Fuel Pressure: Testing and Inspection

1. Release residual pressure from the fuel pipe line to prevent fuel gush out.

Fuel Pressure Test:

2. Disconnect the fuel high pressure hose at the fuel rail side.

CAUTION: Cover the hose connection with rags to prevent splash of fuel caused by some residual pressure in the fuel pipe line.

3. Remove the union joint and bolt from the special tool (adapter hose MD9987O9 or equivalent) and instead attach the special tool (hose adapter MD998742 or equivalent) to the adapter hose.
4. Install a fuel pressure gauge on the adapter hose that was set up in step (3).

NOTE: Use a suitable 0-ring or gasket between the fuel pressure gauge and the special tool to prevent fuel leaks.

5. Install the special tool, which was set in place in steps (3) and (4) between the fuel rail and the high pressure hose.

Fuel Pressure Test:

6. Drive the fuel pump by connecting the fuel pump drive terminal to the battery (+) terminal using a jumper wire. Check for leaks.
7. Disconnect the jumper wire from the fuel pump drive terminal to stop the fuel pump.
8. Start the engine and run at idle.
9. Measure fuel pressure while the engine is running at idle.

Standard value: Approximately 270 kPa (38 PSI) at curb idle

Fuel Pressure Test:

10. Disconnect the vacuum hose from the fuel pressure regulator and measure fuel pressure with the hose end closed by a finger.

Standard value: 330-350 kPa (47-50 PSI) at curb idle

11. Check to see that fuel pressure at idle does not drop even after the engine has been raced several times.
12. Racing the engine repeatedly, hold the fuel return hose lightly with fingers to feel that fuel pressure is present in the return hose.

NOTE: If the fuel flow rate is low, there will be no fuel pressure in the return hose.

13. If any of fuel pressure measured in steps (8) to (11) is out of specification, troubleshoot and repair according to the table below.

Fuel Pressure Test:

14. Reduce the internal pressure of the fuel pipes and hoses.
15. Remove the fuel pressure gauge and special tools from the fuel rail.

CAUTION: Cover the hose connection with a shop towel to prevent splash of fuel that could be caused by some residual pressure in the fuel pipe line.

16. Replace the 0-ring at the end of the fuel high pressure hose with a new one.
17. Fit the fuel high pressure hose over the fuel rail and tighten the bolt to specified torque.

- Tightening torque: 5 Nm (3.6 ft.lbs.)

18. Check for fuel leaks.
- Apply the battery voltage to the fuel pump drive terminal to drive the fuel pump.
- Under fuel pressure, check the fuel line for leaks.