Fuel Pressure: Testing and Inspection

Fuel Pump Connector And Relay Location:

Note:
a. When reconnecting fuel line, always use new clamps.

b. Make sure that clamp screw does not contact adjacent parts.

c. Use a torque driver to tighten clamps.

d. Use Pressure Gauge to check fuel pressure.

e. Do not perform fuel pressure check while fuel pressure regulator control system is operating; otherwise, fuel pressure gauge might indicate incorrect readings.

Fuel Pressure Check

1. Release fuel pressure to zero.

2. Disconnect fuel hose between fuel filter and fuel tube (engine side).

3. Install pressure gauge between fuel filter and fuel tube.

4. Start engine and check for fuel leakage.

5. Read the indication of fuel pressure gauge.

At idling:

When fuel pressure regulator valve vacuum hose is connected.

Approximately 250.1 kPa
(36.3 psi)

When fuel pressure regulator valve vacuum hose is disconnected.

Approximately 299.1 kPa
(43.4 psi)

6. Stop engine and disconnect fuel pressure regulator vacuum hose from intake manifold.

7. Plug intake manifold with a rubber cap.

8. Connect variable vacuum source to fuel pressure regulator.

Vacuum/fuel Pressure Test:

9. Start engine and read indication of fuel pressure gauge as vacuum is changed.

Fuel pressure should decrease as vacuum increases. If desired results were achieved, test is complete. If results were unsatisfactory continue.

10. If pressure readings were consistently high, check fuel return lines for restriction and replace pressure regulator if lines OK. If pressure readings were consistently low, continue.

11. With engine idling, use a smooth jawed pair of pliers and gently pinch fuel return line.

10. If pressure rises to normal or above replace pressure regulator. If pressure does not increase, replace fuel pump.