On some models, the glow plugs remain on for a period after the engine is started, i.e. after the starter is turned off, the glow plugs continue to work for 3 minutes. Glow plugs cannot be interrupted for the first 15 seconds, but they can be disabled later on by:
- pressing the accelerator pedal by more than 11 mm with a duration of pressing more than 2.5 seconds;
- coolant temperature over 60°C.
The control lamp in a combination of devices burns at work of glow plugs. After turning off the lamp, the engine can be started. Voltage is supplied to the glow plugs within a few seconds after the control lamp is turned off. If no attempt is made to start the engine after the lamp has been switched off, the timer cuts off power to the glow plugs to avoid draining the battery and overheating the glow plugs.
Examination
1. Connect a voltmeter between the glow plug supply rail and ground. Turn on the ignition and check that the voltage is supplied to the candles at the appropriate time.
2. At an air temperature of 20°C, the time intervals for applying voltage to the glow plugs should be 5–6 seconds, at which the control lamp is on, and 10 seconds after the control lamp turns off. The burn time of the warning lamp increases at lower temperatures and decreases as the temperature rises.
3. If voltage is applied to the glow plugs, then the relay and wiring are good.
4. To locate a defective glow plug, remove the air intake piping and disconnect the crankcase breather hose from the oil filler neck. Disconnect the main supply wire and connecting bus from the glow plugs.
5. Using the tester (ohmmeter), check the integrity of the glow plugs by checking the resistance between the contact at the top of the plug and the plug body. The resistance of the glow plug is less than 1 ohm; if the tester shows high resistance, the glow plug is faulty.
Tightening torques, Nm
glow plugs | 22 |