Note: Before working on the power supply system, please read the safety precautions in paragraph 1.
Warning: This procedure only relieves the pressure in the fuel system. Remember, however, that fuel will still be contained in the system components, so take appropriate precautions before disconnecting the components.
1. The fuel system considered in this paragraph consists of a fuel pump located in the fuel tank, a fuel accumulator, a fuel filter, fuel injectors, a fuel pressure regulator, a fuel distributor, and metal tubes and flexible hoses connecting these elements.
2. All the above mentioned parts contain gasoline, which is under pressure when the engine is running or when the ignition is turned on. The system remains under pressure for some time after the ignition is turned off, and before working on any element of the system, it is necessary to reduce the pressure in the system in a controlled manner. It is best to allow the engine to cool completely before carrying out repair work.
3. Refer to Chapter 12 and locate the fuel pump relay. Remove the relay from the housing, then crank the engine with the starter for a few seconds. The engine may start and run for a while. However, continue to crank the engine until it stops. The injectors must be open long enough to relieve the pressure in the fuel line.
4. Disconnect the negative battery cable. Open the gas cap briefly to relieve pressure in the gas tank. Then close the cap.
5. Place a suitable container under the appropriate connection or fitting to be disconnected and have a large rag ready to catch any gasoline that spills past the container.
6. Slowly loosen the union or nipple nut (depending on what is required) to avoid a sudden release of pressure and cover the connection with a rag to stop the stream of gasoline that may flow out from under the loose connection. Once the system is depressurized, disconnect the fuel line and insert plugs to minimize fuel loss and prevent dirt from getting into the fuel system.