Home Products News Contact Us
Home > Supports > Diesel Engine > Shangchai W Series Engine Troubleshooting Guidelines

Shangchai W Series Engine Troubleshooting Guidelines

Dec. 11, 2017


This is the troubleshooting guidelines part of Shangchai W series engine operation and maintenance manual. 

I General Information

Be calm and careful when the engine has faults, analyze the feature of a fault and judge the cause of a failure according to the following principles.


1) If there is abnormal phenomenon during the operation of the engine, use see, hear, touch and smell to comprehensively judge which part or which system has problems.

See- to observe the readings of each instrument, and changes of the color of exhaust smoke, coolant temperature and oil pressure.


Listen-f -to listen to the sound of the movements of moving part and its change with a slim metal rod or screw-driver as stethoscope on the relevant surfaces of the engine.


Touch-to feel for the working condition of the valve train parts and the engine vibration with finger.


Smell-to smell abnormal engine odor


2) The engine should be stopped timely for inspection when the engine suddenly goes wrong or the cause of a failure  has been found and the failure will affect the normal engine operation. If it is difficult to identify the cause of a failure, reduce engine speed and keep the engine running at low-speed without load far observation and and inspection in order to avoid a serious failure.


3) When a failure is judged as a serious one or the engine suddenly stops, it should be disassembled for inspection and repair.


4) Failure causes especially big ones as well as solutions to the failures should be recorded in the log of the engine as a reference for next maintenance.


The common faults and correction methods listed in this chapter are only for reference. In practical work, it should be flexible to find out internal and external causes of malfunctions according to specific engine operation condition and practical experience, provide right remedy to eliminate failures.


II Troubleshooting Guidelines



Fault Mode


Fault Mode


Engine will not start


Oil temperature and consumption too high


Engine power output low



Coolant in lube oil


Abnormal noise and vibration



Coolant temperature too high





Coolant temperature too low


Abnormal oil pressure



Oil in coolant




Typical system or component fault Mode



Typical system or component fault Mode


Electrical system fault



Fuel feed pump fault


Fuel injection pump fault



Fuel injector fault


Governor fault



Turbocharger fault


III Details of Troubleshooting Fault Mode(No1 and No 2)

No 1. Engine will not start


Fault feature

Possible cause



The engine can not fire after being driven bu starter, and no fuel in the fuel pump return pipe

Malfunction of fuel system:

(1) Air in the fuel system

(2) Fuel liquidity affected because of cold weather.

(3) The fuel pipe is blocked

(4) The fuel filter is blocked

(5) The fuel feed pump can not supply or continuously supply fuel

(6) The position of governor control handle is not correct.

(7) Improper fuel injection pump timing

(8) Very small or no injected fuel flow or no fuel atomization


Remove air from the fuel system and refer to section 5.3 for the procedure.

Choose proper fuel specified in this manual based on ambient condition.

Check and clean the pipe

Clean the strainer and replace the fuel filter.

Check the inlet pipe for leakage and the inlet pipe.

joint strainer for blockage. If it does not work, check the inlet pipe and feed pump.

The handle should be placed to min. Stable idle speed. Let a professional serviceman adjust the control handle when required.

Check and adjust the fuel injection pressure to the specified value on a test stand. Replace the injector(s) if required.


Engine will not crank when the starting switch gets on


(1) The wire of circuit connects incorrectly or contact is not good

(2) Insufficient battery power


Check whether the wire connection is correct or reliable.

Charge battery, or adopt a battery with sufficient output or add some more batteries in parallel.

Repair or replace the carbon bush, clean the reverse surface by wood abrasive paper, and blowing-off, or regulate the spring pressure.

Disconnect the engine with driven equipment and barring the engine to check if the crank train rotate with difficulty due to bearing seizure of crankshaft, connecting rod or piston or wrong crankshaft gear timing.



There is no fire while the fuel injection is right, and there is fuel in exhaust pipe


Insufficient cylinder 

compression pressure:

(1) Over wear of piston ring or cylinder liner

(2) Leakage at valves


Replace the piston ring and replace the cylinder liner according to the ware condition.

Check the valve clearance, valve spring, valve guide and the sealing condition of the valve seat. Make replacement, repair or grinding if necessary.



Starting time is long and there is no fire


Too low of ambient temperature


Use cold starting aid according to ambient temperature.


No 2. Engine power output low


Fault feature

Possible cause



Power or speed does not go up after increasing the fuel supply


Failure of fuel system:

(1) The fuel pipeline broken, or leakage at the pipeline joints, fuel filter blocked or air in the fuel system.

(2) Not enough fuel, or water and impurity in the fuel tank.

(3) Incorrect fuel injection pump timing.

(4) Not enough fuel supply from the fuel injection pump.

(5) Poor fuel atomization or low injection pressure.



Replace the damaged fuel pipe, tighten the joints, clean the strainer, replace fuel filter, and priming the fuel system.

Make sure there is enough fuel in the fuel tank. Discharge water and sediments in the fuel tank. Change the fuel in the tank with clean fuel if necessary.

Check and adjust the fuel injection pump timing.

Check the fuel injection pump and replace it if required.

Let a professional serviceman inspect the injectors for injection spray and injection pressure, and make adjustment. Replace the injector(s) if necessary.



Higher exhaust temperature and poor smoke at normal working condition



Failure of inlet and exhaust system:

(1) Block of the air filter

(2) Leakage in the intake system

(3) Block of the exhaust pipe, the connection pipe too long, or with too small elbow, or with too many elbows

(4) Wrong valve clearance

(5) Wrong fuel injection pump timing


Clean the filter element and replace it when required.

Check the pipeline somewhere between the outlet of the compressor and the inlet of intake manifold for leakage and remove the leak source.

Remove the carbon deposit inside the exhaust pipe, reduce elbows to no more than 3 and increase across area.

Check and adjust the valve clearance and refer to Section of 5.3 for the procedure.

Check and adjust the fuel injection pump timing.


Poor engine performance at all speeds



Change of fuel injection pump timing


Check and adjust the fuel injection pump timing.



Engine overheat



(1) Ambient temperature too high

(2) The temperature of lube oil and cooling water are very high and the exhaust temperature is also high



Improve the ventilation condition and take a good temporary cooling measure if the ambient temperature is too high.

Check and repair the cooler and rediator, and remove the scale. Inspect the diameter of relevant pipelines for too small across areas.


Not only low power output and poor engine performance, but also as leak, black smoke from the intake pipe and knocking noise.


Failure of cylinder head group:

(1) Looseness of cylinder head nuts or the damage of the cylinder gasket due to gas leak from and engine block, especially flowing out from the cylinder head gasket during transit operation.

(2) Leakage at intake or exhaust valve(s)

(3) Valve spring(s) damaged

(4) Wrong valve clearance

(5) Leakage at fuel injector hole or the damage of injector copper washer.

(6) Insufficient compression pressure due to the seizure of piston ring or valve stem.



Tighten the cylinder head nuts to the defined torque. Replace the cylinder head gasket, and repair the joint plane if necessary.


Disassembly and inspect the intake and exhume valves, repair and grind. Replace the valve seat(s) or/and valve(s) if required.


Replace the damaged spring(s)


Check and adjust the valve clearance and refer to Section of 5.3 for the procedure.


Check and repair the damaged parts.


Replace the piston rings, pistons, cylinder, lines and valves. Make replacement if necessary.



Abnormal noise and drop the oil pressure


Seizure of the connecting rod bearing(s) and crankshaft



Check the large end of connecting rods for the side clearance as well as backward and forward movement. If the connecting rods cannot movement, repair the crankshaft pin and change the connecting rod bearing(s)



Drop of speed, decrease of inlet air pressure, air leak or abnormal noise, leak.

Fault of the turbocharger:

(1) Wear of the turbocharge bearing and contact of the blades of the compressor or turbine to their housings.

(2) Dirt and block of the compressor and air leak at inlet pipe(s)


Let a professional serviceman check the turbocharger. Make replacement if necessary.


Let a professional serviceman clean the compressor housing and impeller. And tighten the joint nuts and clamps.



 For other user manual details about Shangchai W series engine:

Task And Methods of Shangchai W Series Diesel Engine Maintenance

Changing Coolant And Cleaning Cooling System of Shangchai Engine




Contact Us
  • Add.: Room 601, Laboratory Building, No.2 Gaohua Road, Nanning, Guangxi, China.
  • Tel.: +86 771 5805 269
  • Fax: +86 771 5805 259
  • Cellphone: +86 134 8102 4441
                    +86 138 7819 8542
  • E-mail: sales@dieselgeneratortech.com
Follow Us

Copyright © Guangxi Dingbo Power Equipment Manufacturing Co., Ltd. All Rights Reserved | Sitemap

Update cookies preferences


Contact Us