Direct Ignition System (Dis)

The operation of DIS is quite similar to operation of the C(3)I system. Systems consist of 2 ignition coils, ignition control module (located under coil pack), a camshaft position sensor, 2 Hall Effect crankshaft position sensors, necessary wiring, and the ignition control and fuel metering portion of the PCM.

Spark is timed by a signal sent from a crankshaft position sensor mounted through side of engine block instead of from a crankshaft position sensor mounted at crankshaft pulley (such as C(3)I). This signal is received by PCM (through ignition control module) and is used to trigger each coil at the proper time. See appropriate CRANKSHAFT POSITION SENSOR under INPUT DEVICES  . As with the C(3)I system, each cylinder is fired consecutively with the cylinder opposite it in the firing order. Cylinder No. 1 is paired with No. 4 and cylinder No. 2 is paired with No. 3. Each pair of cylinders is fired by its own ignition coil.

Crankshaft position sensor is mounted under the intake manifold. The crankshaft position sensor protrudes through the side of engine block to within .05" (1.3 mm) of an internally-mounted crankshaft reluctor ring. Sensor position is not adjustable.

The reluctor is a piece of metal, cast with the crankshaft. Reluctor has 7 slots machined into it, 6 of which are equally spaced (60 degrees apart). The seventh slot is spaced about 10 degrees from one of the other slots and generates a synchronization pulse signal. As crankshaft rotates, notches in reluctor ring change the magnetic field at the tip of position sensor. This creates an induced AC voltage signal in the sensor windings, resulting in RPM reference signals which are sent to PCM by the ignition control module. This allows PCM to compute crankshaft position and RPM.