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Failure Causes and Solutions of Weichai Generating Engine

Jun. 15, 2019

This article continues to introduce the common faults and solutions of Weichai engine for power generation.

Weichai generating engine

5.7 Black smoke emits from air exhaust pipe.

Failure causes and features


Diesel engine works overload, and fuel burns insufficiently.

Reduce load.

Fuel injection pump flow is overlarge or non-uniform.

Adjust fuel injection pump and speed governor.

Injection pressure of fuel injector is excessively low, and fuel atomization is poor.

Adjust the injection pressure.

Fuel injection is too late, and there is fuel burning in exhaust pipe.

Adjust fuel supply advance angle.


Air filter is blocked, and air admission is unsmooth.

Remove the dust from the filter element or replace it.

Diesel oil used is of heavy type or of poor quality.

Use the diesel type specified herein.

5.8 Temperature of outlet water of diesel engine is too high.

Failure causes and features


Water pump fan belt is too loose, and water flow is too small.

Adjust the pulley tension or replace the belt.

Diesel engine works under overload condition for too long.

Reduce load.

Insufficient coolant.

Fill up with coolant.

Water pump capacity is inadequate, resulting in inadequate circulating water volume.

Check clearance between impeller and housing, and replace any defective impeller.

Water pump impeller is damaged.

Replace water pump impeller.

Cooling system is blocked.

Clean the cooling system.

Thermostat does not work.

Check the thermostat, and replace it, if necessary.

Water temperature gauge does not work.

Replace water temperature gauge.

Engine is poorly lubricated, giving rise to high oil temperature.

Check lubricating system or clean lubricant passage way.

5.9 Overlow oil pressure

Failure causes and features


There is inadequate oil in the oil pan.

Measure the oil level with oil level indicator. Refill oil to upper scale mark.

Oil pressure alarm does not work.

Replace oil pressure alarm.

Oil gallery is blocked.

Clean oil passage, and purge it with compressed air.

Oil pump suction filter screen is blocked.

Dismantle the dust screen, and clean it with diesel.

Oil filter is blocked, and safety valve does not work.

Clean filter or replace filter element, and adjust the safety valve as per specification.  

Main bearing and connecting rod bearing of diesel engine are worn and clearance is increased.

Overhaul or replace main bearing and connecting rod bearing.

Diesel engine is overheated, and oil temperature is high, and oil becomes diluted.

Reduce load, replace oil and reduce oil temperature.

Reduce load, replace oil and reduce oil temperature.

Replace gear or housing.

5.10 Excessive consumption of oil

Failure causes and features


Oil ring, once glued by carbon deposit or worn, will increase in clearance,   unable to scrape oil any more.

Clean oil ring, and replace it, if it is excessively worn.

Oil ring spill pore is blocked by carbon deposit.

Eliminate the carbon deposit in spill pore.

The oil is overfilled, and the oil is splashed excessively, part of which entering into the combustion chamber, and causing the exhaust pipe to give off blue smoke.

Drain part of oil, limiting the oil level to below upper scale mark of oil level   indicator.

Oil connection or gasket is leaky.

Tighten oil passage joints, and replace gasket.

5.11 Oil dilution and aging

Failure causes and features


Oil ring, once glued by carbon deposit or worn, will cause gas blowby or causing diesel to leak into the oil pan.

Clean piston ring, and replace it if necessary.

Cylinder head gasket is leaky.

Check or replace cylinder head gasket.

Cylinder head has cracks or shrinkage porosity, or is leaky.

Replace cylinder head.

5.12 Common Faults in Circuit

Failure causes and features


1. Dynamo does not charge or charges at excessively weak current.

Loose wiring joints of generator or storage battery

Check all the wiring joints, and do rust protection and insulation.

Slipping of belt

Adjust the tensioning of pulley.  

Generator failure

Check the generator.  

2. Dynamo current is too strong or dynamo heats up

Short-circuit between binding posts of armature rotor and magnetic field rotor of generator

Check or replace them.

Voltage adjuster failure

Check or replace them.

3. Voltage regulator resistor is burnt out

The positive and negative poles of storage battery are wired in an opposite way.

Correct the way of wiring.


The cut-off device fails, and the current flow reversely when the diesel engine   is running at low speed.

Overhaul or replace it.

4. The starter doesn’t rotate.

Fuse blowout

Replace the fuse and check the wiring to short-circuit.

Loose wiring joints

Remove the dirt, and screw up the joints.

Storage battery undercharged     

Overhaul and charge it.

Poor contact of carbon brush

Clean and grind with very fine sandpaper.

Internal short-circuit of starter

Dismantle, check and repair

5. Starter can rotate, but produces underpower

Poor contact of carbon brush

Clean and grind with very fine sandpaper.

Poor contact of joints or switch

Screw up all joints, remove dirt.

Storage battery undercharged

Overhaul and charge it.

Weichai Introduction

Weichai is China's largest and most internationally competitive auto parts and assembly system industry group. Founded over 60 years, it has been committed to exploring the application and development of engine frontier technology, continuously researching and developing higher-level engine products, and its engine power covers 30-10,000 horsepower. The products are widely used in trucks, buses, construction machinery, agricultural machinery, marine power, generator sets and other fields. Weichai has always been adhered to the core concept of green power and international Weichai, committed to providing global users with energy-saving and environmental protection general power. It has a full range of engines that meet the requirements of the national standards for non-road mobile machinery emissions. At present, Weichai has become the most reliable partner of Chinese construction machinery manufacturers. Power emission range from 3 liters to 32 liters, power range from 30 hp to 1300 hp, and meet all kinds of power needs in the construction machinery market.

Weichai generator set

1. Weichai land generator set power range: 20KW to 320KW (50Hz and 60Hz are available)

2. Weichai Baudouin series generator set power range: 350KW to 3000KW (50Hz and 60Hz are available)

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
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  • E-mail: sales@dieselgeneratortech.com
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