HARNESS AS-WIRING 3844336 - Caterpillar

Illustration 1 g03750256
Transfer Pump Inlet Regulator (TPIR) components
(1) Transfer Pump Inlet Regulator (TPIR)
(2) TPIR return port
Illustration 2 g02355128
Minimum TPIR flow rate in a 12 VDC system
Illustration 3 g02355130
Minimum TPIR flow rate in a 24 VDC system
Before performing the following fuel system tests, the engine must be run for a minimum of 30 minutes.Note: When performing the following fuel system tests, the Electric Fuel Lift Pump (EFLP) will only operate for 2 minutes unless the engine is running. If necessary, cycle the keyswitch in order to reactivate the pump.
Table 2
Troubleshooting Test Steps Values Results
6. 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 8.
Result: The fuel flow is less than the minimum limit.
Proceed to Test Step 7.
7. Transfer Pump Inlet Regulator (TPIR) Return Test
A. Make sure that the TPIR return line is not blocked or kinked.
B. Check that the Electric Fuel Lift Pump (EFLP) is operating correctly.
C. Make sure that the fuel lines between the EFLP and the TPIR are not blocked or kinked.
TPIR return
Result: A fuel line is blocked or kinked.
Repair: Clear the fuel line or replace the fuel line.
Result: The EFLP is not operating correctly.
Repair: Refer to Troubleshooting, "Relay - Test".
Result: All fuel lines are OK and the EFLP appears to be operating correctly.
Proceed to Test Step 8.
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
8. 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