HOSE AS 3079008 - Caterpillar

Illustration 1 g02790939
Locations on the low-pressure fuel system (1) Fuel return to the secondary fuel filter (2) Secondary fuel filter base (3) Transfer pump inlet regulator (TPIR) (4) Transfer pump inlet regulator return portTransfer Pump Inlet Regulator (TPIR) Flow Test
Perform the following procedure:
Disconnect the TPIR return line from the drain port on the TPIR. Install a suitable blanking cap on the open port in the TPIR return line
Connect a temporary drain line to the drain port on the TPIR.
Place the end of the temporary drain line into a suitable calibrated container.
With the keyswitch in the ON position but the engine not running, use a suitable multimeter to measure the input voltage to the EFLP. Record the reading.
With the keyswitch in the ON position but the engine not running, measure the fuel flow from the temporary drain line. Refer to Illustration 2 for the minimum acceptable flow rate.
Illustration 2 g02485896
Minimum TPIR flow rate
Remove the temporary drain line from the drain port on the TPIR. Connect the TPIR return line to the TPIR.
If the fuel flow in Step 5 is greater than the minimum limit, proceed to "High-Pressure Fuel Pump".
If the fuel flow in Step 5 is below the minimum limit, proceed to "Return Pressure Relief Valve Test".Return Pressure Relief Valve Test
Use the following procedure to check the fuel flow through the return pressure relief valve in the secondary fuel filter base:
Disconnect the return line (1) from the secondary fuel filter base and install a blank on the line. Install a temporary line and a calibrated container to the filter base.
With the keyswitch in the ON position, measure fuel flow from the temporary line.
If the fuel flow is more than 400 mL/min (13.6 oz/min), replace the secondary fuel filter base. Refer to Disassembly and Assembly, "Fuel Filter Base - Remove and Install (Twin Secondary Fuel Filter)".
Remove the temporary line and reconnect the return line.
If the secondary fuel filter base has been replaced, attempt to start the engine. If the engine does not start, use the following procedure to check the fuel flow from the EFLP:
Disconnect the fuel inlet from the primary fuel filter. Place the open end of the disconnected line into a calibrated container.
With the keyswitch in the ON position, measure the flow from the fuel line. Refer to the Illustration 3 for the minimum acceptable fuel flow.
Illustration 3 g02527498
Minimum EFLP flow rate
If the fuel flow is more than 5% below the acceptable limit, replace the EFLP.
If the fuel flow is more than 5% above the acceptable limit, contact the Technical Communicator at a Caterpillar dealer.
If the fuel flow from the EFLP is within limits, proceed to "Check the Return Fuel Lines".Check the Return Fuel Lines
Make sure that the TPIR return line is not blocked or kinked.
If the TPIR return line is clear, confirm that the Electric Fuel Lift Pump (EFLP) is operating. Make sure that fuel lines between the EFLP and the TPIR are not blocked or kinked.
If the fuel lines to the TPIR are clear and the EFLP is operating,