Kubota WG1605-E3 Diagnostic Manual page 30

WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
Checks
DEFINITION: The engine cranks OK, but does not start.
Preliminary Checks
Battery and Voltage Check
Control Module Checks
Sensor Checks
Fuel System Checks
Ignition System Checks
Engine Mechanical Checks
Exhaust System Checks
• Refer to Important Preliminary Checks.
• Check the battery charge condition.
• Check the battery cranking voltage, voltage less the 9.00 V are outside the parameters of
operation.
• Check Battery positive and negative cable ends for corrosion build up.
• Check the inline fuse in the ECM battery power circuit. Refer to Engine Controls Schematics.
• Check battery power, ignition power, and ground circuits, to the ECM.
Refer to Engine Control Schematics. Verify voltage and/or continuity, for each circuit.
• Crank sensor.
• Cam sensor.
IMPORTANT
• A closed LPG / natural gas manual fuel shut off valve, will create a no start condition. Check
the fuel supply line connection to ensure the Excess flow check valve has not set
• Check for air intake system leakage, between the mixer and the throttle body.
• Verify proper operation, of the low pressure lock-off solenoids.
• Fuel filter plugging.
• Check the fuel system pressures. Refer to the LPG / Natural Gas Fuel System Diagnosis.
• Check the low pressure fuel supply hose for restrictions and or blockage.
• Check for restrictions in the air intake system.
• Check for large vacuum leaks in the intake system.
• Check for proper mixer air valve operation.
• Check for exhaust pipe or catalyst restrictions.
NOTE
• LPG / natural gas, being a gaseous fuel, requires higher secondary ignition system
voltages, for the equivalent gasoline operating conditions.
• Check for the proper ignition voltage output.
• Verify that the spark plugs are correct, for use with LPG / natural gas.
• Check the spark plugs, for the following conditions:
– Wet plugs
– Cracks
– Wear
– Improper gap
– Burned electrodes
– Heavy deposits
• Check for loose ignition, coil connections, at the coil.
IMPORTANT
• The LPG / Natural Gas Fuel system works on a fumigation principle, of fuel introduction,
and is more sensitive, to intake manifold leakage, than the gasoline fuel supply system.
• Check for the following:
– Vacuum leaks
– Improper valve timing
– Low compression
– Bent pushrods
– Worn rocker arms
– Broken, or weak valve springs
– Worn camshaft lobes
• 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. Refer to Restricted Exhaust System Diagnosis.
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No Start
Action
ECM SYSTEM
KiSC issued 12, 2016 A