Circuit Description

The Electronic Ignition (EI) system uses a waste spark method of spark distribution. In this type of EI system, Crankshaft Position (CKP) sensor is mounted to oil pump near a slotted wheel that is a part of crankshaft pulley. The CKP sensor sends reference pulses to powertrain control module (PCM)/engine control module (ECM). The PCM/ECM then triggers EI system ignition coil. Once PCM/ECM triggers EI system ignition coil, both of connected spark plugs fire at same time. One cylinder is on its compression stroke at same time that other is on exhaust stroke, resulting in lower energy needed to fire spark plug in cylinder on its exhaust stroke.

This leaves remainder of high voltage to be used to fire spark plug in cylinder on its compression stroke. Since CKP sensor is in a fixed position, timing adjustments are not possible or needed.