SUPPORT AS 4249904 - Caterpillar

Fuel Quality
Recent field experience indicates that fuel quality can possibly affect the characteristics of combustion of the air/fuel mixture. When you analyze a particular installation, the following parameters are important to know:
Low heat value
Methane number
Specific gravity
Wobbe IndexValve Lash Adjustments
It is important for the valve lash adjustments to be correctly made for the intake valve, the exhaust valve, and the gas admission valve at the normal maintenance intervals. Incorrect valve lash adjustments can result in a combustion process that is inefficient. The valve lash adjustment for the gas admission valve has the most impact on the combustion process. Improper valve lash adjustment for the gas admission valve will affect the calculations for controlling the fuel system. This can result in the following problems: improper tuning, incorrect calculation of fuel flow, incorrect air/fuel ratio and incorrect exhaust port temperatures.Fuel Correction Factor
The Fuel Correction Factor (FCF) is an indication of a change in the quality of the fuel. After the engine is correctly tuned, the FCF that is displayed on the CMS panel and on the DDT will be 100 percent. Any change in fuel quality will result in a change in the FCF. The FCF also affects the "Engine Load" parameter that is displayed. In order for the "Engine Load" parameter to be as accurate as possible, the FCF should be reading 100 percent. Adjust the "Fuel Energy Content" potentiometer until the FCF that is displayed is 100 percent. The engine should be in the "Combustion Feedback Mode" when the "Fuel Energy Content" potentiometer is adjusted. When no other mechanical problems and/or combustion problems exist, the displayed "Engine Load" will be as accurate as possible.Note: The adjustment of the FCF with the "Fuel Energy Content" potentiometer is not required on a regular basis. The value of the FCF can change as much as 20 percent without any effect on the performance of the engine. In order to better understand the loading conditions of the engine, the FCF is adjusted while the engine is in the "Combustion Feedback Mode".Prechamber Tuning
Proper prechamber tuning of the engine is critical for proper engine operation and performance. Accurate prechamber tuning requires the following items: a recent fuel analysis, a DDT for the engine and an emissions analyzer for the exhaust. The fuel analysis will determine the lower heating value (LHV) of the fuel. This LHV is used to set the "Fuel Energy Content" potentiometer that is on the front door panel of the ESS. The engine should be loaded to the expected operating condition. If the engine load is expected to fluctuate, the engine load should be set at a point that is midway between the lowest load and the highest load for the prechamber tuning. Once the loading condition is identified, the engine should be operated until normal operating temperatures are achieved. If there are no combustion problems or mechanical problems, the "prechamber tuning" can begin when normal operating temperatures are reached.The DDT is used to place the engine in "PC CAL" mode. The