899912008 Mercury TAPPET, (3.158)

Recommended Actions
Note: If the problem only occurs under certain conditions, test the engine under those conditions. Examples of certain conditions are high engine speed, full load, and engine operating temperature. Troubleshooting the symptoms under other conditions can give misleading results.
Table 1
Troubleshooting Test Steps Values Results
1. Check for Active Codes and Logged Codes
A. Establish communication between Cat Electronic Technician (ET) and the Electronic Control Module (ECM).
B. Certain event codes may derate engine power. Monitor the diagnostic codes on Cat ET. Check for active diagnostic codes and logged codes (intermittent problems).
Codes
Result: A code is active or logged.
Repair: Troubleshoot any codes before continuing with this procedure.
Result: A code is not active or logged.
If the problem is not resolved, proceed to Test Step 2.
2. Programmable Parameters
A. If the ECM has been replaced, compare the values on the engine information plate to the following parameters from Cat ET.
- FRC Offset
- Full Load Setting (FLS)
- Full Torque Setting (FTS
B. Determine the type of throttle that is used in the application.
C. Program any parameters that may be associated with the throttle.
D. Program any parameters that may be associated with this troubleshooting procedure.
Parameters
Result: The parameters were program correctly.
Proceed to Test Step 3.
Result: The parameters were not programmed correctly and the engine had poor performance.
Repair: Reprogram the parameters and verify that they were programmed correctly.
If the problem is not resolved, proceed to Test Step 3.
3. Check for Cold Mode Operation (if applicable)
During cold mode operation, condensation may be present and is normal.
A. Cold mode is activated whenever the engine coolant temperature falls below a predetermined value. Monitor the status screen on Cat ET in order to verify that the engine has exited cold mode. Observe the reading for coolant temperature on Cat ET.
Cold Mode
Result: The engine is not operating in cold mode.
Proceed to Test Step 4.
Result: The engine is operating in cold mode.
Repair: This is normal operation. Return the engine to service.
4. Inspect the Electrical Connections
A. Check the associated wiring for damage, abrasion, corrosion, and for incorrect attachment on the following connectors:
- ECM Connectors
- Customer Connector
Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Connectors
Result: The connectors and wiring appear to be OK.
Proceed to Test Step 5.
Result: The connectors and wiring are NOT OK.
Repair: Repair the wiring and/or the connectors. Replace parts if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are coupled.
If the problem is not resolved, proceed to Test Step 5.
5. Check for an Intermittent Throttle Signal
A. Monitor the status for "Throttle Position" on Cat ET.
B. Verify that the status for "Throttle Position" is stable and that the engine is able to reach high idle speed.
Throttle Signal
Result: The status for "Throttle Position" is stable.
Proceed to Test Step 6.
Result: The status for "Throttle Position" is not stable.
Repair: Make the necessary repairs. Refer to Troubleshooting, "Throttle Position Sensor Circuit - Test", "Throttle Switch Control - Test", and "Speed Control - Test".
If the problem is not resolved, proceed to Test Step 6.
6. Monitor the Decelerator Pedal
A. Monitor the decelerator pedal on Cat ET.
Decelerator Pedal
Result: Verify that the decelerator pedal is operating properly.
Repair: Refer to Troubleshooting,"Deceleration Position Sensor Circuit - Test" for the proper troubleshooting procedure.
If the problem is not resolved, proceed to Test Step 7.
7. Unit Injectors
A. Perform the "Injector Solenoid Test" on Cat ET in order to determine if all of the injector solenoids are being energized by the ECM.
B. Perform the "Cylinder Cutout Test" in order to identify any injectors that might be misfiring.
Note: Refer to the procedure in Special Instruction, "Procedure for Troubleshooting and Cleaning the Oil Rail System for the Hydraulic Electronic Unit Injector".
Fuel Injectors
Result: The tests were successful.
Proceed to Test Step 8.
Result: The tests were NOT successful.
Repair: Remove the suspect injector, and install a new electronic unit injector. Refer to Disassembly and Assembly.
Ensure that the repairs have determined the problem. Refer to Troubleshooting, "Injector Solenoid - Test" and Troubleshooting, "Injection Actuation Pressure"
If the problem is not resolved, proceed to Test Step 8.
8. Injection Actuation Pressure
If service has recently been performed on the engine, air may be present in the injection actuation pressure circuit. Allow the engine to fully warm up and operate the engine under load in order to purge the air from the injection actuation pressure circuit.
A. Check the engine oil level. Engine oil supplies the injection actuation pressure circuit. The engine oil must be kept at the proper level for fuel injection.
B. Check the injection actuation pressure. Refer to the diagnostic functional test Troubleshooting, "Injection Actuation Pressure - Test".
C. Check the operation of the injection actuation control valve. Refer to the diagnostic functional test Troubleshooting, "Injection Actuation Pressure Control Valve Circuit - Test".
Injection Actuation
Result: The engine oil level is correct and the injection actuation system is operating properly.
Proceed to Test Step 9.
Result:The engine oil level is not correct and/or the injection actuation system is not properly operating.
Repair: Make the necessary repairs and return to service.
If the problem is not resolved, proceed to Test Step 9.
9. Fuel Supply
Refer to System Operation/Testing and Adjusting "Fuel System - Inspect" for additional information.
A. Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only.
B. Ensure that the vent in the fuel cap is not filled with debris.
C. Ensure that the fuel supply valve (if equipped) is in the full OPEN position.
Cold weather adversely affects the characteristics of the fuel. Refer to the engines Operation and Maintenance Manual for information on improving the characteristics of the fuel during cold-weather operation.
D. Check the fuel quality. Refer to Systems Operation/Testing and Adjusting, "Fuel Quality - Test" for the proper procedure. Check the fuel tank for debris or foreign objects which may block the fuel supply.
E. Check the filtered fuel pressure while the engine is being cranked. Refer to Troubleshooting, "Fuel Pressure Is Low" for the proper testing procedure.
Fuel System
Result: The fuel system is OK.
Proceed to Test Step 10.
Result: The fuel system is NOT OK.
Repair: Repair or replace damaged fuel system components.
If the problem is not resolved, proceed to Test Step 10.
10. Intake Manifold