Experience has shown that cold diesel engines are generally difficult to start. Although direct injection engines are less sensitive than engines with a pre- or swirl chamber, they are still reluctant to transmit the first signs of life to the flywheel even with direct injection without pre-heating, "with a shudder". Therefore, powerful glow plugs heat up the compressed air in the cylinder during the cold start stage and thus speed up the ignition process. Direct injection engines, like those in the Focus, start "politely" in mild winters, but they do so with difficulty in freezing temperatures. Thanks to the pre-heating system, you can happily dispense with the previously obligatory "thoughtful minute" of diesel engines. The pre-heating system will put your Focus in a good mood as soon as the ignition key supplies current to the system. When the cold engine shows the first signs of life, the glow plugs will continue to heat for about two more minutes. There are good reasons for this: engine operating comfort increases, noise is reduced, and exhaust gases become significantly cleaner than in the absence of an external heating source.
As a rule, all these helpful assistants do their work unnoticed behind the scenes: the pre-glow system light in the combination instrument panel glows, if at all, for only a few seconds. The system is divided into a control unit and a relay unit. The control unit is located in the engine compartment and regulates the duration of heating by the glow plugs. In order to ensure that the glow plugs always have full energy, the "currents" are controlled by a relay in the auxiliary fuse box. It occupies slot No.9 and receives voltage through fuse No.5.
Each cylinder is heated by a separate spark plug. The glow plugs in the Focus are very compact - they work without temperature regulation. This is not a disadvantage, since the fresh air sucked in does not allow the spark plugs to burn - the maximum temperature is limited to about 1050°C.
System failures are automatically collected by an electronic storage device - information in it can only be read and erased in a company workshop.
