An electric torch heater (EFU) is used to facilitate starting the engine at ambient temperatures below -5 ˚s to -25 ˚s.

22°С. The device is connected to the engine fuel system and runs on the same fuel as the engine.

Its action is based on the evaporation of fuel in pin glow plugs and the ignition of these vapors with air.

The resulting torch heats the air entering the engine cylinders.

Installation diagram of the electric torch device on the engine

The electric torch device consists of two electric torch candles 3 (Fig. 1) installed in the threaded holes of the engine intake manifolds 2, an electromagnetic fuel valve 6, a thermal relay with additional resistance; a push-button switch, an electromagnetic relay and a control lamp installed in the cab of the car.

On some engine configurations, an electric torch device is not installed.

Scheme of switching on the electric torch device is shown in fig. 2.

Scheme of an electric torch device (EFU)

The electric torch device includes a switch button 4, glow plugs 5, a fuel solenoid valve 6, a control lamp 7, a key switch 8.

Button 4 is a push-button switch.

When button 4 is turned on, glow plugs 5 are turned on. The operating current is supplied to the candles from button 4 through a thermistor in which a thermobimetallic element with contacts is placed.

After 60 - 110 s after heating the candles, the contacts close and voltage is applied to the electro-pneumatic valve 6, which opens access to the fuel to the EFU injectors.

At the same time, voltage is applied to the control lamp 7, which indicates that the system is ready to start the engine.

The starter turns on, and the air-fuel mixture ignited by the candles enters the engine cylinders, warming them up.

When the starter is turned on, the voltage from the lock-switch 8 is also supplied to the plug 85 of the RB relay, which closes the contacts of the plugs Z0 and 87 and supplies voltage to the glow plugs, bypassing the thermistor 3.

This is necessary to maintain the glow of the candles, since when the starter is turned on, the voltage at the battery terminals drops sharply.

After starting the engine, for more stable operation of the engine, the driver can keep the flame in the EFU burning for up to 1 minute by holding button 4 on. It is unacceptable to keep the button on for more than 1 minute after starting the engine.

Maintenance and repair

In the EFU system, glow plugs can fail, which is determined by the control lamp, which will not light up.

If one candle fails, both candles must be replaced at the same time.

If the thermistor 3 fails, the latter must be replaced, as it cannot be repaired.

Relay Test

If relay 2 (P5) fails, the undervoltage to the spark plugs during the engine start-up period will be supplied through thermistor 3, which will lead to non-ignition of the mixture and failure of the EFU. In this case, it is necessary to check relay P5.

The relay is removed from the car and checked according to the diagram shown in fig. 3. The voltage of the power supply must be 24 - 30 V. It is applied to the plug-in terminals 85 and 86 of the relay.

The test lamp checks the voltage on plugs 87 and 88. If the relay is working, the lamp on plug 87 should be on, but not on plug 88.

If the voltage is removed from plugs 85 and 86, then the lamp connected to plug 87 should not light, and the lamp connected to plug 88 should light up. A defective relay must be replaced.

EFU maintenance should be carried out when preparing the engine for winter operation, in connection with the transfer of the engine from summer fuels to winter ones, as well as the need to check the technical parameters of the main EFU products: a flare pin candle and an electromagnetic valve.

  • 1. Remove the EFU from the engine.
  • 2. Parameters for checking the flare pin candle:
  • - At a nominal voltage of 19 V, the current in a minute after switching on should be 11.0 -11.8 A.
  • - The capacity of the spark plug jet should be 440 cm3/min at a supply air pressure of 145 kPa (1.5 kgf/cm2) and a temperature of 20˚± 5 ˚S.
  • 3. Parameters for checking the solenoid valve:
  • - At a nominal voltage of 24 V, the power consumption is no more than 48 W;
  • - Valve actuation (opening) voltage 9-15 V;
  • - Valve release (closing) voltage no more than 6V;
  • - The current consumed by the electromagnet winding, and a response voltage of 12V and an ambient temperature of 20˚С should be 0.8 -1.1 A;
  • - The throughput of the valve is not less than 3.5 l / h. The valve must be sealed at an air pressure of 150 kPa (1.5 kgf/cm2).
  • 4. Blow out the fuel pipes in the system with compressed air at a pressure of 97 kPa (1 kgf/cm2). Air must flow freely in both directions.

In addition, check the tubes for leaks with air at a pressure of 485 kPa (5 kgf/cm2). The inner cavity of the tubes must be clean.

5. If, when checking, the products fit into the requirements of the technical specifications, then they must be re-installed on the engine. If there are deviations in the electrical resistance of the spark plug, replace it.

Torch Pin Candle

If the capacity of the spark plug decreases, unscrew the filter 4 (Fig. 4), remove the dosing insert 5, wash them in unleaded gasoline or ethyl alcohol and blow with compressed air. Then install and re-check the throughput of the candle.

6. Install EFU products on the engine. When installing, connect the fuel line from the injection pump to the solenoid valve, taking into account the direction of the arrow stamped on the valve body.

When installing, lock the flare pin with a lock nut.

Fix the solenoid valve carefully and tighten the fuel line connections securely.

Check and, if necessary, tighten all power supply connections of the EFU, check the reliability of the plug connections.

7. After installing the EFU on the car, bleed the EFU fuel system and check its tightness, for which, with the engine running, press the EFU power button and hold it for 30 seconds after the control light comes on.

Fuel leakage in the system connections is not allowed.

8. Check the health of the electrical circuit of the EFU.

Checking the health of the electrical circuit includes checking the preheating of the spark plugs, heating the spark plug through resistance while the engine is running with the work of the EFU.

Pre-heating of candles is estimated by the strength of the current consumed by the candles, and by the magnitude of the voltage supplied to the candles. The current consumed by the candles is about 23 A, the voltage is about 19 V.

Make sure that the generator set automatically shuts down while the EFU is running.

If the current drawn by the plugs and the voltage supplied to the plug are the same as during the preheat period, then the automatic shutdown of the genset is working properly.



  • 1. Prepare the engine for starting as described above. Set the regulator stop lever to position B with the fuel supply switched on, and turn the governor control lever 3 to the middle position.
  • 2. Press the button for turning on the electric torch device (EFD) and hold it during the entire time the device is in operation. During the heating of the candles, the ammeter in the driver's cab should show a discharge current of about 23 A.
  • 3. After the control lamp lights up (approximately 60 - 110 seconds after pressing the EFU power button), turn on the starter.
  • 4. After starting the engine, until a stable speed is reached, the operation of the electric torch device is allowed, but for a duration of not more than 1 minute.

If the engine does not start, restart in the same sequence. It is recommended to start the next warm-up of the candle 20 - 25 seconds after the end of the previous engine start.

After installing the EFU on the engine or after a long break in operation, bleed the fuel system, for which, with the engine running, press the EFU switch button and hold it for about 30 seconds after the control light comes on.

Failed candles cannot be repaired.