PART A - Engine, Engine Management and Turbocharger

2. Electronic Engine Management - The Ignition System

The Distributor

The distributor - make Marelli - is driven by the auxilliary shaft as on the standard OHC engine.

A Phase sensor, located opposite a cam having two teeth separated at 90° to each other, is fitted inside the distributor. At the passing of a tooth the sensor delivers a signal to the ECU. This signal is similar to the signal supplied by an RPM / TDC-*sensor fitted at the crankshaft pulley.

Both the signal from the distributor and the RPM / TDC-sensor enable the module to identify the phase of each cylinder. This information forms the basis on which the ECU module decides on spark timing and fuel injection.

The Ignition Coil and Ignition Module

The Motorcraft ignition coil and the ignition module (make Marelli) are both fitted to the left fender apron

The ECU sends a Spark-out (SPOUT) signal to the ignition module to trigger an HT pulse by switching the coil primary circuit off.

The Spark Plugs

The Sierra RS Cosworth is fitted with Motorcraft spark plugs AGPR 901 C.

Distributor
1 = Phase sensor
2 = Cam with two teeth

RPM / TDC-Sensor
1 = Tooth on crankshaft pulley
2 = Sensor