Ignition off

The central control unit in your Focus can be damaged if you crank the engine with the starter while the ignition wires are disconnected. Therefore, before carrying out certain work, first turn off the ignition.

Interrupt the power supply to the ignition module.

Are the wire connectors and multi-pin connectors securely connected to the ignition coil and control unit? Loose ignition wires can rise slightly in the terminal sleeves due to the heating of the air trapped in them, and as a result, this will lead to misfiring. Disconnected spark plug wires can cause surface leakage currents and uncontrolled sparking.

Check the ignition coil housing for cracks or burns caused by sparks.



Are the spark plug terminals making good contact? They must not be oxidized.

Check the ignition wires, the insulation should not be worn or frayed. Wires with traces of scuffs or melting should be replaced immediately. With a defective ignition wire, a spark can jump off before the spark plugs (path of least resistance!) - this is what you hear from the clicking sounds in the engine compartment.

Remove salt and lime deposits from ignition wires.