Common Faults and Solutions of Weichai Engine

There is no fuel in the fuel tank or switch of the fuel tank is not turned on.

Fill up the fuel tank, and turn on the switch.

Blockage of fuel pipeline or filter

Remove the oil pipe and filter, and clean or replace the filter elements.

There is air in the fuel system.

Eliminate air in the fuel system, and tighten up the oil pipe connector.

Fault of fuel injection pump or wrong   fuel supply timing.

Check the fuel delivery pump and fuel injection pump, and adjust fuel supply advance angle.

Fuel injection failure or bad atomization of fuel injector

Clean or grind the fuel injector pairs, and adjust fuel injection pressure.

Fuel injection failure or bad atomization of fuel injector

Clean or grind the fuel injector pairs, and adjust fuel injection pressure.

Overlow air temperature, diesel engine is too cold.

Heat the cooling water, and adopt preheating start-up.

Diesel is of poor quality or contains water.  

Use specified diesel; Clean the oil tank,   and replace diesel.

Air filter is blocked.

Remove the dust from the filter element, and replace the filter element, if necessary.

Muffler is blocked.

Eliminate carbon deposit or sundries from the muffler.

There is air in the fuel system piping and components.

Exhaust all air, and tighten the fuel line joints to avoid air leakage.

There is error in valve timing.

Check the gear mark, valve clearance and camshaft.

Fuel supply advance angle is wrong.

Check the gear mark, and adjust the fuel supply advance angle.

Injection pressure of fuel injector is inadequate, and fuel atomization is poor.

Adjust the injection pressure.  

Fuel supply to various cylinders is not non-uniform.

Adjust fuel supply uniformity of fuel injection pump.

The rated speed cannot be reached. 

Adjust position of speed control lever

Valve clearance is too small or is zero.

Adjust the valve clearance

Valve and valve seat have carbon deposit, are worn or poorly sealed.

Eliminate carbon deposit and grind valve and valve seat, and mill and grind the valve seat, if necessary.

Piston ring is worn, or has inadequate elasticity.

Replace the piston ring.

Piston ring is glued and jammed by carbon deposit.

Clean it in kerosene.

Cylinder sleeve and piston are worn and their distance is too large.

Replace cylinder sleeve and piston, or bore the cylinder and use enlarged piston.

Poor sealing of cylinder head gasket.

Tighten cylinder head bolts, or replace cylinder head gasket.

Fuel injector hole leaks air.

Check copper gasket, and reinstall the fuel injector.

Valve spring breaks off.    

 Replace valve spring.

Valve and valve guide are seized and jammed.

Clean it in kerosene; replace it if it is worn or deformed.

There is no diesel in the tank.

Refill the fuel tank.

There is air and water in the fuel   system.

Remove  the air in the diesel system, and drain off water at bottom of fuel tank, and replace fuel filter element.

Fuel filter is blocked.

Clean fuel filter or replace filter element.

Air filter is blocked.

Replace filter elements.

Piston is seized in cylinder.

Overhaul and replace piston and cylinder sleeve.

Speed governor does not work.

Stop the engine immediately, and remove fuel injection pump or speed governor, and overhaul the speed governor.

Fuel injection pump rod is jammed.

Stop the engine immediately, and overhaul the fuel injection pump.

Pump rod comes off.

Stop the engine immediately for inspection, and reinstall the pump rod.  

Rough explosion of fuel. There is ringing rat-tat in the cylinder.

Adjust fuel supply advance angle.

Fuel burns slowly, and there is “back fire” in exhaust pipe.

Clearance between piston and cylinder liner increases, making dumb noise of knock which sometimes sounds like beating of shovel.

If the sound weakens after cylinder stops for 3~5 seconds, it is proved. Stop the engine and repair or replace piston and cylinder liner.

Clearance between crankshaft and   crankshaft main bearing is increased, giving off periodic grave clash.

Listen to the sound near main bearing, after shutdown of cylinder, little change takes place, while working with full load, the sound gets more significant.Stop the engine and repair or replace the main bearing shell or thrust plate.

Clearance between crankshaft rod journal and bearing is increased, giving off blunt clash.

Listen and check near main bearing seat. And check one by one according to cylinder number at low speed. Stop the engine for overhaul.Replace the main bearing shell.

Clearance between piston pin and   connecting rod bush is too large.Making sound of "Dang dang", strong and sharp.

Listen to the sound on the upper part of left side of engine block, when speed and load rise, the sound gets stronger and more powerful, after stopping the cylinder, the sound gets weak. Stop the engine for overhaul, and replace connecting rod bushing.

Valve clearance is overlarge, giving off   “da, da” sound.

There is continuous sound on one side of cylinder close to valve, and it doesn't  change because of cylinder shutdown. Stop the engine, and adjust valve clearances.

Air valve impacts with piston head,   giving off ringing clash.

Listen to the sound close to the fuel injector, and check if there is vibration, and check the valve clearance and valve timing.