Ignition coil unit (552), Simtec
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Ignition coil unit (552), Simtec
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Ignition coil unit (552)
The ignition coil has the following task:
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Generate the high-voltage spark that starts the combustion.
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These signals are used for knock control, synchronisation of ignition timing/fuel injection and for misfire detection.
Assembly with 4 inductive ignition coils.
Pin No.
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Signal type
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Description
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2
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B-, in
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+15 power supply from fuse 4 (342)
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3
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Ignition trigger, in
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Ignition trigger, cyl 4 from ECM.
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4
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Ignition trigger, in
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Ignition trigger, cyl 3 from ECM.
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5
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Ignition trigger, in
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Ignition trigger, cyl 2 from ECM.
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6
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Ignition trigger, in
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Ignition trigger, cyl 1 from ECM.
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The unit contains four individual ignition coils. The ignition coil is a transformer whose primary winding is supplied +15 (pin 2 on the ignition coil unit). The current through the primary winding is regulated by ECM. When ECM grounds one side of the primary winding, a current flows through the same. The time during which this current flows is called cam angle or charging time. When current ceases, the spark is fired. This time point is the same as the actual ignition angle. ECM determines both the ignition coil charge time (cam angle) and the ignition angle.
Wiring diagram