Gasoline Engines

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.

NOTE: When ignition switch is turned to ON position or scan tool activates fuel pump, fuel pump will only run for approximately 8 seconds before shutting off. Cycling ignition switch or scan tool may be necessary to achieve maximum fuel pressure. DO NOT crank engine.

Turn ignition switch to OFF position. Release fuel pressure. Install fuel pressure gauge. Install scan tool. Turn ignition switch to ON position, with engine off. Using scan tool, run fuel pump to obtain maximum fuel pressure. Measure and record fuel pressure. See FUEL PRESSURE SPECIFICATIONS . If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, see TEST HB for 4.6L (CNG), or TEST HC for all others in SELF-DIAGNOSTICS - EEC-V - CNG & 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. 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.