Fuel Pressure: Testing and Inspection

FUEL PUMP OPERATION CHECK
1. Set the ignition switch at OFF.





2. Check that when the baftery Voltage is directly applied to the fuel pump check terminal, the operating sound of the pump can be heard.

NOTE:Since the fuel pump is installed in the fuel tank, its operating sound cannot be readily heard. Remove the fuel tank cap and listen to the operating sound through the filler port.





3. Hold the high pressure fuel hose between your fingers and check that the fuel pressure can be felt.

FUEL PRESSURE TEST
1. Reduce the fuel pressure in the fuel line.





2. Disconnect the high pressure fuel hose from the fuel rail.

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





3. Place the MD998742-01 adapter on the end of the fuel rail, then attach the fuel high pressure hose to the adapter using the bolts supplied with the adapter.





4. Attach one end of the fuel hose supplied with the MIT210196 to the quick-disconnect fitting on the MD998742-01 adapter. Attach the other end of the hose to the fuel pressure gauge.
5. Connect the (-) terminal of the battery.





6. Apply battery Voltage to the fuel pump check terminal and activate the fuel pump; then, with fuel pressure thus applied, check to be sure that there is no fuel leakage from the pressure gauge or the special tool connection part.
7. Start the engine and run at curb idle speed.
8. Disconnect the vacuum hose form the pressure regulator and clog the vacuum hose end. Measure the fuel pressure.

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

9. Measure the fuel pressure when the vacuum hose is connected to the pressure regulator:

Standard value: Approx. 270 kPa (38 psi) at curb idle

10. Race the engine repeatedly in two or three series. Then check that the fuel pressure does not fall when the engine is running at idle.





11. Check to be sure that there is fuel pressure in the return hose also (by gently pressing the fuel return hose with a finger while repeatedly racing the engine).

NOTE: There will be no fuel pressure in the return hose when the volume of fuel flow is not sufficient.

12. If the results of the measurements made in steps (8) and (9) above are not within the standard value, use the table below to determine the probable cause, and then make the necessary repair.
13. Stop the engine and check for change in fuel pressure gauge indication, which should not drop.
If the gauge indicafion drops, observe the rate of drop and determine and remove the causes according to the following table.
14. Reduce the internal pressure of the fuel pipes and hoses.
15. Disconnect the high pressure fuel hose and remove the fuel pressure gauge from the fuel rail.

Caution: Because there will be some residual pressure in the fuel pipe line, use a shop towel to cover so that fuel doesn't splatter.

16. Mount a new O-ring ih the groove at the end of the high pressure fuel hose.
17. Connect the high pressure fuel hose to the fuel rail, and tighten the screws to the specified torque.
18. Check for fuel leaks.
- Apply battery Voltage to the fuel pump check terminal to operate the fuel pump.
- With fuel pressure acting, check the fuel line for leaks.








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