Power supply system. BMW the 5th E28/E34 series (from 1981 to 1993 of release)
Repair of BMW E28 and series E34 from 1981 to 1993
1. Cars of the BMW brand of 5-series
2. Engine
3. Cooling system
4. Power supply system
4.1. General information
4.2. Pressure removal in system of injection of fuel
4.3. Check of pressure of fuel / fuel pump
4.4. Removal and installation of the fuel pump, intermediate pump and fuel level sensor
4.5. Repair and replacement of fuel lines and connectors
4.6. Removal and installation of a fuel tank
4.7. General information about cleaning and repair of a fuel tank
4.8. Removal and air purifier installation
4.9. Check, adjustment and replacement of a cable of an accelerator
4.10. General information about the carburetor
4.11. Removal and carburetor installation
4.12. Cleaning and carburetor adjustment
4.13. General information about fuel injection
4.14. Systems of injection of fuel
4.15. Check of functioning of system of injection of fuel
4.16. Functioning check, removal and installation of a measuring instrument of a stream of air
4.17. Functioning check, removal and installation of the case of a throttle
4.18. Check of functioning and replacement of a regulator of pressure of fuel
4.19. Check of functioning and replacement of an injector of cold start and temperature switch
4.20. Check of functioning and replacement of fuel injectors
4.21. Functioning check, adjustment and replacement of the air valve of stabilization of idling
4.22. Search of malfunctions of system of injection of fuel
4.23. Diagnostics of malfunctions of a power supply system
5. Ignition system
6. Control systems of the engine and decrease in toxicity of the fulfilled gases
7. System of production of the fulfilled gases
8. Coupling
9. Manual box of gear shifting (RKPP) and automatic transmission (AT)
10. Transmission line
11. Steering and suspension bracket
12. Brake system
13. Body
14. Control body sizes
15. Heater and air conditioner
16. System of onboard electric equipment
17. Routine maintenance of the car
18. Size table and adjusting data
19. Schematic electric circuits
20. Governing bodies and operation receptions
21. System of onboard diagnostics - a principle of functioning and codes of malfunctions


4. Power supply system

General information

All engines except for early models (518), are equipped with electronic system of injection of fuel.

Early models 518 are equipped with Solex carburetors. It is applied or the Solex 2B4 carburetor (early models), or 2 (late models). The mechanical fuel pump is put in action by an ekstsentrikovy cam of a camshaft.

Models with injection of fuel are equipped or fuel system of injection of L-Jetronic, or Motronic. Since 1988 of model with injection of fuel are equipped with Motronic system applied so far - this system easy to distinguish from earlier on lack of an injector of cold start. The electric fuel pump is located under a back of the car or in a fuel tank. The relay of the fuel pump on Motronic system turns on low level of a signal from the Motronic (ECV) control unit. The fuel pump after inclusion of ignition turns on for some seconds and further works only at operation of the engine.

System of an admission of air

The system of an admission of air consists of the case of the air filter, a measuring instrument of a stream of air and the throttle case (model with injection) and the inlet pipeline. In this Chapter all components, except for the inlet pipeline are considered; for data on removal and installation of the inlet pipeline address to the Part the Repair work which is carried out without extraction of the engine from the car.

The throttle valve in the case of a throttle is put in action by an accelerator cable. By pressing an accelerator pedal the butterfly valve opens and the air stream in system increases.

In systems of injection of fuel the zaslonka in the batcher of air opens more widely and the stream of air increases. The sensor of provision of the throttle, established on a zaslonka axis, measures a corner of provision of a zaslonka (as far as it opens) and will transform this size to tension which is transferred in the computer.

Fuel system

On carburetor models the fuel pump submits to the carburetor fuel under pressure.

The needle valve in the poplavkovy chamber supports constant level of fuel. On channels of return of fuel system surplus of fuel arrives back in a fuel tank.

On models with fuel injection the electric fuel pump submits fuel to the highway with constant pressure. The electric fuel pump on late models is located in a fuel tank or near a tank on early models. Early models are also equipped with the intermediate pump located in a fuel tank. The intermediate pump operates as auxiliary more powerful main pump at creation of necessary pressure. Pressure in fuel system the regulator of pressure of fuel operates. The fuel system also has a damper of pulsations of pressure close to the fuel filter. The damper reduces the pulsations of pressure caused by operation of the fuel pump and opening - closing by an injector. The amount of fuel injected into ports of an admission precisely is defined by the electronic Control unit (ECV or the computer). Some late models 5 of a Series have the device of cooling of fuel in the return line.

Electronic control system (system of injection of fuel)

Except serial opening of injectors as it is described above, the electronic control unit carries out some other the tasks connected with control of fuel system and system of release. The block carries out these tasks, using data which arrive from a large number of the information sensors located in an impellent compartment, comparing these data with information in memory and changing power setting, operating various devices. The majority of works on diagnostics of malfunctions and to repair of an electronic control system due to the need in the special equipment are outside of possibilities of the mechanic - the fan. Additional data and procedures of testing of components of system of release (the sensor of concentration of oxygen, the sensor of temperature of a cooler, EVAP system and others) are given in Head of the Control system by the engine and decrease in toxicity of the fulfilled gases.

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4.1. General information