The principle of operation of the fuel injection system
An electric fuel pump draws fuel from the tank and delivers it at a pressure of about 2.5 kg/cm2 through the fine filter to the distribution line connected by hoses to each engine cylinder. Installed at the end of the distribution line, the fuel pressure regulator maintains a constant injection pressure and drains excess fuel into the tank, i.e. it circulates the fuel in the system and eliminates the formation of fuel vapors in it.
The amount of injected fuel is determined by the electronic control unit depending on the volume and temperature of the incoming air, the engine speed and engine load, as well as the temperature of the coolant. The main parameter that determines the dosage of fuel is the volume of intake air measured by the air flow meter. The incoming air flow deflects the pressure damper, overcoming the force of the spring, and shifts it to a certain angle, which is converted into electrical voltage by means of a potentiometer. The corresponding electrical signal is transmitted to the control unit, which determines the required amount of fuel at the current moment of engine operation and issues fuel supply time pulses to the solenoid valves of the injectors. Regardless of the position of the intake valves, the injectors simultaneously inject fuel twice for every revolution of the camshaft. If the intake valve is closed, fuel is collected in the space ahead of the valve and is sucked into the cylinder the next time it is opened, along with air.
An additional air supply valve installed in the air duct, made parallel to the throttle valve, brings additional air to the engine during cold start and engine warm-up, which leads to an increase in the engine idle speed.
To facilitate starting a cold engine, an electromagnetic starting nozzle is provided, the opening time of which varies depending on the temperature of the coolant by a thermal time relay.
Adjustment Data
The frequency of rotation of the crankshaft of the engine at idle, rpm: 900-950.
Carbon monoxide content (SO) in exhaust gases, not more than, %: 0.5.
Fuel pump
The electric fuel pump is mounted on the right rear side member of the body.
Opel make/part number: Bosch/90 136 950.
Fuel supply pressure, kg/cm2: 2,3-2.7.
Operating voltage, V: 7-15.
Pump performance at a voltage of 14 V at the terminals, l / h: 60.
Fuel filter
Brand and type: Mann WK 613.
Air filter
Air filter with replaceable dry filter element.
Make and type: Mann C 2668 or GM 90 108 602.
Fuel pressure control
Regulation pressure, kg/cm2: 2,5.
Air flow meter
Brand and catalog number: Bosch 90 136 946.
Resistance when measuring between terminals, Ohm:
- «8» And «9»: 160-300;
- «7» And «5»: 60-1000;
- conclusion «8» pads and terminal «8» meter: 0;
- terminal «9/3» meter and block: 0;
- conclusion «7» pads and terminal «7» meter: 0;
- terminal «5/1» meter and output «5» pads: 0.
Electronic control unit
Brand and catalog number: Bosch 90 122 322.
Resistance, Ohm:
- when measured between plug «1» in the block connector and terminal «1» ignition coils: 0.
- when measured between plug «5» in the block connector and «weight»: 0.
Throttle position sensor
A position type throttle position sensor is mounted on the throttle. The signal from the sensor is used to determine the mode of operation of the engine (idle or full load).
Make and part number, Bosch 90 122 534.
Throttle switch resistance when checking the continuity of the circuit, Ohm:
pregnant «full load»:
- between output «3» pads and terminal «3» switch: 0
- between terminal «9/4» switch and output «3» pads: 0.
pregnant «idle move»:
- between output «2» pads and output «2» switch: 0;
- between terminal «9/4» switch and output «9» pads: 0.
Coolant temperature sensor
Brand and catalog number: Bosch 90 080 939.
Resistance at coolant temperature, kOhm:
- 0°C: 4.8-6.6;
- +20°С: 2.2-2.8;
- +40°C: 1,0-1,4;
- +80°С: 0.23-0.27;
- +100°C: ~0,2.
Resistance when checking the integrity of the circuit, Ohm:
- between pins «10» sensor and pads: 0;
- between output «33» and plug «weight» electronic control unit: 0.
Auxiliary air valve
Brand and catalog number: Bosch 90 136 928.
Valve resistance, Ohm: ~40-75.
Electromagnetic injection nozzles
Brand and catalog number: Bosch 90 128 848.
Resistance, Ohm:
- when measuring between plugs «12» And «5» in the connector of the control unit: 4;
- when measured between plug «12» in the connector of the control unit and nozzle: 15-19;
- when measured between plug «9» in the connector of the control unit and output «8» control unit power relay: 15-19.
Fuel pump relay
Resistance between output «4» pads and terminal «50» relay, Ohm: 0.
Power relay
Resistance, Ohm:
- between output «9» pads and terminal «87» relay: 0;
- between terminal «30» relay and positive battery terminal: 0.
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