
7. Fuel injection relay
8. Fuel injection-ignition electronic control
unit
9. Fuel injection-ignition system fuse
10. Fuse protecting fuel injection-ignition
control unit
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