Kubota WG1605-E3 Diagnostic Manual page 34

WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
Checks
DEFINITION: The engine delivers less than expected power. There is little or no increase in speed, when partially applying the accelerator
pedal.
Preliminary Checks
Fuel System Checks
Sensor Checks
Exhaust System Checks
Engine Mechanical Check
Additional Check
Lack of Power, Sluggishness, or Sponginess
• 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.
• 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.
• 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.
• 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.
• Check the engine for the following:
– Engine compression
– Valve timing
• Improper or worn camshaft. Refer to Engine Mechanical, in the Service Manual.
• 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.
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Action
ECM SYSTEM
KiSC issued 12, 2016 A