Ignition Control Module: Description and Operation

PURPOSE
The Thick Film Integrated (TFI) ignition module supplies spark to the distributor through the ignition coil and calculates the duration. It receives its control signal from the Electronic Control Assembly (ECA) Spark Output (SPOUT).

CONSTRUCTION
The ignition control module is a thick film integrated design. The module contains a ceramic substrate thick film assembly and three output drivers mounted on a metal base plate and potted in a plastic housing.

OPERATION
The ignition module has six connector pins at the wiring harness that supplies the following signals:
- Run
- Crank (start)
- Tach (coil)
- PIP (crankshaft position to ECA)
- Spark output (SPOUT from ECA)
- Internal ground from the ECA to the distributor

OPERATION
The TFI module receives the PIP signal from the crankshaft sensor, the CID signal from the camshaft sensor, and Spark Output (SPOUT) signal from the ECA. During normal operation, PIP is sent to the ECA from the crankshaft timing sensor and provides base timing and RPM information. The CID signal provides the ignition control module with the information required to synchronize the ignition coils so that they are fired in proper sequence. The SPOUT signal contains optimum spark timing and dwell time information. Spark angle is determined by the rising edge of SPOUT, while the falling edge of SPOUT controls the coil current "ON" or "DWELL" time. The dwell time is controlled or varied by varying the duty cycle of the SPOUT signal. This feature is called Computer Controlled Dwell (CCD).