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.
Ignition System - Electronic: Operation
On ESA system, the Electronic Control Unit (ECU) is preprogrammed with data for optimum ignition timing under any engine operating condition. Using data from engine sensors (RPM, engine temperature, etc.), the ECU triggers ignition system to provide a spark at precisely the right instant. See Fig 1.
On all other models, as distributor shaft turns reluctor, reluctor teeth (one for each cylinder) pass magnetic pick-up coil assembly. As air gap changes with approach and pass of each reluctor tooth, magnetic field varies creating a signal in pick-up coil assembly.
Ignition module senses this signal and turns ignition coil primary circuit on and off. This causes magnetic field in coil primary winding to collapse, resulting in a voltage surge in secondary winding, which fires spark plugs.
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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.