Variations in pre-heating period

Rapid type heater plug

NOTE The heater plug reaches a temperature of 850°C. It contains a resistive spiral in Alferon which has a high resistance and Nickel which has a low resistance, welded by laser. The outer casing is made of metal.

Variations in pre-heating period

1. A. Period with heater plugs warning light on.
2. B. Range in which the warning light goes out and pre-heating is taking place (shaded area).
3. C. Period in which pre-heating is taking place and warning light is off. This stage which lasts 15 - 20 secs is counted starting when the warning light goes out.
4. D. Post-heating period with heater plugs on and warning light off. This stage which lasts 15 - 20 secs is counted from when the starting stage is over and the engine is running.
5. E. Period with warning light off and pre-heating over.

HEATER PLUGS CONTROL UNIT

This is an electronic device which controls a relay for the current to pass automatically between terminals 1 and 5.

The control unit is rendered operational by the following connections:

1. 1. large section black cable, from the battery
2. 2. black earth cable
3. 3. twin orange supply cable from the control unit: one coming from terminal 15/54 of the ignition switch; the other goes to the engine cut out device on the injection pump
4. 4. red/black cable (instant starting control); coming from terminal 50 of the ignition switch
5. 5. brown cable: to the heater plugs
6. 6. brown cable to the heater plugs warning light (contact 6, connector E) of the instrument panel