C13 Engines for Caterpillar Built Machines Caterpillar

Fuel Pressure Is High

Usage:

Use this procedure to troubleshoot high fuel pressure. Use this procedure if one of the codes in Table 1 is active or logged.

Note: High fuel pressure may cause high fuel temperatures. Troubleshoot a code for high fuel pressure before troubleshooting a code for high fuel temperature.

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Table 1
Diagnostic Trouble Codes
CDL Code and Description	Comments
E096 (1) High Fuel Pressure - least severe (1)	The code is logged. The fuel pressure is above the trip point pressure.
E096 (2) High Fuel Pressure - moderate severity (2)	The code is logged. The fuel pressure is above the trip point pressure.
E096 (3) High Fuel Pressure - most severe (3)	The code is logged. The fuel pressure is above the trip point pressure.

Probable Causes

Codes
Fuel pressure sensor
Fuel lines
Fuel transfer pump
Fuel return pressure regulator

Recommended Actions

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Table 2
Required Tooling
8T-7860 Connector
110-6349 Fitting as
8T-0855 Pressure Gauge
6V-3990 Coupler

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Table 3
Engine RPM	Fuel pressure from Cat ET	Fuel pressure from the mechanical gauge
800
1800

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Table 4
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect Cat^® Electronic Technician (ET) to the service tool connector. B. Determine if a code is present.	Codes	Result: A code is present. Proceed to Test Step 2. Result: A code not in Table 1 is present. Repair: Troubleshoot the code. Refer to the proper troubleshooting procedure. If the problem is not resolved, proceed to Test Step 2.
2. Check the Fuel Pressure Sensor Note: Do not use the fuel sampling port (2) for measuring the pressure. A. Record the fuel pressure in Cat ET. Enter the data in Table 3. B. Remove the fuel pressure sensor. C. Install an 8T-7860 Connector into the port of the pressure sensor. D. Install the 110-6349 Fitting as onto the 8T-7860 Connector. E. Install a 8T-0855 Pressure Gauge onto a 6V-3990 Coupler. F. Install the 6V-3990 Coupler onto the 110-6349 Fitting as. G. After the pressure sensor is removed, a code for low fuel pressure will become active. After the sensor is reinstalled, reset all active codes and clear all logged codes by cycling the keyswitch to Off. H. Record the fuel pressure on the pressure gauge. Record the data in Table 3. The gauge value of the fuel pressure should be within 137 kPa (20 psi) of the fuel pressure reading shown in Cat ET.	Fuel pressure	Result: The fuel pressure is OK. Proceed to Test Step 3. Result: The fuel pressure is NOT OK. Repair: Replace the pressure sensor. If the problem is not resolved, proceed to Test Step 3.
3. Inspect the Fuel Supply Lines A. Visually inspect the fuel lines between the primary filter base and the inlet to the cylinder head. Also, inspect the fuel cooler, if equipped. Inspect the fuel return line from the head to the fuel tank. Inspect the lines for restrictions, pinching, and swelling.	Fuel supply lines	Result: The fuel lines and the cooler are OK. Proceed to Test Step 4. Result: The fuel lines and the cooler are NOT OK. Repair: Make the necessary repairs. If the problem is not resolved, proceed to Test Step 4.
4. Replace the Return Fuel Pressure Regulator	Fuel pressure regulator	Result: The regulator was replaced. If the problem is not resolved, proceed to Test Step 5.
5. Inspect the Relief Valve for the Fuel Transfer Pump Note: The spring must move freely.	Relief valve	Result: The relief valve is NOT OK. Repair: Replace the fuel transfer pump. Result: The relief valve is OK. Repair: Clean the relief valve and reinstall the relief valve.

If the problem is not resolved, contact your Technical Communicator (TC). The TC can confer with the Dealer Solution Network (DSN) for further assistance.