Mercedes W124

since 1985-1995 of release

Repair and car operation

W124 Mercedes
+ Governing bodies and control devices
+ 2. Maintenance (diesel engines)
+ 4. Repair of 6-cylinder petrol SOHC engines
+ 5. Repair of 6-cylinder petrol DOHC engines
+ 6. Repair of the diesel engine established in the car
+ 7. Major maintenance of engines
- 10. System of injection of BOSCH CIS-E fuel (KE-JETRONIC)
   10.2. General information
   + 10.3. Accelerator cable
   10.4. Air filter
   10.5. Casing of the air filter
   10.6. Fuel filter
   10.7. Pressure accumulator
   10.8. Fuel level sensor
   10.9. Fuel pump
   10.10. Fuel tank
   10.11. Throttle case
   10.12. Inlet collector
   + 10.13. Elements of system of injection of KE-JETRONIC fuel
   10.14. Pressure removal in fuel system
   10.15. Adjustment of turns of idling and the contents WITH in exhaust gases
+ 11. System of injection of BOSCH HFM fuel
+ 12. Fuel system of diesel engines
+ 13. Fuel system of diesel engines
+ 15. System of ignition of 4-cylinder petrol engines
+ 16. System of ignition of four-cylinder petrol engines
+ 19. Mechanical transmission
+ 20. Automatic transmission

10.2. General information


The system of injection of BOSCH KE JETRONIC fuel is the modified option of mechanical system of injection of K JETRONIC fuel which was established on earlier models.

The fuel tank on the Sedan models and the Compartment is established vertically behind a back of a back seat. On the Versatile person models the fuel tank is established horizontally under a trunk floor. The fuel level sensor fastens in the top part of a fuel tank and can be replaced without removal of a fuel tank.

The electric fuel pump of roller type is established under the bottom in a back part of the car. Cooling of the fuel pump is made by fuel proceeding through it. The fuel pump has the unidirectional valve which supports pressure in fuel system even after engine switching off. Also the pump has perepuskny the valve which limits the maximum pressure in fuel system.

Between the fuel pump and submitting fuel hose the accumulator of pressure which supports pressure in fuel system after engine switching off is established. After the accumulator of pressure reduces fluctuation of pressure of fuel which arises in fuel system at work of fuel nozzles.

The fuel filter of cartridge type is established about the pressure accumulator behind the fuel pump.

Measurement of amount of fuel is made by the distributor which mechanically regulates size of amount of the fuel submitted to fuel nozzles on the basis of a deviation of the sensor of measurement of a stream of air. The structure of a mix is regulated by dynamically executive mechanism of pressure электрогидрав the lichesky shock-absorber at continuous management of the electronic control device (ECU). Management of the ECU block is made on the basis of signals of the sensors located on the engine and about it. Continuous dynamic correction of a fuel mix improves operation of the engine, reduces consumption of fuel and quantity of harmful substances in exhaust gases. Besides, the differential valve of pressure in a distributive element operation of it modes provides continuous supply of fuel on all.

Start of the cold engine is facilitated by the valve of cold start and the auxiliary air device. The valve of cold start is electricly the operated fuel nozzle established in an inlet collector and spraying in addition fuel in air, arriving in the engine. The switch of a mode of starting supply of fuel (the thermotime sensor) operates time during which the valve of cold start remains open. The auxiliary air device is a valve which allows air to bypass a butterfly valve therefore idling turns increase. The bimetallic plate and a spiral of a heater operate size and time of opening of the valve. The auxiliary air device works only at start of the cold engine.

On later models the rotary executive mechanism is established. This knot replaces the auxiliary air device and copes the ECU block therefore turns of idling are stabilized on all operational modes, including a mode of the accelerated idling in the course of warming up and management of idling turns under loading.

Models with the catalyst have feedback which on the basis of a signal of the sensor of oxygen regulates a ratio of a fuel mix.


The fuel system is under constant pressure, even after engine switching off therefore at carrying out any works on fuel system it is necessary to remove pressure.

For prevention of possibility of casual short circuits of an electric chain and damage of electronic components of system of injection of fuel always remove a weight wire from the accumulator.


Gasoline extremely fire - also is explosive, therefore it is necessary to show care at work on any part of fuel system.

Works on fuel system are necessary for making in well aired room for what it is possible to open all windows and doors for draft creation.

At work on fuel system do not use open fire, electric welding and tools, at work with which sparks can be formed. Check that in close proximity to a workplace there is a charged fire extinguisher.

For protection of eyes against fuel hit in them use points. At fuel hit on skin wash out this place a plentiful quantity of water.

The capacity in which there was a fuel, contains pairs of fuel and is potentially explosive.

At work with fuel system observe purity as the dirt which has got to channels of fuel system, can block them that will break normal operation of the engine.