Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
MARELLI Electronic Ignition System: Operation
Primary voltage is supplied to the ignition coil by the battery, through the ignition switch. There are no resistors in the Marelli system.
As the distributor shaft rotates, the teeth of the trigger approach and then pass the stator pole in the pick-up coil assembly.
This creates and collapses a magnetic field, causing an electrical signal or impulse. This impulse is fed to the control module. As this signal is received, the control module opens and closes the ignition coil primary circuit.
This causes a high voltage surge in the coil secondary windings, firing the spark plugs.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.