System Description

The Electronic Ignition (EI) high data rate eliminates the need for a distributor by using multiple coil packs. Each coil within the pack fires two spark plugs at the same time. the plugs are paired so that as one fires during the compression stroke, the other fires during the exhaust stroke. the next time the coil is fired, the situation is reversed.

A Crankshaft Position Sensor (CKP) is used to indicate crankshaft speed and position to the Powertrain Control Module (PCM). The PCM uses this information to generate an internal Profile Ignition Pickup (PIP) signal. The calculated spark target is used internally by the PCM as a pulse width modulated digital signal called the Spark Output (SPOUT). The PCM decodes the SPOUT signal and fires the next spark at the commanded spark target. The PIP signal is also used to supply a clean, inverted signal (PIP) for tachometer operation.

The PCM also serves as an electric switch for a coil primary circuit. When the switch closes, current flows and a magnetic field expands around the primary coil. When the switch opens, the field collapses and causes the secondary coil to fire the spark plugs. In addition, an Ignition Diagnostic Monitor (IDM) signal is transmitted on each spark plug firing. This signal communicates information by pulse width modulation.

An external ignition control module is no longer used. This function is built into the PCM.