Diesel – circuit operation

DIESEL – CIRCUIT OPERATION

Main Relay

Located in the ECM (Z132) box, this relay supplies the power feed to the ECM (Z132). It is controlled via the Ignition Switch (X274) in position II.

Glow Plug Relay (Z135)

The Glow Plug Relay (Z135) takes a feed directly from the battery and, on initialisation via the ECM (Z132), supplies current to each of the six glow plugs (one per cylinder) to aid cold starting. The glow time is controlled via the ECM (Z132) which also monitors the relay and illuminates the glow plug indicator lamp for the duration of the glow time. This relay is relatively large and is located with the main relay next to the ECM (Z132).

Starter Motor Relay

This relay is also ignition key controlled, activated with the key in the ignition III position only. Releasing the key after cranking cuts supply to the relay and switches off the starter motor.

Fuel Pump Relay

The fuel pump relay is pulled in when the starter motor is activated, the earth path provided by the alternator output. When the engine is running, the starter motor is deactivated, supplying an earth path while the generator supplies a feed i.e. a polarity reversal.

ECM (Z132)

If the ECM (Z132) itself is not working, the entire engine management system will cease to operate, i.e. no fuel, tacho reading, etc.