Warning! Gasoline is extremely flammable and explosive, so care must be taken when working on any part of the fuel system.
Warning: The container that held the fuel contains fuel vapor and is potentially explosive.
Attention! Work on the fuel system must be carried out in a well-ventilated area, for which you can open all the windows and doors to create a draft.
Warning! When working on the fuel system, do not use open flames, electric welding or tools that may generate sparks. Make sure that a charged fire extinguisher is in the immediate vicinity of the work area.
Warning! Use goggles to protect your eyes from fuel getting into them. If fuel gets on your skin, rinse the area with plenty of water.
Caution! When working with the fuel system, keep it clean, as dirt that gets into the fuel system channels can block them, which will disrupt the normal operation of the engine.
The fuel system consists of a fuel pump, pressure accumulator, fuel filter, fuel injectors, pressure regulator, fuel distributor and fuel lines.
When the engine is running or after the ignition is turned on, the fuel in the fuel system is under constant pressure. When working on the fuel system, it is necessary to first relieve the pressure in the system. It is advisable to perform work to relieve the pressure in the fuel system on a cold engine.
Original article is on the portal (MERCEDESMAN)
The pressure in the fuel system can be relieved using an additional valve located at the end of the fuel line. To perform this operation, it is necessary to use special equipment with a fuel supply hose under pressure with adapters. If there is no special equipment for relieving pressure in the fuel system, you can use the alternative method described below.
Remove the fuel pump relay, then run the engine in idle mode until it stops. Due to the fact that the engine consumes fuel, and the fuel pump does not pump fuel into the fuel system, the pressure in the fuel system decreases significantly.
Remove the ground wire from the battery. Remove the fuel filler cap to equalize the pressure in the fuel tank with the atmospheric pressure. Replace the fuel filler cap.
Place a container under any fuel line connection and have a rag handy to absorb any spilled fuel.
Carefully loosen the fuel line connection slowly. Cover the fuel line connection with a clean rag to prevent fuel from splashing out. After relieving the pressure in the fuel system, completely unscrew the fuel line and plug its ends with plugs.