Fuel Pressure: Testing and Inspection
FUEL PRESSURE TEST1. Release residual pressure from the fuel line to prevent fuel spray.
2. Disconnect the high pressure fuel hose at the fuel rail side.
CAUTION: Cover the hose connection with rags to prevent splash of fuel that could be caused by some residual pressure in the fuel pipe line.
3. Remove the union joint and bolt from the special tool (adapter hose MD998709) and instead attach the special tool (hose adapter MD998742) to the adapter hose.
4. Install the special tool (for measuring the fuel pressure) that was set up in step 3.
1. Install the special tool (for measuring the fuel pressure) between the high-pressure fuel hose and the fuel rail.
2. Install the fuel pressure gauge set (special tool) on the special tool (for measuring the fuel pressure) putting the gasket between them.
3. Connect the lead wire of the fuel pressure gauge set (special tool) to the power supply (cigarette lighter socket) and to the scan tool.
1. Install the fuel pressure gauge on the special tool (for measuring the fuel pressure) putting a suitable O-ring or gasket between them.
2. Install the special tool which was set up in step (1) between the high-pressure fuel hose and the fuel rail.
5. Connect the scan tool to the data link connector.
6. Turn the ignition switch to ON. (But do not start the engine.)
7. Use the scan tool to operate the fuel pump. Check that there are no fuel leaks from any parts.
8. Finish the actuator test or turn the ignition switch to OFF.
9. Start the engine and run at idle.
10. Measure fuel pressure while the engine is running at idle.
Standard value: Approx. 270 kPa (38 psi) at curb idle
11. 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
12. Check to see that fuel pressure at idle does not drop even after the engine has been raced several times.
13. 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.
14. If any of fuel pressure measured in steps 10 to 13 is out of specification, troubleshoot and repair according to the table.
15. Stop the engine and observe fuel pressure gauge reading. Normal if the reading does not drop within 2 minutes.
If it does, observe the rate of drop and troubleshoot and repair according to the table.
1. Squeeze closed the fuel return line to confirm leak-down occurs from defective fuel pressure regulator.
2. Squeeze closed the fuel supply line to confirm leak-down occurs from defective fuel pump check valve.
3. If pressure continues to drop with both fuel lines squeezed closed, injector(s) are leaking.
16. Release residual pressure from the fuel pipe line.
17. Remove the fuel pressure gauge and special tool from the fuel rail.
CAUTION: Cover the hose connection with rags to prevent splash of fuel that could be caused by some residual pressure in the fuel pipe line.
18. Replace the O-ring at the end of the high pressure fuel hose with a new one.
19. Fit the high pressure fuel hose into the fuel rail and tighten the bolts to specified torque.
Tightening torque: 5 Nm (3.6 ft.lbs.)
20. Check for fuel leaks.
1. Use the scan tool to operate the fuel pump.
2. Check the fuel line for leaks, repair as needed.
21. Disconnect the scan tool.