990793 Volvo.Penta Snap ring

Table 1
J1939 Code and Description Comments
7320-0
Engine Multiple Cylinder Knock Level : High - most severe (3) The level of detonation has exceeded the trip point.
Maximum retardation of the timing was unable to control the detonation adequately during the number of ignition sparks that are allowed.
The engine performance may be affected by an adjustment of the timing to reduce detonation.
The code is logged. Probable Causes
Codes
Air/Fuel ratio
Engine overload
Cylinder misfire
Inlet air temperature
Detonation sensor
Coolant
Excessive deposits
Valve lashRecommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect the Cat® Electronic Technician (Cat ET) Service Tool 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 code is active or logged.
Proceed to Test Step 2.
2. Check the Air/Fuel Ratio
Note: An air/fuel mixture that is too rich will cause detonation. A change in the fuel energy content will change the air/fuel ratio.
A. Obtain a fuel analysis.
Note: If the quality of the gas is inconsistent, obtain several analyses over a time.
B. Enter the data into Caterpillar Software, LERW4485, "Gas Engine Rating Pro (GERP)".
C. Verify that the fuel supply pressure is adequate and stable.
D. Verify that the exhaust emissions are correct.
Air/Fuel Ratio
Result: The air/fuel ratio is OK.
Proceed to Test Step 3.
Result: The air/fuel ratio is NOT OK.
Repair: Use Cat ET to program the results for the "Fuel Specific Heat Ratio", "Fuel Quality", and "Gas Specific Gravity" parameters. Refer to Systems Operation, "Electronic Control System Parameters" for additional information.
Program the "Fuel Quality" parameter to the average value of the LHV. Adjust the engine operation according to Testing and Adjusting, "BTU and Precombustion Chamber Adjustments".
If the problem is not resolved, proceed to Test Step 3.
3. Check for Engine Overload
Note: When the load that is applied to the engine is too large, the engine will run in the lug condition. When the engine is running in the lug condition, engine rpm does not increase with an increase of fuel.
Load
Result: The engine is not being overloaded.
Proceed to Test Step 4.
Result: The engine is being overloaded.
Repair: Reduce engine load to an acceptable limit.
If the problem is not resolved, proceed to Test Step 4.
4. Check for a Cylinder Misfire
Note: Cylinder misfire can lead to detonation for an engine that is heavily loaded.
Misfire
Result: There is not a cylinder misfire.
Proceed to Test Step 5.
Result: There is a cylinder misfire.
Repair: Troubleshoot the cause of the misfire. Refer to Troubleshooting, "Engine Misfires, Runs Rough, or Is Unstable" for additional information.
If the problem is not resolved, proceed to Test Step 5.
5. Check for High Inlet Air Temperature
A. Check for high inlet air temperature.
B. Check for a restriction to the air flow through the aftercooler.
Air Temperature
Result: The inlet air temperature is OK.
Proceed to Test Step 6.
Result: The inlet air temperature is NOT OK.
Repair: Determine the reason for high inlet air temperatures. Repair or replace damaged components.
If the problem is not resolved, proceed to Test Step 6.
6. Inspect the Detonation Sensors
A. Check the detonation sensors torque.
Note: The detonation sensors torque to 15 3 N m (11 2 lb ft).
Note: The situation is unlikely to have a failed detonation sensor if a detonation event is only being detected at one cylinder. Detonation sensors are shared between two cylinders. A false detonation event due to a failed sensor would affect both cylinders being monitored by that sensor.
Sensor
Result: The detonation sensor torque is OK.
Proceed to Test Step 7.
Result: The detonation sensor torque is NOT OK.
Repair: Troubleshoot the circuit for the detonation sensors, if necessary. Refer to Troubleshooting, "Detonation - Test" for additional information.
If the problem is not resolved, proceed to Test Step 7.
7. Check for Coolant in the Cylinders
Note: Sometimes, detonation can occur if a solution of water and glycol leaks into a precombustion chamber and the coolant is burned. If a water/glycol solution is used, monitor the cylinder exhaust port temperature. If the temperature is higher than the average, inspect the cylinder for evidence of coolant leaks in the precombustion chamber.
Note: Significant leaking of any type of coolant will cause the cylinder to misfire.
Coolant
Result: Coolant is not in any cylinder.
Proceed to Test Step 8.
Result: Coolant is in a cylinder.
Repair: Investigate the cause of the condition. Make repairs, as needed.
If the problem is not resolved, proceed to Test Step 8.
8. Inspect for Excessive Deposits in the Combustion Chamber
A. Overfilling of engine oil can lead to deposits. Check the oil level.
B. Use a borescope to inspect the cylinders. Look for the following conditions:
- Deposits on the valve seats
- Deposits on the valve face
- Deposits on the cylinder walls that are above the upper limit of the piston stroke
- Signs of internal leaks
Note: Signs of internal leaks include excessive consumption of engine oil, blue smoke, and excessive detonation.
Deposits
Result: Deposits and/or signs of internal leaks are not found.
Proceed to Test Step 9.
Result: Deposits or signs of internal leaks are found.
Repair: Investigate the cause of the condition. Repair or replace damaged components.
If the problem is not resolved, proceed to Test Step 9.
9. Check the Valve Lash
Note: The valve lash can affect the performance of the engine.
Valve Lash
Result: The valve lash is NOT OK.
Repair: Reset the valve lash. Refer to Testing and Adjusting, "Valve Lash and Valve Bridge Adjustment (Gas Admission Valve Lash)" for additional information.
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).