Section 3.3 Test #2 Flow Test — At Fuel Injector

Section 3.3
Test #2 Flow Test — At Fuel Injector

Perform the following test set-up and test to determine the flow at the fuel injector:‪

Section 3.3.1
Test #2 Set-Up

For test #2 set-up, see Figure "Test Setup #2 Flow Test at Fuel Injector"

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 1. Washers‪

 2. Fuel Return Line‪

 3. Banjo Fitting‪

Figure 1. Test Setup #2 Flow Test at Fuel Injector

  1. Using the injector line socket (J-46371) , remove the injection line at cylinder #4.

    Note: When removing the injection line, the transfer tube thrust nut must be held in order to keep the line from twisting.

  2. Remove the fuel return line, banjo fitting and washers from the cylinder head at the same cylinder from which the injection line was removed. See Figure "Test Setup #2 Flow Test at Fuel Injector" , item A.
  3. Using the adaptor and seal rings from the fuel adaptor parts kit (J-46377-A) to install the fuel return line back onto the cylinder head. Tighten adaptor securely. See Figure "Test Setup #2 Flow Test at Fuel Injector" , item B.
  4. Install the injection line using the injector line socket (J-46371) . Torque injection line to 25 N·m (18 lb·ft).
  5. Connect an extension hose from fuel test kit (J-46377-A) to the adaptor and catch any fuel which leaks out of the return line in a container.

Section 3.3.2
Test #2

Perform the following:‪

  1. Open the fuel fill cap to release pressure in the fuel tank.
    warning

    PERSONAL INJURY

    To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

  2. Start the engine and run it at a slow idle, 600 to 650 rpm until the adaptor opening appears moist.

    If fuel or coolant flows out of the return line, see the causes listed in Table "Problem — Fuel Flows Out of the Fuel Return Line" , “Problem — Fuel Flows Out of the Fuel Return Line,” and correct the problem. Make any necessary repairs and/or replacements.‪

  3. Increase the engine speed to 2500 rpm. At most, drops of fuel should appear at the adaptor opening.

    If fuel or coolant flows out of the return line, see the causes listed in Table "Problem — Fuel Flows Out of the Fuel Return Line" , “Problem — Fuel Flows Out of the Fuel Return Line,” and correct the problem. Make any necessary repairs and/or replacements.‪

  4. Remove the adaptor and seal ring part of kit (J-46377-A) . Restore the fuel return line to the original installation, as removed. Tighten the banjo bolt to 40-50 N·m (30-37 lb·ft).
  5. Make sure the fuel fill cap is tightly closed and the vehicle has been restored to operating condition.

    Problem — Fuel Flows Out of the Fuel Return Line

    Possible Cause

    Remedy

    At one or more of the fuel injectors, the transfer tube is leaking, cracked, or incorrectly installed.‪

    Replace the damaged transfer tube(s), or install it correctly.‪

    One or more fuel injectors are leaking, cracked, or incorrectly installed.‪

    Remove and inspect the fuel injector(s). Replace if necessary.‪

    On one or more fuel injectors, the O-ring between the fuel injector and the heat isolator is leaking.‪

    Remove the fuel injector(s) and replace the O-ring(s).‪

    On one or more fuel injectors, the O-ring between the fuel injector and the cylinder head is leaking.‪

    Inspect the engine oil at the dipstick for the presence of fuel. Inspect all the fuel injectors, and especially their O-rings, for leaks. Remove the fuel injector(s) and replace the O-rings, if necessary. Replace the fuel injectorr(s) if cracked or otherwise broken, and install correctly.‪

    At one or more fuel injectors, the heat isolator is cracked, faulty, or not sealing properly.‪

    Remove and inspect the heat isolator(s). Replace if necessary.‪

    The cylinder head is cracked or there is cavitation in the oil chamber.‪

    Inspect the engine oil at the dipstick for the presence of fuel. Replace the cylinder head if necessary.‪

    Table 3. Problem — Fuel Flows Out of the Fuel Return Line


EPA07 MBE 900 DDEC VI Troubleshooting Guide - 6SE580
Generated on 10-13-2008

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