COUPLING-PUMP DRIVE 8N1626 - Caterpillar

Use this procedure in order to troubleshoot an occurrence of a low fuel flow rate for the engine or use this procedure if the following event code is active. Refer to Troubleshooting, "Event Codes" for information about event codes. You must access the engine monitoring system on Caterpillar Electronic Technician (ET) in order to view the current trip points for these codes. For information on the engine monitoring system, refer to Troubleshooting, "Engine Monitoring System".
Table 1
Event Code
Description Conditions which Activate the Code System Response
E866(1) Low Gas Fuel Flow Rate The flow rate that is computed by the fuel metering valve does not match the fuel demand. The code is logged.
The alarm output is activated. Probable Causes
High fuel temperature
Faulty gas pressure regulator or low fuel supply pressure
Obstructions in the fuel supply
Fuel quality
Condensation in the gas supplyRecommended Actions
High Fuel Temperature
Measure the temperature of the gas that is entering the fuel metering valve. Compare the measurement to the reading for the fuel temperature on the Cat ET. Check Cat ET for an E223 High Gas Temperature.If the temperature on Cat ET is different, determine the reason for the faulty signal from the fuel metering valve.If the fuel temperature is high, determine the cause of the high fuel temperature. Check for proper operation of the equipment that treats the gas prior to the engine.Note: The fuel temperature is sensed by the fuel metering valve and communicated to the ECM via the CAN data link.If there is an active E223 High Gas Temperature, refer to Troubleshooting, "Fuel Temperature Is High".Perform the necessary repairs.Faulty Gas Pressure Regulator or Low Fuel Supply Pressure
Check the outlet pressure from the gas pressure regulator. The fuel metering valve requires a gas supply that is regulated to a pressure between 105 to 135 kPa (15 to 20 psi) (absolute pressure) for the gas supply.If the pressure of the gas supply is too low, adjust the gas pressure regulator in order to achieve the correct pressure.If the gas pressure regulator cannot be adjusted to the correct setting, repair the regulator or replace the regulator.Obstructions in the Fuel Supply
Check the fuel filter for restriction. Replace the fuel filter, if necessary.Inspect the screen inside the inlet of the fuel metering valve for cleanliness. Clean the screen, if necessary.Inspect the fuel supply lines to the fuel metering valve for obstructions. Clean the lines and make repairs, as needed.Check the Gas Shutoff Valve (GSOV) for proper operation. Verify that the valve is fully open when the valve is energized. Verify that the GSOV does not stick in a partially open position. Repair the GSOV. Replace the GSOV, if necessary.Fuel Quality
If the fuel energy content is too low, the fuel metering valve could demand an excessive supply of fuel.Obtain an analysis of the gas in order to determine the Low Heat Value (LHV). Program the "Fuel Quality" parameter to the actual value of the LHV.If the quality of the gas is not consistent, obtain several analyses over a period of time. Program the "Fuel Quality"