Removal and installation injector nozzles (BMW 5 Series E34)

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.

A defective injector can also be identified by successively unscrewing the union nuts of the distribution pipe at accelerated idle speed. If the engine speed does not change after unscrewing one of the union nuts, the corresponding injector is defective. Injectors are checked using a pressure gauge (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

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.

Remove the injector nozzles using a 27 mm wrench, for example HAZET 4555.

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±5 Nm.

Install the injection tubes. Tighten the union nuts to a torque of 20±5 Nm.