Mercedes S-Class W-140

1991-1999 of release

Repair and operation of the car


Mercedes S-Class
+ Mercedes-Benz cars of the class S (W-140)
+ Operation manual
+ Routine maintenance
+ Engine
+ Cooling systems, heating
- Power supply system and release
   - A power supply system and injection of fuel of the petrol engine - the general information
      Security measures and rules of respect for purity during the work with fuel system
      Dropping pressure in fuel system of the petrol engine
      Check and adjustment of speed of the single course / moment of ignition/concentration WITH
   + System of injection of fuel of the diesel engine - the general information
   + Control system of injection of fuel and HFM-SFI ignition (6-cylinder petrol engines)
   + Control systems of the LH-SFI and ME-SFI engine (8-cylinder petrol engines)
   + Control systems of injection of fuel and ignition of ME-SFI and LH-SFI (12-cylinder petrol engines)
   + Control system of fuel injection (diesel engines of the OM603.971 series)
   + Control system of fuel injection (diesel engines of the OM606.961 series)
   + System of a turbo-supercharging - the general information
   Systems of decrease in toxicity of release - the general information
   System of production of the fulfilled gases - the general information
   Catalytic converter (petrol models)
+ Engine electric equipment
+ Gear shifting box
+ Automatic transmission
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment






Dropping pressure in fuel system of the petrol engine

Before getting to work, get acquainted with the precautionary measures given in the Section of the Security measure and the rule of respect for purity during the work with fuel system

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.

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, nozzles, 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.

After switching off of ignition pressure in system remains still quite long time. Before a detachment of any of the components mentioned above pressure needs to be dumped.

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, wait for its spontaneous stop. 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.

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.

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.