Digital engine management system «1Z» AND «AFN»

The engines use a digital control system, the composition of which is basically the same as that of the injection systems of gasoline engines. The system includes an air flow meter and sensors. the signals of which are sent to the electronic control unit (ECU), which determines the moment of fuel supply and fuel dosage.

Fuel tank. the air filter with a replacement interval every 60,000 km or every year of operation and the fuel filter are similar to the corresponding parts of the diesel engines discussed above.

High pressure fuel pump (injection pump) single-plunger, distributive type, with electronic control does not require any adjustments in operation. If necessary, it is only possible to set the initial fuel injection advance angle.

Brand and type: Bosch VE 4/10 E 2250 R 440 for engine «1Z». Bosch VE 4/10 E 2075 R 638 engine «AFN».

The stroke of the plunger with automatic adjustment of the fuel injection advance angle at the frequency of rotation of the drive shaft:

• 500 rpm: 7.8-10.2 (7,5-11,5) mm;
• 750 rpm: 9.6-11.4 (9,4-11,2) mm;
• 1000 rpm: <= 0.3 (1.0) mm;
• 2125 rpm: 11.6-12.6 (11,5-12,7) mm.

Fuel supply pressure at drive shaft speed:

• 750 rpm: 6.2-6.7 kgf/cm²;
• 2125 rpm: 8.1-9.1 kgf/cm².

Excessive fuel supply at a frequency of rotation of the drive shaft 2125 rpm 40-60 (35-65) cm³/1000 cycles.

Fuel supply at full load at the frequency of rotation of the drive shaft, cm³/1000 cycles:

• 2125 rpm: 54.2-56.8 (53-58);
• 1000 rpm: 55.7-58.3 (54,7-59,5);
• 750 rpm: 37.5-41.5;
• 500 rpm: 40.2-42.8 (39,2-43,8).

Starting fuel supply at a frequency of rotation of the drive shaft 100 rpm: 74 cm³/1000 cycles.


Fuel supply at idle at a drive shaft speed of 500 rpm: 7.2-12.2 (5,2-14,2) cm³/1000 cycles.

Plunger stroke corresponding to the initial fuel injection advance angle when the piston of the 1st cylinder is at TDC of the compression stroke 0.65-0.75 (0,68-0,72) mm.

Adjustment data without brackets. in brackets for verification.

nozzles. Brand and type: Bosch DSLA 150P 294; brand and catalog number of injector bodies: Bosch 0 431 111 997.

Injection start pressure on vehicles produced before June 1992:

• nominal: 246-254 kgf/cm²;
• minimum allowable (when worn): 200 kgf/cm².

On cars produced since July 1992:

• nominal: 190-200 kgf/cm²;
• minimum allowable (when worn): 170 kgf/cm².

Note. If the injection start pressure does not match the specified values, the nozzle must be replaced.

Starter candles. Brand and catalog number: Bosch O 250 202 009.

Air mass meter with pressure damper, with Bosch intake air temperature sensor. Resistance when measured between terminals «1» and «4» meter pads at air temperature, kOhm:

• 0°C: 5.0-6.2;
• 20°C: 2.0-3.0;
• 30°C: 1.6-2.0;
• 50°С: 0.7-0.9:
• 80°C: 0.3-0.5;
• 100°C: 0.175-0.225.

coolant temperature sensor installed in the coolant outlet channel from the cylinder head. The intake air temperature sensor is installed at the intake manifold inlet.

Fuel temperature sensor located on the injection pump. The sensors have a negative temperature coefficient, i.e. their electrical resistance decreases with increasing temperature.

Brake Pedal Position Sensor has a resistance when the pedal is released <10 ohms; when the pedal is depressed ∞.


Vacuum sensorlocated on the mudguard of the right front fender and sends a signal to the ECU about a vacuum in the intake manifold.
Output voltage:

• at a pressure of 0.5 kgf/cm² equal to 1.0 V;
• at 1.0 kgf/cm² - 2.2 V;
• at 1.5 kgf/cm² - 3.6 V;
• at 2.2 kgf/cm² - 4.9 V.

On vehicles produced since August 1994, the vacuum sensor is located in the control unit, which is the reason for the peculiarities of the check operations. Voltage when measured between terminals (on cars produced before August 1994 should be: «1» and «2» approximately equal to 5 V. «2» and «3» =4.5 V (the voltage should decrease when the vacuum pump is running). In the event of a malfunction of the vacuum sensor and the position sensor of the fuel supply control pedal, the electronic control unit as a whole is replaced.

Speed sensor has resistance when measured at the terminals «1» and «2» 1-1.5 kOhm.

Slider Position Sensor injection advance is installed in the high-pressure fuel pump and provides the ECU with information about the fuel injection advance angle.

Injector valve needle stroke sensorinstalled on the injector of the 3rd cylinder and sends a signal to the ECU for the stroke of the needle of the injector valve. Resistance 80-120 Ohm.

Water content sensor in fuel installed in the fuel filter and provides information to the ECU about the water content in the fuel, resistance ∞.

Fuel pedal position sensor since August 1994 located in the control unit and has resistance when measured between terminals «1» and «3» with an unpressed pedal 1.0-1.5 kOhm;


When the pedal is pressed to failure 1.5-2.5 kOhm:

• between pins «2» and «3» 0.8-1.4 kOhm;
• on conclusions «4» and «3» with the pedal released 800-1200 Ohm;
• while the ∞ pedal is depressed.

The speed controller is installed in the injection pump.

Resistance when measured at the terminals «1» and «7» pads of the wire bundle of the mixture control system 400-1100 Ohm.

Fuel start valvehas resistance when measured at the pins «2» l «3» valve pads 14-20 ohm. The clutch pedal position sensor has an output voltage when the pedal is released - 12 V; when the pedal is depressed 0.

Recirculation solenoid valveexhaust gases has a resistance of 14-18 ohms.