The distributorless ignition system (DIS) of the 1,1/1,3 litre HCS engines in the Ford range comprises a powertrain control module and a number of sensors. The sensors supply the powertrain control module with input signals which relate to engine operating conditions and this allows the powertrain control module to accurately control spark timing.

Powertrain Control Module (PCM)

There are two different types of powertrain control module used and these are not interchangeable. One meets 15.04 emission regulations and the other later version meets new EEC emission regulations.

Both DIS ignition systems are very similar in appearance and operation with the EEC emission version having one additional sensor which measures intake air temperature (ACT).

Crankshaft Position Sensor (CPS)

The crankshaft position sensor is an inductive pulse generator which scans 36-1 cast protrusions on the flywheel. Minus one means that one of the protrusions is missing. This gap is located at 90º before top dead center and is used by the powertrain control module as a reference mark for crankshaft position. The crankshaft position sensor sends an alternating voltage signal to the powertrain control module which is used to determine engine speed and ignition timing.

Intake Air Temperature Sensor (ACT)

The intake air temperature sensor fitted to New EEC emission variants is a temperature dependent resistor which has a negative temperature coefficient, i.e. it's resistance changes inversely with respect to temperature.

The intake air temperature sensor is supplied with a reference voltage by the powertrain control module and the resultant voltage signal from the intake air temperature sensor is assigned to a corresponding intake air temperature.

Engine Coolant Temperature Sensor (ECT)

The engine coolant temperature sensor is a temperature dependent resistor which has a negative temperature coefficient, i.e. it's resistance changes inversely with respect to temperature.

The engine coolant temperature sensor is supplied with a reference voltage by the powertrain control module and the resultant voltage signal from the engine coolant temperature sensor is assigned to a corresponding engine coolant temperature.

Manifold Absolute Pressure Sensor (MAP)

Both powertrain control modules have an integral manifold absolute pressure sensor. The manifold absolute pressure sensor input connection on the powertrain control module is connected via a fuel trap to the inlet manifold.

The manifold absolute pressure sensor is an electronic device containing a pressure sensitive component which changes the frequency of an oscillator. The output frequency is therefore proportional to the applied vacuum.

WARNING:
With all ignition systems very high voltages are produced and all safety precautions must be taken.

The Fuel Charging System

The fuel injection equipment fitted to the HCS engine comprises a throttle body fuel injection unit which is fitted with a fuel pressure regulator and a fuel injector.

Fuel Pressure Regulator

The fuel pressure regulator is a spring loaded diaphragm unit fitted directly into the throttle body fuel injection unit. The fuel pressure regulator is designed to maintain a constant fuel pressure within the throttle body fuel injection unit regardless of the amount of fuel being injected. Excess fuel is returned to the fuel tank.

Fuel Injector

The fuel injector is of the side feed type and is surrounded by fuel when mounted in the throttle body fuel injection unit. The fuel injector is retained by two bolts and sealed by means of two O-ring seals.

The fuel injector is activated by the powertrain control module which modifies fuelling by adjusting the fuel injector pulse width according to engine operating conditions.

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