Caution: Following the procedure below will only relieve excess pressure in 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 or nozzles, 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.
To do this, briefly open the fuel tank cap and close it again. Lay a thick rag over the joint. Wear protective goggles. In direct injection system AWA engine only the low-pressure part of the system can be depressurized in the manner described (up to 6 atm.). To relieve high pressure (up to 110 atm.) special devices are required. High pressure in the system is present in the area from the injection pump to the injectors. At diesel engine 1.9 l the temperature of the fuel lines and fuel in an engine with unit injectors can be up to 100°C in extreme cases. Allow the fuel to cool before opening the connections, as otherwise it may burn.
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, let the engine idle until it stalls on its own. In order to completely relieve pressure, turn the crankshaft of the engine with a starter for a couple of turns. Turn off the ignition and replace the pump fuse.
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.
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