Removal and installation injector nozzles (BMW 3 Series E36)

Defective injectors can cause strong knocking in the engine, the cause of which can be mistakenly attributed to the destruction of bearings. In such cases, let the engine run at idle speed and sequentially unscrew the union nuts of the distribution pipe. If the knocking disappears when unscrewing one of the union nuts, the corresponding injector is defective.

The injectors are tested using special equipment (work at a service station).

The first signs of problems with the injectors are as follows:

• misfires
• knocking in one or more cylinders
• engine overheating
• engine power reduction
• excessively strong black exhaust
• increased fuel consumption

Removal

Disconnect the ground wire from the battery.

Caution: When the battery is disconnected, the information in the electronic memory devices, such as the engine fault memory or the radio security code memory, is erased. Disconnect the battery only when the ignition is off, so as not to damage the fuel injection system control unit. When disconnecting the battery, follow the instructions in the sections "Radio" and "Removing and installing the battery".

Remove the cover over the injectors by unscrewing the mounting bolts.

Clean the injection tubes thoroughly.

Disconnect the injection tubes as a set, for which unscrew the union nuts with a wrench, for example HAZET 4550.

Caution: Do not change the bend of the tubes. Put the appropriate protective caps on the injectors and on the high-pressure fuel pump to prevent dirt from getting in.

If the injection tube mounting brackets are removed, first mark their installation position with a felt-tip pen.



Carefully remove the fuel drain hoses from the injectors.

Remove the injector nozzles using a 27 mm wrench, such as HAZET 4555. To prevent dirt from getting in, place protective caps on the lower parts of the injectors.

Caution: Do not allow the injectors to fall.

Remove the heat-insulating washer.

Installation

It is essential to install new heat-shielding washers between the cylinder head and the injectors. The washer is installed with the recess facing upwards, the arrow points to the cylinder head.



Screw in the nozzle and tighten to a torque of 40 Nm.

Install the injection pipes. Tighten the union nuts to a torque of 20 Nm.

If removed, insert the mounting brackets in accordance with the markings made.

Connect the fuel drain hoses.

Connect the ground wire to the battery.

Start the engine and check the fuel system for leaks.