The ignition system on the Single Point Fuel Injection (SPFI) system is composed of a battery, an ignition coil, a distributor, spark plugs, an SPFI control unit and wires. The crank angle sensor built into the distributor detects the reference crank angle and the positioned crank angle.

Electronic signal of both angles is transmitted to SPFI control unit which is used in common with fuel injection system. The SPFI control unit calculates the spark advance angle and determines the spark timing.

The electronic signal of spark timing determined by control unit is transmitted to the power transistor where it makes the primary circuit to ignition coil, whereby high voltage current is generated in the secondary circuit.

The high voltage of secondary circuit is distributed to the spark plug of each cylinder and discharged there. The spark advance angle is calculated from the following 3 factors: engine speed compensation, advance when starting the engine, and advance in all driving conditions except starting the engine, after engine speed exceeds the present value. See Figure .

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.

Safety Warning

Spark Control System: Description: SPFI

Use the Manual With the Right Hardware

When to See a Mechanic