Ignition system

This ignition system does not use a breaker-distributor and a coil. Instead, a crankshaft position sensor is used, which sends a signal to the engine control unit (ECM). After that, the ECM generates the ignition distribution (EST) and starts the ignition coil spark directly.

This type of ignition system without a distributor breaker works according to the method «excess spark». Cylinders are paired with opposite (1-4 or 2-3). The spark occurs simultaneously in the cylinder in which the piston is in the compression phase and in the cylinder in the exhaust phase. A cylinder in the exhaust phase requires very little energy to spark a spark plug. The rest of the energy is used by the spark plug in the cylinder during the compression phase. The ignition coil cannot be repaired, so the entire assembly must be replaced.

These systems use the EST signal from the ECM to control the electronic ignition system. The ECM uses the following data:

• engine load (manifold or vacuum pressure);
• atmospheric (barometric) pressure;
• engine temperature;
• supply air temperature;
• crankshaft position;
• engine speed (rpm).