Unlike the K / KE-Jetronic system, Mono-Jetronic has one single injection valve, which is located centrally above the throttle. The injection valve is electromagnetically controlled in time with the ignition pulses.
Fuel is supplied by the electric and main pumps located in the gas tank through the fuel filter to the injection valve. The pressure regulator maintains the pressure in the fuel system at a constant 1 bar. regardless of the amount of fuel injected.
Air is drawn in by the engine through the air filter and throttle valve. The angle of rotation of the throttle valve is registered by a potentiometer and serves as a measure of the intake air for the control unit, together with the speed.
The control unit regulates the injection duration and thus the amount of injected fuel in accordance with the measured air quantity.
A longer opening of the injection valve injects more fuel. Additional sensors are used to correctly determine the amount of fuel in various engine operating modes.
The sensor-switch for monitoring the extreme positions of the throttle valve is located directly on the throttle shaft. It informs the control unit of the idle position. The control device automatically sets the required speed, while the throttle valve is closed or opened accordingly by the motor. This guarantees a more stable and low idle regardless of the engine temperature.
The coolant inlet temperature sensor measures the engine temperature, which has a major impact on fuel consumption.
The intake duct temperature sensor measures the air temperature. The intake air temperature is taken into account by the control unit to determine the quality of the mixture.
The intake air heater on a carbureted engine prevents fuel from condensing in the intake manifold.
Lambda probe (oxygen sensor) measures the oxygen content of the exhaust gases and sends a corresponding voltage signal to the control unit. Based on this, the control unit changes the fuel/air ratio so that the level of toxic substances in the exhaust gases is kept constant at the lowest level.
The Mono-Jetronic system is virtually maintenance free. only the air filter element should be changed every 30,000 km.
1 - control device
2 - connection plug. For throttle control and idle switch sensor.
3 - throttle damper
4 - connection plug. For injection valve and intake air temperature sensor.
5 - throttle valve controller with idle speed switch
6 - injection valve and intake air temperature sensor
7 - fuel pressure regulator
8 - intake silencer
9 - control valve of the vacuum regulator of the moment of ignition
10 - injection unit
11 - throttle potentiometer
12 - water deflector. For throttle potentiometer
13 - engine electronics control lamp. On the dashboard, a connector for diagnostics: up to 7.88 fuel pump relay, from 8.88 to 7.90 driver's side footwell
14 - lambda probe plug
15 - solenoid valve I, grey. For activated carbon box.
16 - solenoid valve II, black. For activated carbon box
17 - coolant temperature sensor
18 - thermal switch, red, intake air heating
Upper part of the injection unit
1 - bolt, 5 Nm
2 - injection valve holder. With intake air temperature sensor. Measure sensor resistance between outer terminals of connector -18-.
3 - cap. For shipping parts only. delete during installation
4 - O-ring. Always replace
5 - injection valve
6 - bolt, 6 Nm. Coat threads with D6 protectant
7 - the upper part of the injection unit
8 - gaskets. Replace if damaged
9 - bolt, 3 Nm
10 - holder
11 - cover
12 - spring
13 - membrane
14 - pressure regulator
15 - bolt, 6 Nm. Coat the thread with protective agent D6
16 - threaded fitting
17 - gasket
18 - plug. Release clip to remove
Bottom part
1 - stop bolt. For throttle valve. The bolt is fixed at the factory and cannot be rotated
2 - O-ring seal
3 - cork
4 - bolt, 3 Nm
5 - holder
6 - connecting pipe
7 - connecting pipe
8 - throttle potentiometer
9 - the lower part of the injection unit
10 - water deflector
11 - bolt, 6 Nm
12 - throttle control. To stabilize idle. Can only be actuated via the plastic plate using the stop bolt -13-. Loosen and align holder -15- if necessary.
13 - thrust bolt. For throttle position control switch -17-.
14 - throttle damper
15 - holder
16 - protective sleeve
17 - throttle position switch. For stabilization of idling, vacuum adjustment of the ignition, deviation of the fuel supply of forced idling.
18 - bolt, 6 Nm
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