Electronic DISTRIBUTORLESS Ignition System (EDIS)

System is used on 4.0L engines and consists of a Variable Reluctance Sensor (VRS), an EDIS ignition module, an ECA and one 6-tower coil pack.

During system operation, EDIS ignition module receives crankshaft position information from VRS. In turn, EDIS ignition module generates a Profile Ignition Pick-Up (PIP) signal and sends it to ECA. The ECA responds with a Spark Angle Word (SAW) signal containing advance or retard timing information, which it sends to EDIS module. The EDIS ignition module then processes VRS and SAW signals to decide which coils to fire. In addition, EDIS ignition module generates an Ignition Diagnostic Monitor (IDM) signal and sends it to ECA, which uses it during failure mode to provide a tach output signal.

The EDIS ignition module is a microprocessor and makes decisions about spark timing and coil firing. The EDIS ignition module turns coils on and off at correct times and in proper sequence, based on VRS and SAW signals. The EDIS ignition module, upon receiving VRS and SAW signals, produces PIP and IDM output signals and sends these signals to ECA.

The ECA receives IGN GND and PIP signals from EDIS ignition module, and then generates a SAW output signal, based upon fuel, air and other sensor information. ECA also receives an IDM signal from EDIS ignition module to determine if a failure mode should be recorded.

The coil pack receives active low signals from EDIS ignition module and fires 2 spark plugs at a time. One plug is for cylinder which is to be fired (on compression stroke) and other goes to mating cylinder (on exhaust stroke). The next time coil is fired, situation is reversed. Coils are fired according to engine firing order.