Kubota WG1605-E3, Diagnostic Manual

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ECM SYSTEM
WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
1-24
Lack of Power, Sluggishness, or Sponginess
Checks Action
DEFINITION: The engine delivers less than expected power. There is little or no increase in speed, when partially applying the accelerator
pedal.
Preliminary Checks
• Refer to Important Preliminary Checks.
• Refer to the LPG / Natural Gas Fuel system, OBD System Check.
• Compare the customer’s vehicle, with a similar unit. Make sure the customer has an actual
problem. Do not compare the power output, of the vehicle operating on LPG / natural gas, to a
vehicle operating on gasoline, as the fuels do have different drive feel characteristics.
• Remove the air filter, and check for dirt or restriction.
• Check the vehicle transmission. Refer to the OEM transmission diagnostics.
• Verify the fuel tank has fuel.
Fuel System Checks
• Check for a restricted fuel filter, contaminated fuel, or improper fuel pressure. Refer to LPG /
Natural Gas Fuel System Diagnosis.
• Check for the proper ignition output voltage, with the spark tester.
• Check for proper installation, of the mixer module assembly.
• Check all air inlet ducts, for condition and proper installation.
• Check for fuel leaks, between the DSR, and the mixer.
• Verify that the LPG / natural gas tank manual shut-off valve is fully open.
• Verify that liquid fuel (not vapor) is being delivered to the DSR.
Sensor Checks
• Check the Heated Exhaust Gas Oxygen Sensor (HEGO), for contamination and performance.
• Check for proper operation of the MAP sensor.
• Check for proper operation of the TPS sensor.
Exhaust System Checks
• Check the exhaust system, for a possible restriction:
• Inspect the exhaust system, for damaged or collapsed pipes.
• Inspect the muffler, for signs of heat distress, or for possible internal failure.
• Check for possible plugged catalytic converter.
Engine Mechanical Check
• Check the engine for the following:
– Engine compression
– Valve timing
• Improper or worn camshaft. Refer to Engine Mechanical, in the Service Manual.
Additional Check
• Check the ECM grounds, for being clean, tight, and in their proper locations.
• Check the generator output voltage.
• Visually and physically, inspect all electrical connections, within the suspected circuit and/or
systems.
• Check the scan tool data.
KiSC issued 12, 2016 A