Fuel Pressure Test

NOTE: The following test procedures assume that the ignition system is functioning, and that a good spark is evident at the plugs. Ensure that this is the case prior to proceeding with fuel system diagnosis.

Fuel Injector Connector:

1. Relieve fuel system pressure. Service and Repair
2. Disconnect the fuel supply hose from the fuel rail, and install fuel line adaptor, tool number C-4799 or equivalent.

Fuel Line Disconnect Tool 6182:

Using Fuel Tube Disconnect Tool No. 6182:

3. Connect fuel system pressure gauge, tool number C-3292, or suitable substitute, with a range of 0-60 psi to the adaptor.
4. Place ignition switch in RUN position to activate fuel pump and pressurize system. If fuel pump fails to actuate, check Auto Shut Down (ASD) relay operation.
5. After actuating fuel pump the gauge should read 48 psi (330 kPa).
- If fuel pressure is below specification proceed to step 6.
- If fuel pressure is above specification proceed to step 7.
- If pressure is within specified limits problem is injector related.
Testing and Inspection

6. If fuel pressure is below specification, move pressure gauge to fuel supply line and install between fuel tank and fuel filter. Repeat test procedure, and check fuel system pressure. If pressure is 5 psi higher than previous reading and within specification, replace fuel filter. If no change occurs in pressure, gently squeeze fuel return hose. If pressure increases to specification, replace fuel pressure regulator. If no change in pressure occurs, the fuel pump is defective and must be replaced.
7. If fuel pressure is above 48 psi (330 kPa) remove fuel return hose from fuel pressure regulator end, and install a suitable hose from fuel pressure regulator output. Place the other end of the hose in a clean and approved container. Start engine and observe fuel pressure. If pressure is now within specification, problem is a restriction in fuel return line, or an obstructed fuel return check valve in tank. Clear return line obstruction if necessary, and or replace fuel tank assembly if in-tank check valve is obstructed. If pressure is still above specification replace fuel pressure regulator.