Fuel is extremely flammable, so take extra precautions when working on any part of the fuel system. Do not smoke or allow open flames or lamps without shades near the work area. Do not work in a garage with natural gas equipment (such as water heaters or clothes dryers) with wick. If fuel comes into contact with skin, wash immediately with soap and water. Always wear safety goggles and have a fire extinguisher ready for any work on the fuel system.
If your vehicle's radio is equipped with an anti-theft system, make sure you know the correct activation code before disconnecting the battery. Before disconnecting the wire, refer to Section Anti-theft audio system and instrument panel language.
If, after connecting the battery, a message in a different language appears on the instrument panel display, refer to Section Anti-theft audio system and instrument panel language.
Examination
1. Depressurize the fuel system (see Section Relieving pressure in the fuel injection system).
2. Disconnect the negative battery cable.
3. Disconnect the fuel line and connect a fuel pressure gauge (see Section Fuel/Fuel Pump Pressure Check). Connect the battery.
4. Pressurize the fuel system (install the fuel pump fuse and turn on the ignition) and check the meter connections for leaks.
5. Connect a vacuum pump to the fuel pressure regulator.
6. Turn on the fuel pump (see Section Fuel/Fuel Pump Pressure Check). Take readings of the fuel pressure gauge when vacuum is applied to the pressure regulator and when it is not. The fuel pressure should decrease as the vacuum increases.
7. Turn off the fuel pump and attach a vacuum hose to the regulator. Start the engine and check the fuel pressure at idle by comparing it with that given in Table of sizes and adjustment data at the end of the Guide. Disconnect the vacuum hose and observe the meter - when the hose is disconnected, the pressure should increase abruptly to the maximum.
8. If the fuel pressure is low, shut off the fuel return line and observe the pressure. If the pressure does not increase, then the fuel pump is faulty or the fuel line is clogged. If the pressure does not rise abruptly, replace the pressure regulator.
9. If the measured fuel pressure is very high, stop the engine, disconnect the fuel return line and purge it to check for blockage. If the line is not clogged, replace the fuel pressure regulator.
10. If the pressure value does not change, as described in paragraph 7, attach a vacuum gauge to the vacuum hose of the pressure regulator and measure the vacuum (the engine is idling).
11. If vacuum is present, replace the fuel pressure regulator.
12. If the meter does not register vacuum, check for leaks or blockages in the hose and inlet.
Replacement
1. Depressurize the fuel system (see Section Relieving pressure in the fuel injection system).
2. Disconnect the negative battery cable.
If your vehicle's radio is equipped with an anti-theft system, make sure you know the correct activation code before disconnecting the battery. Before disconnecting the wire, refer to Section Anti-theft audio system and instrument panel language.
If a message in a different language appears on the instrument panel display after connecting the battery, refer to Section Anti-theft audio system and instrument panel language.
3. Disconnect the vacuum hose and the fuel return hose from the pressure regulator, then unscrew the mounting bolts (shown by arrows).
4. Remove the pressure regulator.
5. Installation is reverse to removal. Make sure a new O-ring is installed. Before installing, apply a thin layer of impellent oil to the ring.
6. After installing the pressure regulator, check for fuel leaks.