JOINT ASSEM. 7D1985 - Caterpillar

The probable causes of high fuel pressure
Fuel pressure sensors
Fuel lines
Fuel transfer pump
Fuel return pressure regulatorUse this procedure in order to troubleshoot high fuel pressure. Use this procedure if the following event code is active. Refer to Troubleshooting, "Event Codes" for information about event codes. For information on the engine monitoring system, refer to Troubleshooting, "Engine Monitoring System".
Table 1
Diagnostic Trouble Codes
J1939 Code CDL Code Code Description Comments
94-16 E1218 (2) High Unfiltered Fuel Pressure The code is logged.
The fuel pressure is above the trip point pressure.
Table 2
Associated Diagnostic Trouble Codes
J1939 Code CDL Code
5584 E390 Complete the procedure in the order in which the steps are listed.
Table 3
Troubleshooting Test Steps Values Results
1. Determine the Code
A. Connect Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Download the "Warranty Report" from the engine Electronic Control Module (ECM) before performing any troubleshooting or clearing diagnostic trouble codes.
C. Determine if a diagnostic trouble code is present.
Codes
Result: An E1218 (2) or 94-16 code is present.
Proceed to Test Step 2.
Result: A code other than an E1218 (2) or 94-16 code is present.
Repair: Troubleshoot the code. Refer to the proper troubleshooting procedure.
Illustration 1 g03758116
(1) Fuel temperature sensor
(2) Fuel pressure sensor "A"
(3) Fuel pressure sensor "B"
(4) Fuel filter base
Table 4
Troubleshooting Test Steps Values Results
2. Check Fuel Pressure Sensor "A"
A. Record the unfiltered fuel pressure from Cat ET. Record the value in Table 6.
B. Remove fuel pressure sensor "A" (2).
C. Install a 5P-1318 Adapter into the port of the pressure sensor "A" (2).
D. Install the 123-0783 Fluid Sampling Valve Gp onto the 5P-1318 Adapter.
E. Install a 8T-0855 Pressure Gauge onto a 6V-3990 Coupler.
F. Install the 6V-3990 Coupler onto the 123-0783 Fluid Sampling Valve Gp.
G. Record the fuel pressure from the pressure gauge. Record the pressure in Table 6.
Pressure Sensor
Result: The gauge value of the fuel pressure is within 69 kPa (10 psi) of the unfiltered fuel pressure reading shown in Cat ET.
Proceed to Test Step 3.
Result: The gauge value of the fuel pressure is not within 69 kPa (10 psi) of the unfiltered fuel pressure reading shown in Cat ET.
Repair: Replace the pressure sensor. Verify that the problem has been resolved.
If the problem is not resolved, proceed to Test Step 3.
Table 5
Required Tooling for Pressure Sensor "A"
5P-1318 Adapter
123-0783 Fluid Sampling Valve Gp
8T-0855 Pressure Gauge
6V-3990 Coupler
Table 6
Engine RPM Unfiltered fuel pressure from Cat ET Fuel pressure from the mechanical gauge
800
1800
Illustration 2 g02041759
Fuel supply lines
Illustration 3 g02041781
Fuel return line
Table 7
Troubleshooting Test Steps Values Results
3. Inspect the Fuel Supply and Return Lines
A. Visually inspect the fuel lines between the primary filter base and the inlet to the fuel injection pump. Also, inspect the fuel cooler, if equipped. Inspect the fuel return line from the head t