Specifications of ignition system of Fiat Punto

General
System type .............................................. Static (distributorless) ignition system controlled by engine management ECU
Firing order ..........................................       1-3-4-2 (No 1 cylinder at timing belt end of engine)
Ignition timing............................................. Controlled by engine management ECU

Ignition coil
Resistances (at 20° C):
Primary windings ........................................ 0.52 to 0.62 ohms
Secondary windings...................................... 6,83 to 7.33 k ohms
Torque wrench setting                                         Nm            lbf ft
Knock sensor securing bolt .................................. 20               16


General information

The ignition system of Fiat Punto is integrated with the fuel injection system to form a combined engine management system under the control of one ECU.
The ignition side of the system is of the static (distributorless) type, consisting only of two twin-output ignition coils located on the left-hand side of the cylinder head. Each ignition coil supplies two cylinders (one coil supplies cylinders 1 and 4, and the other cylinders 2 and 3). Under the control of the ECU, the ignition coils operate on the wasted spark principle, i.e. each spark plug sparks twice for every cycle of the engine, once on the compression stroke and once on the exhaust stroke. The spark voltage is greatest in the cylinder which is under compression, the other cylinder having a very weak spark which has no effect on the exhaust gases. The ECU uses its inputs from the various sensors to calculate the required ignition advance setting and coil charging time depending on engine temperature, load and speed.
A knock sensor of Fiat Punto is also incorporated into the ignition system. Mounted onto the cylinder block, the sensor detects the high-frequency vibrations caused when the engine starts to pre-ignite, or 'pink'. Under these conditions, the knock sensor sends an electrical signal to the ECU which in turn retards the ignition advance setting in small steps until the 'pinking' ceases.