Fuel Pressure
WARNING:
ALWAYS relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components. See FUEL PRESSURE RELEASE .
- Visually inspect fuel system, including fuel lines, connections, injectors and electrical connections. Ensure Inertia Fuel Shutoff (IFS) switch is not tripped. Check condition of battery and fuses. Ensure fuel level in tank is sufficient.
- Turn ignition switch to OFF position. Release fuel pressure. Install fuel pressure gauge. Start engine and increase engine speed to 2500 RPM. If engine will not start, cycle ignition switch several times. Measure and record fuel pressure. See FUEL PRESSURE SPECIFICATIONS table. If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, see TEST HB: NATURAL GAS FUEL DELIVERY SYSTEM for 4.6L Natural Gas or TEST HC: GASOLINE FUEL DELIVERY SYSTEM for all others in SELF-DIAGNOSTICS - EEC-V (GASOLINE) article for fuel delivery system diagnosis.
- With fuel pressure gauge still installed, cycle ignition switch on and off several times. Record fuel pressure. After one minute with ignition off, fuel pressure should remain within 5 psi (34 kPa) of maximum fuel pressure on gasoline engines and within 10 psi (69 kPa) of maximum fuel pressure on Crown Victoria (NGV). If fuel pressure remains within specification, system is capable of maintaining fuel pressure. If fuel pressure does not remain within specification, check for leaking fuel injectors or fuel pressure regulator.
NOTE:
When ignition switch is turned to ON position, fuel pump will only run for approximately 8 seconds before shutting off. Cycling ignition switch may be necessary to achieve maximum fuel pressure. DO NOT crank engine.