Note. Before starting work, read the precautions in Section Safety precautions and cleanliness when working with the fuel system
Attention! After performing the procedure described below, you will only remove excess pressure from the fuel system. Gasoline will remain in the pipelines. Take all necessary precautions before disconnecting any fuel hose.
The fuel system considered in this Chapter consists of a fuel tank, a fuel pump located inside it with a fuel reserve sensor, a fuel filter, injectors, a pressure regulator and various hoses and tubes. Inside all these nodes during engine operation (as well as with the ignition on) fuel is under pressure.
After turning off the ignition, the pressure in the system remains for quite a long time. Before disconnecting any of the components mentioned above, the pressure must be relieved.
The simplest way to relieve pressure is as follows. Remove the fuel pump fuse and start the engine. If the engine does not start, crank it with the starter for a few seconds, and if it starts, wait for it to stop spontaneously. In order to completely relieve pressure, turn the crankshaft of the engine with a starter a couple of turns. Turn off the ignition and replace the pump fuse.
The pressure relief valve located on the fuel rail works on the principle of a simple nipple. Place a rag around the valve, remove the cap and push on the nipple. Don't forget to put the cap back on when you're done.
Be aware that if the pressure is released (or fuel has been removed from the system), the engine will take longer than usual to start. You will have to crank the engine with the starter for at least a few seconds, during which time the pressure in the system will be restored and the fuel will fill all the pipelines.