Pressue Tests

Pressure Test

1. Relieve fuel system pressure by starting engine with fuel pump relay (circuit open relay) disconnected and let run until engine dies. Then slowly and carefully remove hose on outlet side of fuel filter. Cover with a clean rag while removing hose, to avoid spraying fuel in your face.

Checking Fuel System Pressure:

2. Using an extra piece of fuel injection hose and a fuel "tee" fitting, connect fuel pressure gauge between fuel filter and primary fuel rail (see illustration).

Jumping Fuel Pump Test Connector:

3. Energize fuel pump by bridging the terminals of the yellow fuel pump test connector (located on the right side of the engine compartment, near the McPherson strut tower) and turn the ignition "ON" .

4. Pinch the fuel hose closed, between where the gauge is tee'd into the fuel line and the primary fuel rail, using a pinch clamp.

5. Observe fuel pressure on gauge (this will be the maximum fuel pressure available from the fuel pump).

71 - 92 psi (490 - 637 kPa)

If pressure is higher than the maximum specified, replace fuel pump. If pressure is lower than the minimum specified, check fuel filter. If filter is OK, replace pump.

6. Turn ignition "OFF", wait 5 minutes, and observe fuel pump residual pressure. After the specified off time, the fuel pump pressure relief valve should retain a minimum fuel pressure as listed below.

57 psi (392 kPa)

If not, replace pump.

7. Remove pinch clamp from hose between gauge and pulsation damper.

8. Start engine and let idle.

9. Observe fuel pressure on gauge (this is the system operating pressure).

27 - 33 psi (186 - 226 kPa)

If pressure is higher than the maximum specified, check fuel return line for kinks or restriction. If pressure is lower than the minimum specified, check fuel filter. If filter and return line are OK and pressure is still not within the specified range, replace pressure regulator.

10. Disconnect vacuum hose from fuel pressure regulator with engine idling.

^ Fuel pressure should increase when vacuum hose is removed.

34 - 40 psi (235 - 275 kPa)

If not, replace pressure regulator.

11. Shut engine "OFF" and wait 5 minutes, then observe residual system pressure on gauge. After the specified off time, the pressure regulator should retain a minimum fuel system pressure as listed below.

Minimum 18 psi (128 kPa)

If not, check for leaking fuel injector(s). If injectors are not leaking, replace pressure regulator.

If all test results are OK, fuel pump and pressure regulator are OK.