Mercedes S-Class W-220

since 1998 release

Repair and operation of the car

Mercedes W220
+ Mercedes-Benz cars of the class S (W220)
+ Operation manual
+ Routine maintenance
+ Engine
+ Cooling system and heating
- Power supply system and release
   - Power supply system and fuel injection
      Dropping pressure in fuel system of the petrol engine
      Management of distribution of power - the description and the principle of the organization of function of shutdown of cylinders
      Supercharger of air
      Check and adjustment of speed of the single course / moment of ignition/concentration WITH
   + System of injection of fuel of the diesel engine. Turbocompressor
   + Systems of release and decrease in toxicity of the fulfilled gases
+ Engine electric equipment
+ Automatic transmission
+ Power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Schemes of electric equipment

Dropping pressure in fuel system of the petrol engine

Before getting to work, get acquainted with the precautionary measures given in the previous Section.

 Attention! After implementation of the procedure described below you only remove excessive pressure from fuel system. In pipelines there will be a gasoline. Before disconnecting any fuel hose, take all necessary precautionary measures.


1. The fuel system considered in this Chapter consists of the fuel tank located in it the fuel pump with the sensor of a reserve of fuel, the fuel filter, injectors, the regulator of pressure and various hoses and tubes. In all these knots in operating time of the engine (and also at the included ignition) fuel is under pressure.
2. After switching off of ignition pressure in system remains still quite long time. Before a detachment of any of mentioned above a component pressure it is necessary to lower.
3. The simplest way of dumping of pressure is following. Take a safety lock of the fuel pump and start the engine. If the engine is not started, turn it a starter within several seconds and if it is started, allow the engine to work at single turns until he does not decay. Completely to dump pressure, turn the engine crankshaft a starter on couple of turns. Switch off ignition and return into place a pump safety lock.
4. The valve of dumping of pressure located works at the fuel distributive highway by the principle of the simple nipple. Place rags around the valve, remove a cap and press on the nipple. After completion of work do not forget to return a cap into place.
5. Keep in mind that if pressure is dumped (or fuel is removed from system), start of the engine will take bigger, than usually, time. You should turn the engine crankshaft a starter at least several seconds during which pressure in system will be restored, and fuel will fill all pipelines.