Kubota WG1605-E3 Diagnostic Manual page 31

WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
Checks
DEFINITION: The engine cranks OK, but does not start for a long time. The engine does eventually run, or may start, but immediately dies.
Preliminary Checks
Sensor Checks
Fuel System Checks
Ignition System Checks
Engine Mechanical Checks
Exhaust System Checks
Additional Checks
• Refer to Important Preliminary Checks.
• Make sure the vehicle's operator is using the correct starting procedure.
• Be sure that there is fuel in the fuel tank.
• Check to make sure the manual tank valve is fully open.
• Check the Crankshaft Position (CKP) sensor.
• Check the Camshaft sensor.
IMPORTANT
• A closed LPG / natural gas manual fuel shut off valve will create an extended crank, OR no
start condition.
• Verify the excess flow valve, in the LPG / natural gas manual shut-off valve, is not tripped.
• Check mixer module assembly, for proper installation and leakage.
• Verify proper operation, of the low pressure lock-off solenoids.
• Check for air intake system leakage, between the mixer and the throttle body.
• Check the fuel system pressures. Refer to the Fuel System Diagnosis.
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.
IMPORTANT
1. If the engine starts, but then immediately stalls, check Crankshaft Position (CKP).
2. Check for improper gap, debris, or faulty connections.
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. Refer to Workshop Manual
• Check the intake and exhaust manifolds, for casting flash.
• 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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Hard Start
Action
ECM SYSTEM
KiSC issued 12, 2016 A