Waveforms

Ignition system

Conventional distributor ignition (DI).

Voltage waveforms in primary and secondary circuits of a conventional distributor ignition system
Voltage waveforms in primary and secondary circuits of a conventional distributor ignition system
Voltage waveforms in primary and secondary circuits of a conventional distributor ignition system

Voltage waveforms in primary and secondary circuits of a conventional distributor ignition system. A conventional ignition system is defined as a system having a distributor and breaker points.
1 – secondary circuit;
3 – primary circuit.

Conventional distributor ignition (EI).

Voltage waveforms in primary and secondary circuits of a conventional electronic ignition system
Voltage waveforms in primary and secondary circuits of a conventional electronic ignition system
Voltage waveforms in primary and secondary circuits of a conventional electronic ignition system

Voltage waveforms in primary and secondary circuits of a conventional electronic ignition system. A conventional ignition system is defined as a system having a distributor and the primary current flow is controlled by an electronic module or transistor.
1 – secondary circuit;
3 – primary circuit.

Distributorless (DIS) ignition system.

Voltage waveforms in primary and secondary circuits of a DIS ignition system
Voltage waveforms in primary and secondary circuits of a DIS ignition system
Voltage waveforms in primary and secondary circuits of a DIS ignition system

Voltage waveforms in primary and secondary circuits of a DIS ignition system.
1 – secondary circuit;
2 – cylinder 1 sync pulse;
3 – primary circuit of the ignition coil for cylinders 1 4;
4 – primary circuit of the ignition coil for cylinders 2 3.

Coil on plug (COP) ignition system.

Voltage waveforms in primary and secondary circuits of a COP ignition system
Voltage waveforms in primary and secondary circuits of a COP ignition system
Voltage waveforms in primary and secondary circuits of a COP ignition system

Voltage waveforms in primary and secondary circuits of a COP ignition system.
1 – secondary circuit;
3 – primary circuit.

Characteristic points on the ignition waveform.

Ignition waveforms in the primary and secondary circuits
Ignition waveforms in the primary and secondary circuits

Ignition waveforms in the primary and secondary circuits.
1 – secondary circuit;
3 – primary circuit.
A – Coil primary current is turned on and the magnet field starts to build.
B – Current limiter point.
C – Firing line (Voltage required to ionize air/fuel mixture present in the spark plug gap.
C-D – spark line (Voltage and duration of the actual arc).
D- Spark is extinguished and the residual energy is dissipated in oscillations.

Voltage waveform of multi-spark ignition system

Voltage waveform of multi-spark ignition system.
A – Primary current starts to flow and the magnetic field builds;
B – start of the first spark;
C – Spark is extinguished, the primary current flow is restarted and the magnetic field builds again.
D – start of the second spark;
E – end of the second spark.

Voltage waveform in the primary circuit of a multi-spark ignition system

Voltage waveform in the primary circuit of a multi-spark ignition system (also called multi-strike).

Displaying the high voltage waveform of an ignition system in the Parade mode showing the cylinder sparks in the firing order

Displaying the high voltage waveform of an ignition system in the “Parade” mode showing the cylinder sparks in the firing order. In this case a 4 cylinder engine is displayed.
1 – secondary circuit;
2 – 1st cylinder synchronization.

Displaying the high voltage waveform of an ignition system in the Parade mode showing the cylinder sparks in the firing order

Displaying the high voltage waveform of an ignition system in the “Parade” mode showing the cylinder sparks in the firing order. In this case a 4 cylinder engine is displayed.
1 – secondary circuit;
2 – 1st cylinder synchronization.

Voltage waveform in a secondary circuit of a conventional distributor ignition system

Voltage waveform in a secondary circuit of a conventional distributor ignition system. The capacitor (also sometimes called a condenser and used to extinguish the arc across the point contacts thereby stopping current flow much faster and allowing higher voltage to develop) circuit has high resistance or is open.
A – The breaker points open;
B – The arc across the points is extinguished and normal spark occurs.

Voltage waveform in a primary circuit of a conventional distributor ignition system

Voltage waveform in a primary circuit of a conventional distributor ignition system. The capacitor has high resistance or is open.
A – The breaker points open;
B – The arc across the points is extinguished and normal spark occurs.

Voltage waveform in the secondary circuit of a malfunctioning ignition coil

Voltage waveform in the secondary circuit of a malfunctioning ignition coil. The insulation of the high voltage winding is damaged.

Voltage waveform in the primary circuit of a malfunctioning ignition coil.

Voltage waveform in the primary circuit of a malfunctioning ignition coil. The insulation of the high voltage winding is damaged.

Voltage waveform in the primary circuit of a malfunctioning coil of a multi-spark COP system

Voltage waveform in the primary circuit of a malfunctioning coil of a multi-spark COP system. The insulation of the high voltage winding of the ignition coil is damaged.

Voltage waveform in the secondary circuit of a malfunctioning ignition system

Voltage waveform in the secondary circuit of a malfunctioning ignition system. The resistance of the coil or plug wire is high.

Voltage waveform in the primary circuit of a malfunctioning ignition system

Voltage waveform in the primary circuit of a malfunctioning ignition system. The resistance of the coil or plug wire is high.

Voltage waveform in the secondary circuit of a malfunctioning ignition system

Voltage waveform in the secondary circuit of a malfunctioning ignition system. The spark plug is carbon fouled.

Voltage waveform in the primary circuit of an ignition system

Voltage waveform in the primary circuit of an ignition system. The ignition coil on time is too long.
A – Coil primary current is turned on and the magnet field starts to build.
B – Current limiter point.
B-C – Current limiter line; on time is too long.
C – Firing line (Voltage required to ionize air/fuel mixture present in the spark plug gap.
C-D – spark line (Voltage and duration of the actual arc).
D- Spark is extinguished and the residual energy is dissipated in oscillations.

Voltage waveforms in the secondary circuit of an ignition system with a malfunctioning Ignition Control Module (

Voltage waveforms in the secondary circuit of an ignition system with a malfunctioning Ignition Control Module (ICM). The current limiter in the ICM limits the current too abruptly. This may cause a spark to occur in the secondary circuit too early. This may cause engine damage.

An example of an erroneous early ignition spark, caused by primary current interruption by a faulty ICM.

An example of an erroneous early ignition spark, caused by primary current interruption by a faulty ICM.

Voltage waveforms in the secondary circuit of an ignition system with a malfunctioning Ignition Control Module (ICM).

Voltage waveforms in the secondary circuit of an ignition system with a malfunctioning Ignition Control Module (ICM).

Voltage waveforms in the secondary circuit of an ignition system with a malfunctioning Ignition Control Module (ICM).

Voltage waveforms in the secondary circuit of an ignition system with a malfunctioning Ignition Control Module (ICM).

An example of an ignition system generating additional or misplaced ignition coil firing events due to erroneous signals from the camshaft position sensor.

An example of an ignition system generating additional or misplaced ignition coil firing events due to erroneous signals from the camshaft position sensor.