Location of preheating components in car

The preheating control system brings the temperature of the prechambers up to a temperature to permit self-ignition, and it consists of the following components:

• a preheating electronic control unit located in the engine compartment;
• four rapid glow plugs;
• a wait-to-start warning light located on the instrument panel.

Location of preheating components in car

1. Fuel filter
2. Fuel outlet
3. Fuel inlet
4. Preheating control unit
5. Glow plugs
6. Manual device for injection advance when cold

PREHEATING ELECTRONIC CONTROL UNIT

The purpose of the electronic control unit in the engine compartment is to carry out the following:

• deliver current from the battery to the spark plugs for a length of time varying in accordance with the engine compartment temperature, before starting. This temperature is recorded by a negative temperature coefficient (NTC) gauge located in the electronic control unit;
• keep the wait-to-start warning light on for a period of time depending on the engine compartment temperature (from 1.5 to 4.5 seconds at a temperature of 70°C, from 20 to 27 seconds at a temperature of -20°C);
• ensure for a so-called "distraction" time (about 20 seconds) that the glow plugs remain supplied if the engine does not start, and if the engine does start, to interrupt the delivery of current at the end of the distraction time;
• if one of the glow plugs or the current cable accidentally shorts to earth, immediately stop the delivery of current.