Distributor: Description and Operation

Distributor:

DESCRIPTION
the distributor is mounted directly to the camshaft next to the water pump. It directs the spark from the ignition coil to the proper spark plug secondary wire through a rotor. The secondary output connectors in the distributor cap are each connected to an individual spark plug.
The connectors in the cap are arranged for convenience in routing spark plug leads. The corresponding cylinder number is molded into the distributor cap next to each output connector.

OPERATION
The distributor also contains a signal disk and two optical camshaft position sensors that provide signals to the PCM for timing control. One sensor senses 360 equally-spaced slots in the signal disk to provide 720 signals per camshaft revolution for high-resolution timing control. The other optical sensor senses 8 disk slots of variable length, providing a low-resolution signal that tells the PCM which spark plug is being fired. Power for the optical sensors, a system ground, and the two sensors signals are transferred between the PCM and the distributor through a shielded harness connected to the 4-terminal connector on the distributor.

The distributor, ignition system supplies two timing inputs to the PCM, a high resolution signal (360 pulses per one camshaft revolution) and a low resolution signal (8 pulses per one camshaft revolution). The PCM can determine if one of the timing inputs is to being received by comparing the two inputs. If the PCM detects one timing pulse without detecting the other timing pulse, DTC 16 and 36 will set.

The reference signals toggle between 0 and 5 volts as the camshaft turns. Therefore, all open, a short to voltage, a short to ground, or a defective sensor inside the distributor can prevent the voltage from pulsing at the PCM.