Relieving pressure in the fuel system of a gasoline engine (Mercedes-Benz G-Class W463)

Note: Before you begin, read the safety precautions in Section General information and safety precautions.

Caution! After performing the procedure described below, you will only remove excess pressure from the fuel system. Gasoline will remain in the lines. Before disconnecting any fuel hose, take all necessary precautions!

The main components of fuel systems of gasoline engines are the fuel tank, the fuel pump located inside it with a fuel level sensor, a fuel filter, injectors, a pressure regulator and a set of connecting lines.

When the engine is running, the fuel inside the fuel system path is under pressure, which continues to be maintained for a fairly long time after the ignition is turned off. Before disconnecting any of the system components, the pressure in the stroke must be released.

The simplest way to relieve pressure in the fuel system is to start the engine with the fuel pump fuse removed - wait until the engine stops on its own, then, to ensure complete pressure relief, turn it over several more times with the starter. If the engine fails to start, turn it over with the starter for several seconds. After completing the procedure, turn off the ignition and put the removed fuse back in place.



At service stations, the pressure in the fuel system is released through a service valve located on the fuel distribution line and operating on the principle of a simple nipple. Wrap the valve in a rag, remove the cap and press on the nipple - do not forget to return the cap to its place after completing the procedure.

Remember that after releasing the pressure/removing fuel from the fuel system, it takes a little longer than usual to start the engine - you will have to turn the crankshaft with the starter for several seconds until the pressure in the system is restored and the fuel fills all the fuel lines.