49545 Mercruiser STUD, EXHAUST MANIFOLD TO EXHIUST ELBOW (1 3/4")

Probable Causes
Monitoring system parameters
Inlet air restriction
Cylinder misfire
Valve lash settings
Low cylinder compressionRecommended Actions
Table 1
Troubleshooting Test Steps Values Results
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.
E841
through
E856
Result: An associated code is present.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: A code is present for an exhaust port temperature.
Proceed to the next step.
Result: No active codes
STOP
2. Check the Monitoring System Parameters
A. Ensure that the monitoring system parameters for the exhaust temperature module are set correctly.
B. Ensure that the monitoring system parameters for the exhaust port temperatures are set correctly.
wa
Parameters
Result: The module parameters are OK.
Continue with this step.
Result: The module parameters are NOT OK.
Repair: Refer to Troubleshooting, "Event Codes" for information that relates to the default parameters, ranges, and delay times of the monitoring system parameters that are for the exhaust port temperatures.
Result: The port temperatures parameters are OK.
Proceed to the next step.
Result: The port temperatures parameters are NOT OK.
Repair: Refer to Troubleshooting, "Event Codes" for information that relates to the default parameters, ranges, and delay times of the monitoring system parameters that are for the exhaust port temperatures.
If the problem is not resolved, proceed to the next step.
3. Check for Inlet Air Restriction
Note: Inlet air restriction can cause uneven exhaust port temperatures. Cylinders at the front half of the engine may have exhaust port temperatures that are lower than the exhaust port temperatures for the cylinders at the rear half of the engine by 10 to 20 °C (18 to 36 °F).
A. Measure the inlet air restriction for each turbocharger.
Restriction
Result: The inlet air restriction is OK.
Proceed to the next step.
Result: The inlet air restriction is NOT OK. An imbalance in the system is discovered.
Repair: In order to equalize the inlet air restriction for each of the turbochargers.
If the problem is not resolved, proceed to the next step.
4. Check for Operation with a Light Load
Note: Operation with a low load can result in low exhaust temperatures.
A. Operate the engine at low idle or near low idle in order to detect a misfire problem.
Misfire
Result: There is a misfire.
Repair: Troubleshoot the cause of the misfire. Refer to Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable".
Proceed to the next step.
Result: There is not a misfire.
If the problem is not resolved, proceed to the next step.
5. Check the Valve Lash Settings
A. Check the valve lash settings for the valves on the engine. Refer to Systems Operation/Testing and Adjusting, "Valve Lash - Adjust" for information that is related to adjusting the valve lash for the engine.
Valve Lash
Result: The valve lash is OK.
Proceed to the next step.
Result: The valve lash is NOT OK.
Repair: Reset valve lash. Refer to Systems Operation/Testing and Adjusting, "Valve Lash - Adjust" for information that is related to adjusting the valve lash for the engine.
If the problem is not resolved, proceed to the next step.
6. Check for Low Cylinder Compression
A. Measure the cylinder pressures of the suspect bank in order to check for problems that are related to compression.
Compression Check
Result: The cylinder pressure is NOT OK.
Investigate the cause of the low compression.
Repair: Repair or replace as necessary.