Kubota WG1605-E3 Diagnostic Manual page 23

WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
Checks
DEFINITION: A surging or jerking that follows engine speed, usually more pronounced as the engine load increases, which is not normally felt
above 1500 RPM. The exhaust has a steady spitting sound at idle, low speed, or hard acceleration for the fuel starvation that can cause the
engine to cut-out.
Preliminary Checks
Ignition System Checks
Engine Mechanical Checks
Fuel System Checks
Additional Check
Checks
DEFINITION: The vehicle has a momentary lack of response, when depressing the accelerator. The condition can occur at any vehicle speed.
The condition may cause the engine to stall, if it's severe enough.
Preliminary Checks
Fuel System Checks
Ignition System Checks
Additional Check
Cuts Out, Misses
• Refer to Important Preliminary Checks.
• Start the engine.
• Wet down the secondary ignition system with water from a spray bottle and look/listen for arcing or
misfiring as you apply water.
• Check for proper ignition output voltage with spark tester.
• Check for a cylinder misfire.
• Verify that the spark plugs are correct.
• Remove the spark plugs in these cylinders and check for the following conditions:
– Insulation cracks
– Wear
– Improper gap
– Burned electrodes
– Heavy deposits
• Visually/Physically inspect the secondary ignition for the following:
– Ignition coil for cracks or carbon tracking.
• Perform a cylinder compression check.
• Check the engine for the following:
– Improper valve timing
– Bent pushrods
– Worn rocker arms
– Worn camshaft lobes.
– Broken or weak valve springs.
• Check the intake and exhaust manifold passages, for casting flash.
• Check the fuel system-plugged fuel filter, low fuel pressure, etc. Refer to Gasoline Fuel System
Diagnosis.
• Check the condition of the wiring to the fuel pump and injectors.
Check for Electromagnetic Interference (EMI).
• EMI on the reference circuit can cause a missing condition.
• Monitoring the engine RPM with a scan tool, can detect an EMI.
• A sudden increase in the RPM with little change in the actual engine RPM, indicates EMI is present.
• If the problem exists, check the routing of the secondary wires and the ground circuit.
Hesitation, Sag, Stumble
Refer to Important Preliminary Checks.
• Check the 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.
• Check for the proper ignition voltage output.
• Verify that the spark plugs are correct.
• Check for fouled spark plugs.
• Check for manifold vacuum or air induction system leaks.
• Check the generator output voltage.
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Action
Action
ECM SYSTEM
KiSC issued 12, 2016 A