804346T 1 Mercury CARB REPAIR KIT (1 Per Carburetor)

Table 1
Event Codes
J1939 Code and Description CDL Code and Description System Response
157-17
Engine Injector Metering Rail #1 Pressure : Low - least severe (1) E398(1)
Low Fuel Rail Pressure The fuel rail pressure is below the trip point pressure for the programmed delay time.
The code is logged.
157-18
Engine Injector Metering Rail #1 Pressure : Low - moderate severity (2) E398(2)
Low Fuel Rail Pressure The fuel rail pressure is below the trip point pressure for the programmed delay time.
The code is logged.
Engine power is derated. Probable Causes
Diagnostic codes and event codes
Low-pressure fuel system
High-pressure fuel rail leakage
Fuel rail pressure sensor problem
Fuel control valve problemRecommended Actions
Table 2
Troubleshooting Test Step Value Result
1. Check for Codes
A. Connect Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Download the "Product Status Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes.
C. Determine if the diagnostic trouble code that directed to this procedure is present.
D. Look for active diagnostic codes that are associated with the system for the event code that directed to this procedure.
Codes
Result: An associated code is present.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: A 157-17 or 157-18 code is present.
Proceed to the next step.
Result: No active codes
STOP
2. Check the Low Pressure Fuel System
A. Use Cat ET to monitor the value for the "Fuel Pressure (absolute)" parameter while you operate the engine. Monitor the parameter at all engine speeds.
B. Ensure that the "Fuel Pressure (absolute)" parameter is greater than 250 kPa (36 psi) (gauge) at low engine idle and that the pressure is at least 450 kPa (65 psi) (gauge) with the engine at high engine idle.
At rated engine speed and load, the optimum performance and durability of the high-pressure fuel pump is realized if the inlet pressure for the fuel control valve is maintained at 650 kPa (94 psi).
Pressure
Result: The "Fuel Pressure (absolute)" is OK.
Repair: Proceed to the next step.
Result: The "Fuel Pressure (absolute)" is NOT OK.
Repair: Refer to Troubleshooting, "Fuel Pressure Is Low (Fuel Transfer System)" to troubleshoot the symptom.
If the problem is not resolved, proceed to the next step.
3. Check for High-pressure Fuel Rail Leakage
A. Refer to Troubleshooting, "Fuel Rail Pressure Leakage Is High".
B. Refer to Systems Operation/Testing and Adjusting, "Injector Bypass Fuel Flow - Test".
Leak
Result: An excessive leak was not found.
Proceed to the next step.
Result: An excessive leak was found and repaired.
If the problem is not resolved, proceed to the next step.
4. Check the Fuel Rail Pressure Sensor
A. With the engine shutdown, use Cat ET to check the value for the "Fuel Rail Pressure (absolute)" parameter. After the engine has been shut down for 10 minutes, the "Fuel Rail Pressure (absolute)" will be less than 5,000 kPa (725 psi) (gauge).
Note: If the pressure is not less than 5,000 kPa (725 psi) (gauge) after 10 minutes, vent the pressure from the fuel system. Refer to Systems Operation/Testing and Adjusting, "Fuel Rail Pressure - Release" for information.
Rail
pressure
Result: The sensor reports the pressure that is in the fuel rail is less than 5,000 kPa (725 psi) (gauge). The fuel rail pressure sensor and the electrical circuit are OK.
Repair: Proceed to the next step.
Result: The sensor reports the pressure that is in the fuel rail does not fall to less than 5,000 kPa (725 psi) (gauge). There may be a problem with the fuel rail pressure sensor or the electrical circuit for the sensor.
Repair: Perform the necessary repairs. Refer to Troubleshooting, "Sensor Signal (Analog, Active) - Test" for information that is related to testing the circuit.
If the problem is not resolved, proceed to the next step.
5. Monitor the Percent Fuel Position to Check the Fuel Control Valve
Note: Before proceeding, ensure that the fuel control valve and the fuel priming pump are powered. Check the circuit breaker.
A. Check for the proper operation of the fuel control valve.
1. Use Cat ET to check the value of the "
Percent Fuel Position" parameter under the following conditions:
- Engine shutdown
- Power to the ECM keyswitch input.
The "Percent Fuel Position" should read 0 %.
2. Run the fuel priming pump.
The "Percent Fuel Position" should read 25 %.
Percent
fuel
position
Result: The "Percent Fuel Position" readings were OK.
Repair: Proceed to the next step.
Result: The "Percent Fuel Position" reading were NOT OK.
Repair: Replace the fuel control valve.
Note: Before replacing, the valve ensure that the fuel control valve and the fuel priming pump are powered. Check the circuit breaker.
If the problem is not resolved, proceed to the next step.
6. Monitor the Related Parameters to Check the Fuel Control Valve
A. Start the engine and run at low idle.
B. Use Cat ET to monitor the values for following parameters for fuel control valve:
- "Fuel Actuator Position Command"
- "Throttle Position"
- "Desired Fuel Rail Pressure"
- "Fuel Rail Pressure"
Note: Do not confuse the following parameters to be the same:
- "Fuel Actuator Position Command"
- "Throttle Position"
For this application, the relationship between these parameters is not proportional.
C. Vary the engine speed and the engine load.
The following should closely match as the speed and load changes:
- "Fuel Actuator Position Command"
- "Percent Fuel Position"
Parameter
value
Result: The parameters do not closely match as speed and load are varied.
Repair: Replace the fuel control valve.
Result: The parameters closely matched as speed and load were varied.
Repair: Replace the high-pressure fuel pump.