TUBE AS 4728176 - Caterpillar

Illustration 3 g02355130
Minimum TPIR flow rate in a 24 VDC system
Table 2
Troubleshooting Test Steps Values Results
9. Transfer Pump Inlet Regulator (TPIR) Flow Test
Refer to Illustration 1.
A. 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.
B. Connect a temporary drain line to the drain port on the TPIR.
C. Place the end of the temporary drain line into a suitable calibrated container.
D. With the isolator switch in the ON position but the engine not running, use a suitable multimeter to measure the input voltage to the EFLP. Record the reading.
E. With the isolator switch in the ON position but the engine not running, measure the fuel flow from the temporary drain line.
F. Refer to Illustration 2 or 3for the minimum acceptable flow rate.
G. Remove the temporary drain line from the drain port on the TPIR. Connect the TPIR return line to the TPIR.
TPIR flow rate
Result: The fuel flow is greater than the minimum limit.
Proceed to Test Step 11.
Result: The fuel flow is less than the minimum limit.
Proceed to Test Step 10.
Illustration 4 g02527498
Minimum EFLP flow rate in a 12 VDC system
Illustration 5 g02527518
Minimum EFLP flow rate in a 24 VDC system
Table 3
Troubleshooting Test Steps Values Results
10. EFLP Flow Test at the Primary Fuel Filter Inlet
A. Make sure the keyswitch is in the OFF position.
B. Disconnect the fuel inlet connection from the primary fuel filter head.
C. Install a suitable blank on the fuel inlet port on the primary fuel filter head.
D. Place the open end of the fuel inlet line in a suitable calibrated container.
E. With the keyswitch in the ON position, measure the input voltage at the EFLP. Record the result.
F. With the keyswitch in the ON position, measure the flow from the fuel inlet line. Record the result.
G. Check the recorded voltage and fuel flow on the graph in Illustration 4 or 5.
EFLP flow
Result: The fuel flow is below the minimum value for the recorded voltage.
Repair: Replace the EFLP. Refer to Disassembly and Assembly, "Fuel Priming Pump - Remove and Install ".
Result: The fuel flow is above the minimum value for the recorded voltage.
Proceed to Test Step 11.
11. Check the Return Fuel Lines
A. Make sure that the TPIR return line is not blocked or kinked..
B. 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.
Return lines
Result: The TPIR return line or the fuel lines between the EFLP and the TPIR are blocked or kinked.
Repair: Clear or replace the blocked line.
Result: The TPIR return line and the fuel lines between the EFLP and the TPIR are clear.
Repair: Replace the EFLP.
If the fault is still present, proceed to Test Step 12.
12. Low Compression (Cylinder Pressure)
A. Perform a compression test. Refer to Systems Operation, Testing, and Adjusting, "Compression - Test ".
Cylinder compression
Result: The results of the compression test are outside the specifications.
Repair: Investigate the cause