Kubota WG1605-E3, Diagnostic Manual

Page: 22 / 241

ECM SYSTEM
WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
1-12
Hard Start
Checks Action
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
• Refer to Important Preliminary Checks.
• Make sure the vehicle’s operator is using the correct starting procedure.
Sensor Checks
• Check the Throttle position (TPS) sensor.
• Check the Camshaft position (CMP) and Crankshaft (CKP) position sensors.
Fuel System Checks
• Check for fuel pump electrical circuit.
• Verify proper fuel pump pressure.
• Verify proper fuel rail pressure.
• Refer to the Gasoline Fuel System Diagnosis.
• Check Electrical connections at the injectors.
Ignition System Checks
• Check for the proper ignition voltage output.
• Verify that the spark plugs are correct.
• 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 the Crankshaft Position (CKP)
sensor.
2. Check for improper gap, debris or faulty connections.
Engine Mechanical Checks
• Check for the following:
– Vacuum leaks
– Improper valve timing
– Low compression
– Bent pushrods
– Worn rocker arms
– Broken or weak valve springs
• Check the intake and exhaust manifolds, for casting flash.
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. Refer to Restricted Exhaust System Diagnosis.
KiSC issued 12, 2016 A