E30 series BMW 3

since 1983-1994 of release

Repair and car operation

+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engine
+ 4. Cooling system
+ 5. Heating and ventilation
- 6. Fuel system
   6.2. Specifications
   6.3. Check of system of injection
   6.4. Measuring instrument of a stream of air
   6.5. Throttle branch pipe
   6.6. Regulator of pressure of fuel
   6.7. Nozzle of start-up of the cold engine and thermotimer
   6.8. Check and replacement of nozzles
   6.9. Air proof-reader of idling
   6.10. Order of a decompression of fuel system
   6.11. Check of pressure of fuel
   6.12. The fuel pump, the pump of pumping and the fuel level sensor in a tank
   6.13. Gasoline pipe lines and union
   6.14. Fuel tank
   6.15. Air filter
   6.16. Cable of a drive of a butterfly valve
   6.17. Carburetor
+ 7. Exhaust system
+ 8. Transmissions
+ 9. Coupling
+ 10. Brake system
+ 11. Running gear
+ 12. Body
+ 13. Electric equipment
+ 14. Good advice


6. Fuel system

6.1. Introduction


Considered cars are equipped with system of injection of fuel, except models 316 on which Solex 2B4 carburetors (cars of early release) and Solex 2BE (later release) are established. The fuel pump of carburetor engines mechanical, with a kulachkovy drive from a cam-shaft.

System of injection of the L-Jetronic or Motronic type. Since 1988 cars are equipped with advanced system Motronic in which there is no nozzle for start-up of the cold engine. The electric fuel pump is mounted or in a back part of the car, on the body bottom (on early models), or in a fuel tank. In Motronic system of the relay of injection works from a signal from the control unit (ECU block). At ignition inclusion the fuel pump works within several seconds and is disconnected only after a full stop of the engine. On early models the pump of pumping of the low pressure, mounted in a fuel tank and included consistently with the main pump is provided. The main pump provides maintenance of necessary pressure of fuel. Maintenance of constant pressure at the moment of injection is provided with a regulator of pressure and a suppressor of pulsations of pressure (the last is mounted about the fuel filter).

The system of injection of fuel of considered cars consists of 3 subsystems – fuel, a fence of air and the processor control unit.

Fuel system

The fuel pump provides supply of fuel via the filter in the distributor under constant pressure. Stabilization of pressure of fuel on an exit of the distributor is provided with a pressure regulator.

System of a fence of air

Consists of an air purifier, a measuring instrument of a stream of air, the throttle branch pipe, a soaking-up collector and connecting hoses and branch pipes. The measuring instrument of a stream of air of lopastny type, a consumption of air is proportional to an angle of rotation of a zaslonka and resistance of the potentiometer, rigidly connected with a zaslonka axis.

Electronic control unit

On the car the electronic control unit (ECU) which provides automatic adjustment of the moment of ignition and also quantity and structure fuel - an air mix according to information from the various sensors tracing power setting is established. The structure of auxiliary elements of system (sensors, switches, etc.) is defined by a concrete type of applied system of injection.

Applied systems of injection

System of injection of the L-Jetronic type of Bosch firm (till 1987)

System of injection of L-Jetronic
1. Fuel tank
2. Rapredelitel of fuel
3. Pressure regulator
4. Processor block
5. Relay
6. Measuring instrument of speed of a stream
7. Ignition switch
8. Battery
9. Butterfly valve
10. Butterfly valve switch
11. Valve of start of the cold engine
12. Proof-reader of idling
13. Ignition distributor
14. Thermotimer
15. Sensor of temperature of the engine
16. Oxygen sensor
17. Nozzle
18. Fuel фильт
19. Fuel pump

System odnoforsunochny with an electromagnetic nozzle. The basic in adjustable parameters are duration of an open condition of nozzles (amount of injected fuel) and idling turns. Auxiliary elements of system are the sensor of temperature of cooling liquid, the butterfly valve switch, the idling stabilizer (Perepuskny the air valve), the relay and safety locks.

System of injection of the Motronic type

System of injection of Motronic
1. Fuel tank
2. Processor block
3. Quencher of pulsations
4. Regulator of pressure of fuel
5. Valve of start of the cold engine
6. Butterfly valve switch
7. Measuring instrument of speed of a stream
8. Proof-reader of idling
9. Relay of the fuel pump
10. Main relay
11. Ignition switch
12. Battery
13. Sensor of an angle of rotation of the crankshaft
14. Butterfly valve
15. Sensor of speed of rotation of the crankshaft
16. Sensor of temperature of the engine
17. Thermotimer
18. Oxygen sensor
19. Ignition coil
20. Candle
21. Nozzle
22. Ignition distributor
23. Fuel pump
24. Fuel filter
25. Fuel distributor

System mnogoforsunochny with electromagnetic nozzles. Adjustable parameters are the amount of injected fuel, the ignition moment, turns of idling and composition of exhaust gases.