Electronic Distributorless Ignition System (EDIS)

EDIS 8 Block Diagram:

The Electronic Distributorless Ignition System (EDIS), consists of a Variable Reluctance Sensor (VRS), an EDIS Module, an EEC IV processor and two 4-tower Coil Packs. This system operates by sending crankshaft position information from the VRS to the EDIS module. The module generates a PIP signal and sends it to the EEC IV processor. The processor responds with a Spark Angle Word (SAW) signal containing advance or retard timing information back to the EDIS module. The module processes VRS and SAW signals and decides which coils to fire. In addition, the module generates an Ignition Diagnostic Monitor (IDM) signal to the processor which is used to indicate a failure mode and also provide a tach output signal.



4.6L-2V Car EDIS System and Component Description

System Description

The 4.6L Electronic Distributorless Ignition System (EDIS) consists of a Variable Reluctance Sensor (VRS) an EDIS Ignition Module an EEC-IV processor and two four-tower Coil Packs.

The Electronic Distributorless Ignition System (EDIS) operates by sending crankshafi position information from the Variable Reluctance Sensor (VRS) to the EDIS module. The module generates a PIP signal and sends it to the EEC-IV processor. The processor responds with a Spark Angle Word (SAW) signal containing advance or retard timing information back to the EDIS module. The module processes the VRS and SAW signals and decides which coils to fire. In addition the module generates an Ignition Diagnostic Monitor (IDM) signal to the processor which is used to indicate a failure mode and also provide a tach output signal.

Component Description

Variable Reluctance Sensor (VRS)

The VRS is a passive electromagnetic device which senses movement of a 36 minus one-tooth wheel located behind the crankshaft pulley. An AC voltage signal is generated which increases with engine rpm and provides engine speed and crankshaft position information to the EDIS module.






Component Description






EDIS Module

The EDIS module is a microprocessor-based device with coil drivers which make decisions about spark timing and coil firing. The module turns the coils on and off at the correct time and in the proper sequence based on information from the VRS and a pulse-width modulated signal (SAW) generated from the EEC-IV processor. The module receives VRS and SAW signals and produces PIP and IDM output signals which are sent to the EEC-IV processor.

EEC-IV Processor






The EEC-IV Processor receives IGN GND and PIP signals from the EDIS module then generates a SAW output signal based upon engine speed load temperature and other sensor information. An IDM signal is received from the EDIS module to determine if an ignition failure mode should be recorded.

Component Description

Coil Pack






The coil is turned on (i.e. coil charging) by the EDIS module then turned of{ firing two spark plugs at once. One is for the cylinder which is to be fired (on compression stroke) and the other goes to the mating cylinder which is on the exhaust stroke. The next time the coil is fired the situation is reversed the next pair of spark plugs will fire according to the engine firing order etc.