803758 Mercury GUIDE

Table 1
J1939 Code and Description CDL Code and Description Comments
7021-10
Engine Fuel #2 Injector Metering Rail #1 Pressure : Abnormal Rate of Change E1467 (1)
Fuel Rail #2 Pressure Not Responding Fuel rail pressure has been detected as abnormal. Gas blending will not be enabled until the condition is resolved.
7021-15
Engine Fuel #2 Injector Metering Rail #1 Pressure : High - least severe (1) E1640 (1)
High Engine Fuel #2 Injector Metering Rail Pressure Fuel rail pressure has been detected at pressures greater than system requirements.
7021-16
Engine Fuel #2 Injector Metering Rail #1 Pressure : High - moderate severity (2) E1640 (2)
High Engine Fuel #2 Injector Metering Rail Pressure Fuel rail pressure has been detected at pressures greater than system requirements.
7021-18
Engine Fuel #2 Injector Metering Rail #1 Pressure : Low - moderate severity (2) E1639 (2)
Low Engine Fuel #2 Injector Metering Rail Pressure Fuel rail pressure has fallen below the minimum required pressure threshold.
Table 2
Associated Codes
J1939 CDL Troubleshooting Procedure
6646-15 E221 (1) Troubleshooting, "Fuel Pressure Is High (Gas Supply)"
6646-17 E222 (1) Troubleshooting, "Fuel Pressure Is Low (Gas Supply)" Electrical Checkouts on the Cat® Electronic Technician (ET)
Table 3
Component Electrical Checkout
Gas Shutoff Valve Engine Fuel Shutoff Valve #1 Control Override(1)
(1) The gas supply pressure must be 350 kPa (50 psi) or less to allow activation of the override.Gas rail pressure is constantly being monitored by the engine monitoring system. Prior to enabling gas blending, the system will initiate a system health check on the integrity of the gas fuel rail and associated components. During this time, the Gas Shutoff Valve (GSOV) is cycled ON then OFF to provide gas pressure to the rail. Observation in the rise and fall of system pressure is measured at this time. If conditions are detected which indicate there is a problem with the integrity of the gas fuel train, a 7021-10 Engine Fuel #2 Injector Metering Rail #1 Pressure : Abnormal Rate of Change is activated.Probable Causes
Codes
Shutoff valve and pressure regulator
LeaksRecommended Actions
Table 4
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: A -10 or -18 code is active or logged.
Proceed to Test Step 2.
Result: A -15 or -16 code is active or logged.
Proceed to Test Step 3.
2. Check for External Gas Leaks on the Engine
A. Ensure that there are no leaks on the engine gas system including gas rails, rear gas train, and gas admission valves.
B. Pressurize the gas rail with up to 700 kPa (100 psi) of Nitrogen, and use an ultrasonic leak detector or soapy water solution to identify locations where gas may be leaking.
Leaks
Result: A leak in the gas fuel train after the regulator has not been detected by the "Rail Integrity Check" function.
Proceed to Test Step 3.
Result: A leak in the gas fuel train after the regulator has been detected by the "Rail Integrity Check" function.
Repair: Repair or replace damaged gas fuel train components.
If the problem is not resolved, proceed to Test Step 3.
3. Check the Gas Shutoff Valve (GSOV) and Gas Pressure Regulator
A. Turn the keyswitch to the OFF position.
B. Close the Liquid Natural Gas (LNG) tank isolation valve.
C. Utilize chassis vent valve and safely purge gas from the gas supply line through the vent circuit to less than 350 kPa (50 psi).
Note: If required, nitrogen is recommended for pressuring the gas supply line up to 350 kPa (50 psi), not compressed air which may introduce moisture into the gas supply system.
D. Connect Cat ET.
E. Use Cat ET to monitor the status of the "Gas Supply Pressure" and "Gas Rail Pressure". Record the baseline pressure values.
F. Use Cat ET to perform the following override:
- Engine Fuel Shutoff Valve #1 Control override
G. Use Cat ET to monitor the status of the "Gas Supply Pressure" and "Gas Rail Pressure" after the GSOV was actuated open and closed with the override.
GSOV
Pressure Regulator
Result: After overriding the GSOV open, the gas rail pressure increased up to 180 7 kPa (26 1 psi) above the baseline pressure value.
Proceed to Test Step 3.
Result: After overriding the GSOV open, the gas rail pressure did not increase above the baseline pressure value.
Repair: The GSOV is not opening properly. Repair or replace the GSOV.
Verify that the repair eliminated the problem.
Result: The gas rail pressure is higher or lower than specification.
Repair: Adjust the gas pressure regulator. Refer to Testing and Adjusting, Fuel Pressure - Test (Gas System) for additional information. After adjusting the gas pressure regulator, the gas rail pressure now is within specification.
The gas rail pressure is not within specifications after adjusting the gas pressure regulator. Repair or replace the gas pressure regulator.
Verify that the repair eliminated the problem.
If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).