Electronic Ignition (EI) System

The EI system (also known as distributorless, direct, or computer-controlled coil ignition system) was actually introduced in the mid 1980s, but really became popular in the early 1990s. Tune-up intervals on EI systems vary, but some manufacturers boast up to 100,000 miles (≈160,000 km). The advantages over the DI system are the elimination of a mechanical distributor, higher firing voltage, better timed spark, and a more efficient running engine. One example of an EI system is the coil-on-plug (COP) system. The COP unit, mounted directly on the spark plug, is controlled by the PCM. The PCM uses sensor input to precisely control the timing. The primary and secondary circuits are inside the coil-on-plug. Eliminating the distributor and coil/spark plug wires allows the COP system to operate very efficiently. The ignition module may also be integrated into the coil.