7.12. Control systems of the VM 425 LTRU (UAZ-31604) engine


Fig. 305. Electric circuit of control systems of the VM 425 LTRU engine: 1 – solenoid of system of warming up of the cold engine; 2, 3, 4, 5 – glow plugs; 6 – the relay of system of recirculation of the fulfilled gases; 7 – the control unit of system of recirculation of the fulfilled gases; 8 – the sensor of temperature of system of recirculation of the fulfilled gases; 9 – control unit of glow plugs; 10 – relay of inclusion of heating of a fuel-supply line; 11 – fuel-supply line heater; 12 – fuel temperature sensor; 13 – electromagnetic valve of supply of fuel; 14 – the electromagnetic valve of recirculation of the fulfilled gases; 15 – a potentiometer of system of recirculation of the fulfilled gases; 16 – safety lock; 17 – combination of devices; 18 – ignition switch; 19 – relay of inclusion of a starter; 20 – generator; 21 – switch of heating of a fuel-supply line; 22 – assembly block of the relay and safety locks


The electric circuit of control systems of the engine is submitted in fig. 305.

Control unit of glow plugs
The control unit of glow plugs (BOSCH, Germany) is installed on a front board. The block connects to glow plugs the plait of wires which is included in the engine package.

Fig. 306. Control unit of glow plugs: 1 – +12 V; 2 – "weight"; 3 – to the ignition switch 15 plug; 4 – to the ignition switch 50 plug; 5 – to glow plugs; 6 – to a control lamp; S – temperature sensor, "weight"


The scheme of connection, arrangement of contacts and their appointment are shown in fig. 306.
The control unit is not subject to repair. At failure it should be replaced.

The control unit of recirculation of the fulfilled gases
The electronic control unit (VM, Italy) is located on an arm of a board of a front and enters a control system of recirculation of the fulfilled gases and a fuel injection moment advancing corner.
On the engine the retsikulyation valve, a potentiometer of a pedal of management of injection, the regulator of a corner of an advancing of injection and the sensor of temperature of cooling liquid are installed. Everything listed, and also the relay of turning on of the regulator of a corner of an advancing of the moment of injection of fuel which is installed on a front board connect to the control unit of a separate plait of wires.

Fig. 307. The control unit of recirculation of the fulfilled gases: 1 – +12 V; 2 – to temperature sensor; 3 – to an accelerator potentiometer; 4 – to the recirculation relay; 5 – to the recirculation valve; 6 – "weight"


The scheme of connection of the control unit, arrangement of contacts and their appointment are shown in fig. 307.
At failure the control unit needs to be replaced.

Control system of heating of the fuel filter
For heating of diesel fuel and maintenance it in the working range of temperatures in cold season the filter of thin purification of fuel (BOSCH, Germany) has the built-in preheating element of pozistorny type with temperature sensor.
Inclusion of food in an electric chain of system of heating of fuel (see fig. 305) is carried out by the switch of push-button type located on the dashboard. The control lamp is built in the switch.
At a low temperature the sensor of temperature of fuel includes a heating element of the fuel filter and supports him in the included state in the range of temperatures of fuel from (0±3) °C to (8±3) °C.
For unloading of contacts of the switch the heating element joins via the relay located on a front board.
The system of heating of fuel is protected by the fuse 25 A installed in the holder on a plait of wires of a motor compartment.