DISTRIBUTORLESS Ignition Systems (1.9L & 4.6L)
The Electronic Distributorless Ignition System (EDIS) consists of a Variable Reluctance Sensor (VRS), EDIS Ignition Module and one 4-tower coil pack (2 coil packs on 4.6L).
The EDIS operates by sending crankshaft position information from VRS to EDIS module. The module generates a Profile Ignition Pickup (PIP) signal and sends it to ECA.
The ECA responds with a Spark Angle Word (SAW), processes the VRS and SAW signals and decides which coils to fire. Also, the module generates an Ignition Diagnostic Monitor (IDM) signal to ECA, which is used to provide a tach output signal and indicate a failure mode if detected.
The VRS is an electromagnetic device that senses movement of a 35 tooth wheel, located behind the crankshaft pulley. Each tooth is positioned in 10 degree increments with an empty slot (missing tooth) located 90 degrees BTDC. The detection of the missing tooth is what enables the ECA to identify crankshaft position and initiate correct firing order.
The EDIS module is a microprocessor with coil drivers. EDIS Module strategy controls spark timing and coil firing. The module turns coils on and off at the correct time and in proper sequence, based on information from VRS and a pulse width modulated signal (SAW) generated from ECA. The module receives VRS and SAW signals and produces PIP and IDM output signals, which are sent to ECA.
The ECA receives ignition ground and PIP signals from the EDIS module, and then generates a SAW output signal based on engine speed, load, temperature and other sensor information. An IDM signal is received from EDIS module to determine if an ignition failure mode should be recorded.
The coil is turned on (coil charging) by EDIS module, and then turned off, firing 2 spark plugs at once. One plug is fired on the compression stroke; the other plug fires the mating cylinder, which is on the exhaust stroke. On the next cycle, firing strategy is reversed.