Fuel Pressure Regulator: Testing and Inspection

1. Reduce the internal pressure of the fuel pipes and hoses.

High Pressure Fuel Hose Connection:

2. Disconnect the fuel high pressure 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.

Fuel Pressure Gauge Installed:

3. Set a fuel pressure gauge on the special tool, placing an adequate 0-ring or gasket between the gauge and special tool prevent fuel leaks.
4. Attach the special tool set in step 3 to the Fuel Rail between high pressure hoses.

Fuel Pump Check Terminal:

5. Connect a jumper wire to the Fuel Pump Check Connector and to the positive terminal of the battery to activate the Fuel Pump. With fuel pressure applied, check to be sure that there is no fuel leakage from the fuel pressure gauge and the special tool connection part.
6. Disconnect the jumper wire (from the terminal for activation of the fuel pump) to stop the Fuel Pump.
7. Start the engine and let it idle.
8. Measure the fuel pressure during idling.

Standard value: Approx. 235 kPa (34 PSI) at curb idle

Fuel Pressure Regulator, Vacuum Control Line Removed:

9. Disconnect the vacuum hose from the Fuel Pressure Regulator, and then measure the fuel pressure while using a finger to plug the end of the hose.

Standard value: 295 - 315 kPa (43 - 45 PSI) at curb idle

10. Check to be sure that the fuel pressure during idling does not decrease even after the engine is raced a few times.
11. Use a finger to gently press the fuel return hose while repeatedly racing the engine, and check to be sure that there is fuel pressure in the return hose also.

NOTE: There will be no fuel pressure in the return hose if there is insufficient fuel flow.





12. If the fuel pressure measured in steps 8 to 11 deviates from the standard value range, check for the probable cause by referring to the table above, and then make the appropriate repair.





13. Stop the engine and check for a change of the value indicated by the fuel pressure gauge. The condition is normal if there is no decrease of the indicated value within two minutes.

If there is a decrease of the indicated value, monitor the speed of the decrease, and, referring to the table below, determine the cause of the problem and make the appropriate repair.

14. Reduce the internal pressure of the fuel pipes and hoses.
15. Disconnect the fuel pressure gauge and the special tools from the delivery pipe.

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. Replace the 0-ring at the end of the fuel high-pressure hose with a new one.

17. After connecting the fuel high-pressure hose to the Fuel Rail, tighten the installation bolt at the specified torque.

Tightening torque: 5.0 Nm (3.6 ft.lbs.)

18. Check to be sure that there is no fuel leakage.
a. Apply battery voltage to the Fuel Pump Check Connector so as to activate the fuel pump.
b. With fuel pressure applied, check for leakage of the fuel line.