Ignition System - DURA-Spark III: Description

The ignition portion of the EEC III system is referred to as Dura-Spark III. It is a solid state system, which provides power switching of the ignition coil. Dura-Spark III input signals are controlled by the EEC system.

Unlike Dura-Spark II, the Dura-Spark III distributor has no centrifugal or vacuum advance, armature (reluctor) or stator (pick-up coil). See Figure The functions of these components are performed by the EEC module. All engines with EEC III use this except the 3.8L V6 engine, which uses a modified Dura-Spark II distributor. Secondary wires and spark plugs are the same in Dura-Spark II and III systems.

Although control modules appear similar, they must not be interchanged. Dura-Spark III control modules have no Purple wire, and can also be identified by a Brown grommet. Dura-Spark II modules have a Blue grommet. Universal Ignition Modules (UIM) used in Dura-Spark II systems have a Yellow grommet and a third connector.

Ignition timing is determined by the EEC control module based on information received from crankshaft position (CP) sensor and other engine sensors. These sensors feed information to the EEC III system Electronic Control Assembly (ECA) through a special 32-pin connector. For further information on these sensors and the electronic control assembly, see appropriate Electronic Engine Control III article in COMPUTER ENGINE CONTROL section listed below.

• 5.0L/5.8L EEC III TESTING
• EEC III THEORY/OPERATION

Unlike conventional distributors that are restricted to approximately 20° advance, the EEC system permits up to 50° distributor advance. Both distributor cap and rotor have upper and lower electrode levels.

As the rotor turns, one of the high voltage electrode pick-up arms is aligned with one arm of the distributor cap center electrode plate. This allows high voltage to pass from the center plate arms through the rotor, distributor cap, and spark plug wire to the appropriate spark plug.