BMW 3 Series E30

since 1983-1994 release

Repair and operation of the car



BMW E30
+ 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. Air stream measuring instrument
   6.5. Throttle branch pipe
   6.6. Fuel pressure regulator
   6.7. Nozzle of launch of the cold engine and thermotimer
   6.8. Check and replacement of nozzles
   6.9. Air proofreader 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. Fuel pipes and union
   6.14. Fuel tank
   6.15. Air filter
   6.16. Cable of the 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. Useful tips



6.11. Check of pressure of fuel

GENERAL INFORMATION

CARBURETTOR ENGINES

For check of pressure of fuel it is necessary to turn on the manometer between the fuel pump and a tube of supply of fuel in the carburetor. It is also necessary to zashuntirovat the backpressure fuel valve which is switched on in the highway after the fuel pump.

PERFORMANCE ORDER
In the absence of the manometer pressure can be checked on a stream from the hose disconnected from the pump, turning the engine a starter (disconnect also high-voltage wire from the ignition coil).

INJECTOR ENGINES


Prevention

The fuel filter has to be in satisfactory condition. If the filter is littered, then it should be replaced.


On cars with the pumping pump pressure is measured during the operation of the main pump and pump of pumping.

Check of operation of the main fuel pump and pump of pumping

PERFORMANCE ORDER
1. In system of injection L-Jetronic you peremknit conclusions 30 and 87b on the socket of the relay of the fuel pump.
2. In the Motronic system you peremknit conclusions 30 and 87.
3. On models after 1987 for access to the relay and the control unit turn off 4 bolts and uncover.
4. Then you peremknit conclusions 30 and 87 on the relay socket.

At inclusion of ignition from a tank the sound of the working pump has to be listened. This procedure belongs also to the pumping pump.

Check of pressure of fuel

PERFORMANCE ORDER
1. Execute a decompression and disconnect the battery from weight.
2. In system of injection L-Jetronic and the early Motronic systems disconnect the highway of supply of fuel on the fuel distributor. On the late Motronic systems disconnect the highway on the fuel filter.
3. Turn on the manometer in a rupture of the highway.
4. Connect the battery to weight, you peremknit conclusions to the pump relay, include ignition and consider pressure.
5. If pressure is lower than norm, then check existence of leaks in system, replace the filter and repeat measurements, check pressure developed by the pump and a condition of the regulator of pressure.
6. If pressure is higher than norm, then check a condition of the return fuel pipe. If the fuel pipe is not littered, then replace pressure regulator.
7. Check pressure 5 minutes later after switching off of ignition. If pressure is lower than norm, then check existence of leaks in system, check pressure developed by the pump, a condition of the regulator of pressure and nozzles.

Check of pressure of the fuel developed by the pump


Prevention

For measurements the manometer joins directly the pump and the standard procedure of a decompression after tests is inapplicable. Therefore, the manometer with the pitting valve is required.


PERFORMANCE ORDER
1. Execute a decompression and disconnect the battery from weight.
2. Disconnect the highway of supply of fuel on the distributor of fuel and attach the manometer to the highway.
3. Connect the battery to weight, you peremknit conclusions to the pump relay, include ignition and consider pressure.
4. If pressure is lower than norm, then check existence of leaks in system. If the system is tight, then replace the pump.
5. Check pressure 5 minutes later after switching off of ignition. If pressure is lower than norm, then check existence of leaks in system. If the system is tight, then replace the pump.
6. Remove a crossing point and dump pressure, having sent a fuel stream to a vessel.

Check of the pump of pumping of fuel

PERFORMANCE ORDER
1. Execute a decompression and disconnect the battery from weight.
2. Remove the pumping pump hatch (is under a back seat or under a rug in a luggage carrier, depending on model). Attach the manometer to the final union of the pump.
3. Connect the battery to weight, you peremknit conclusions to the pump relay, include ignition and consider pressure. If pressure is lower than norm, then replace the pumping pump.

Check of the relay of the fuel pump

Scheme of the device of the relay of the fuel pump and designation of conclusions (4-cylinder engine)

1. Signal from a starter
2. Signal of rotation of the crankshaft
3. Battery tension
4. To the fuel pump (+)
5. Control of level of fuel
6. Weight
7. Battery tension at inclusion of ignition

Scheme of the device of the relay of the fuel pump and designation of conclusions (6-cylinder engine)

1. Battery tension
2. Tension (+) from the main relay
3. Weight from the Motronic control unit
4. To the fuel pump (+)

The relay of the fuel pump on the 4-cylinder engine (A) and on the 6-cylinder engine (B)


PERFORMANCE ORDER
1. Include ignition and check presence of tension of the battery on conclusions 30 (M10 engine) or 15 (M20 and M40) from a reverse side of the socket of the relay.
Prevention

If in cars with the battery in which it is mounted in tension luggage carrier on these conclusions is not present, then check a condition of a fusible crossing point (for current 50 A, located in 15 cm from the battery).


2. Switch off ignition, disconnect the relay from the socket, connect the voltmeter between conclusions 85 (-) and 86 (+) (M20 engine) or between a conclusion 50 and the weight (M10 and M40) and check presence of tension of the battery between these conclusions at inclusion of a starter.
3. In the absence of tension check safety locks and a chain. If tension is, but the pump works only with a crossing point, then replace the relay.
4. If the pump does not work also after replacement of the relay, then check tension on pump conclusions (see subsection 6.12). If necessary replace the pump.