See Figures 1, 2, 3 and 4
All 1986-95 2.3L, 2.8L and 3.0L engines used in the Aerostar utilize one electronic distributor ignition system, which is referred to by two different names: the Thick Film Integrated (TFI-IV) ignition system for 1986-92 models and the Distributor Ignition (DI) system for 1993-95 models. The different names are based entirely upon the years of manufacture. Therefore the ignition system from 1986-92 is known as the TFI-IV system, and the ignition system from 1993-96 is referred to as the DI system. Through-out this section, the ignition system will be referred to as the TFI-IV system.
The 1996 3.0L engine utilizes a distributorless ignition system like that of the 4.0L engine which is covered later in this section.
The ignition system utilizes a controlling computer (known as the EEC-IV computer for 1986-92 models or as the PCM for 1993-96 models), an ignition module (TFI-IV module or Ignition Control Module), a distributor and an ignition coil (E-Core Coil for 1986-92 models/ignition coil for the 1993-96 models).
There are two TFI-IV type sub-systems: Push Start and Computer Controlled Dwell (CCD). The first system features a push-start mode that will allow manual transmission vehicles to be push started. Do not attempt to push start automatic transmission vehicles. The second system, CCD, features EEC-IV controlled ignition coil charge times.
The operation of the universal distributor is accomplished through the Hall effect vane switch assembly, causing the ignition coil to be switched on and off by the EEC-IV and TFI-IV modules. The vane switch is an encapsulated package consisting of a Hall sensor on one side and a permanent magnet on the other side. A rotary vane cup, made of ferrous (magnetic) metal is used to trigger the Hall Effect switch.
When the window of the vane cup is between the magnet and Hall Effect device, a magnetic flux field is completed from the magnet through the Hall Effect device and back to the magnet. As the vane passes through this opening, the flux lines are shunted through the vane and back to the magnet. As the vane passes through this opening, the flux lines are shunted through the vane and back to the magnet. A voltage is produced while the vane passes through the opening. When the vane clears the opening, the window causes the signal to go to zero volts. The signal is then used by the EEC-IV system, along with the signal from the crankshaft position sensor, for crankshaft position sensing and the computation of the desired spark advance based on engine demand and calibration. The conditioned spark advance and voltage distribution is accomplished through a conventional rotor, cap and ignition wires.
The ignition timing is preset at the factory and computer controlled. No attempt should be made to alter the ignition timing from the factory specifications.