Engine management system operation

ENGINE MANAGEMENT SYSTEM OPERATION

PGM-Fi is a sequential multiport fuel injection engine management system which utilises one engine control module (ECM) to control both the fuel injection and ignition systems.

Engine Control Module (ECM)

The ECM receives inputs from various sensors on and around the engine and provides the correct timing to suit the prevailing conditions.

The ECM receives inputs from the following sensors: TDC/CKP/CYP sensors (which are all an integral part of the distributor) Manifold air pressure (MAP) sensor Engine coolant temperature (ECT) sensor Intake air temperature (IAT) sensor Oxygen sensor (O2S) Throttle position (TP) sensor Vehicle speed sensor (VSS) Starter signal Alternator FR signal Shift position signal Battery voltage

These inputs are processed by the ECM into five control channels: Injection timing and duration Electronic idle control Ignition timing and control ECM back-up function All other control functions

The output of these control channels controls the operation of the following units: Injectors PGM-Fi main relay Malfunction indicator lamp (MIL) Idle air control (IAC) valve Ignition control module (ICM) Purge cut-off solenoid valve Lock-up control solenoid valve Diagnostic connector

A malfunction indicator lamp (MIL) which is incorporated in the instrument panel will be continually illuminated to inform the driver of a PGM-Fi malfunction.

NOTE: The malfunction indicator lamp always illuminates for two seconds after the ignition is switched on to check the light circuit.

The MIL will be extinguished when the ignition is switched off, however, the memory for the relevant fault will not be cancelled.

Fault codes stored by the ECM can be interrogated by connection of TestBook to the diagnostic connector.

After rectifying a fault, disconnect the ECM battery supply by removing fuse J (7.5A) from the engine compartment fusebox for 10 seconds to reset the ECM memory.

Injection timing and duration

Fuel injection throughout the speed range of the engine is controlled by the ECM, which contains memories for the basic injector opening times at various engine speeds and manifold pressures. The basic injector opening time after being read out from the memory, is further modified by signals sent from various sensors on and around the engine to obtain the final injector opening times.

Fuel is delivered by the pump to the fuel rail where fuel pressure is controlled by a pressure regulator valve. The fuel rail supplies fuel to the injectors which are operated by the ECM. The ECM processes information from the following sources:

Crank position (CKP), Cylinder position (CYP) and Top dead centre (TDC) sensors which are located within the distributor. The CKP sensor determines timing for fuel injection and ignition of each cylinder and also detects engine speed. The CYP sensor detects the position of No. 1 cylinder for sequential fuel injection to each cylinder. The TDC sensor determines initial ignition timing and is used by the ECM as a back-up should the crank/cylinder sensor produce abnormal signals.

Manifold air pressure sensor, converts manifold air pressure readings into voltages and sends them to the ECM where they are used to determine engine load.