Ignition System: Description and Operation

The Distributor Ignition (DI) system features a camshaft-driven distributor, which uses no centrifugal or vacuum advance. The distributor has a die cast base which incorporates a Hall effect stator assembly. This system also features a computer-controlled dwell ignition.

Initial timing adjustments are not required unless the distributor has been moved from its factory set position.

Hall Effect Device:

The distributor operates by using a Hall effect vane switch assembly, which causes the ignition coil to be switched OFF and ON. The vane switch is an encapsulated package consisting of a Hall effect sensor on one side and a permanent magnet on the other side.

Vane Cup:

Hall Effect Device Response To Vane:

When the window of the vane cup is between the permanent magnet and the Hall sensor, a magnetic flux field is completed from the permanent magnet through the Hall sensor and back to the magnet.

Figure 7 - Magnetic Flux Field:

When a vane clears the opening, the window edge causes the signal to go to zero volts. The signal is then used for sensing crankshaft position and computing the desired spark advance, based on engine demand and calibration. The voltage distribution is accomplished through a conventional rotor, cap and distributor to spark plug wires.

The ignition system uses two sensors that provide information to the Powertrain Control Module (PCM). The two sensors are:
- Crankshaft Position (CKP) sensor.
- Camshaft Position (CMP) sensor.