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N55 Engine
Fuel Injectors
The high pressure fuel injection valve Bosch HDEV5.2 is a solenoid type injector. In con-
trast to the piezo-electric injectors used on the current BMW engines, the solenoid valve
fuel injectors are designed as inward-opening multi-hole valves with highly variable jet
angle and form. They operate at a system pressure of up to 200 bar.
Do not open the fuel system if the coolant temperature is
above 40°C/104°F. The residual pressure in the high pres-
sure fuel system could cause bodily injury.
It is essential to observe the utmost cleanliness when working on the high pressure fuel
system and to follow the proper working procedures described in the repair instructions.
Even minute soiling or damage at the thread connections of the high pressure lines could
cause leaks.
Note: Special tool # 13 0 270 must be used to remove the HDEV5.2 high pres-
sure injector valves from the engine. Damage to the injector or the relat-
ed components may occur otherwise. See the Service Information sec-
tion in this training material for more information.
Particular care must be taken when working on the fuel system of the N55 engine to
ensure that the ignition coils are not wet with fuel. The resistance of the silicone insulating
material of the coils is greatly reduced by the contact with fuel. This could result in arcking
at the top of the spark plug and misfiring. See the Service Information section and repair
instructions for more information.
CAUTION!!!
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