Changchai V402 Series

Questions and Answers

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Denise SuttonAug 15, 2025
How to troubleshoot a Changchai Engine that does not start?
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  Whitney McdonaldAug 15, 2025
  If your Changchai Engine is not starting, it could be due to several reasons: * **Low starting speed:** Ensure the charging voltage is above 10 volts, tighten the connector, and repair the terminal if needed. * **Poor contact in the starter motor:** Repair or replace the carbon brush if there's poor contact between the carbon brush of the starter motor and the rectifier. * **Starter motor gear issue:** Move the flywheel to another position and check the starter motor installation to ensure it is parallel with the gear ring axis.
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Clarence WhiteAug 18, 2025
Why is my Changchai V402 Engine blowing black smoke?
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  elizabethmooreAug 18, 2025
  If your Changchai Engine is emitting black smoke, it could be due to: * **Injector issues:** The injector might have carbon blockage or a sticking needle valve. In this case, check, clean, repair, or replace the injector. * **Overload:** Reduce the load to stay within the specified range. * **Valve problems:** Check for inaccurate valve clearance or poor valve sealing, and fix any issues found. * **Air intake blockage:** Remove and clean the air filter if the intake pipe or air filter is blocked.
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nshepherdAug 21, 2025
What to do if Changchai Engine has insufficient power?
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  Timothy CastroAug 21, 2025
  If your Changchai Engine has insufficient power, consider these potential causes: * **Fuel filter blockage:** Clean or replace the diesel fuel filter or the fuel pump inlet pipe joint screen if it's blocked. * **Injector problems:** Replace the fuel injector if the pressure is incorrect or atomization is poor. * **Air in the fuel system:** Remove any air from the fuel system. * **Air filter issues:** Clean or replace the air filter element if it's not smooth. * **Valve leakage:** Inspect the valve clearance, valve spring force, valve guide wear, valve sticking, and valve sealing surface. Replace parts or grind the valve if necessary.
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moorebrittanyAug 25, 2025
Why is my Changchai V402 emitting blue smoke?
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  Charles WattsAug 25, 2025
  If your Changchai Engine is producing blue smoke, here are some possible causes: * **Worn piston ring:** The piston ring may be excessively worn or lack elasticity due to carbon accumulation, causing oil to enter the combustion chamber. Clean or replace the piston ring. * **High oil level:** Drain any excess oil if the oil level is too high. * **Incorrect air ring installation:** Ensure the second tapered air ring is installed correctly, with the side marked "up" facing upwards.
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rebeccastevensAug 28, 2025
What causes abnormal oil pressure in a Changchai V402 Engine?
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  Louis DanielsAug 28, 2025
  Abnormal oil pressure in your Changchai Engine can be due to several factors: * **Low oil level:** Add or replace oil if the pressure is too low. * **Leaks:** If there is oil leakage due to a ruptured oil pipe or loose pipe joint, weld or tighten the affected area. Replace the oil pressure gauge if it's damaged. * **Filter issues:** Replace the oil filter regulator spring if it's deformed or fractured. * **Oil pump problems:** Send the oil pump to the factory for repair or replacement if the clearance is too large, or replace the oil pump gasket if it's broken. * **Bearing clearance:** Inspect and replace if the bearing fit clearance is too large.
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davismichelleAug 31, 2025
What causes Changchai V402 overheating?
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  William MacdonaldSep 1, 2025
  If your Changchai Engine is overheating, it could be due to: * **Contaminated or insufficient oil:** Check and replace the piston ring if fuel is entering the crankcase or oil is entering the water. Replace the oil, check the oil level, check the cylinder head gasket, check the wear of the inner and outer rotor, and check and adjust the fit clearance of the bearings. * **Cooling system issues:** Inspect and replace the water pump impeller if it's damaged. Check the fan tape tension or replace the tape. Check the radiator installation position and the thermostat function. Clean the cooling system and water jacket. Check the water pump impeller clearance, fill the water, and replace the cylinder head gasket.
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Nicholas RussellSep 3, 2025
Why does my Changchai V402 Engine have excessive oil consumption?
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  Mckenzie DavisSep 3, 2025
  Excessive oil consumption in your Changchai Engine may be caused by: * **Incorrect oil viscosity:** Use the specified grade of engine oil. * **Worn components:** Replace or clean the oil return hole if the piston and cylinder liner are excessively worn or the piston ring groove oil return hole is blocked. * **Piston ring issues:** Clean, adjust, or replace the piston ring if the junction is worn or the gas ring is installed in reverse. * **Oil leaks:** Check or replace the relevant parts if there are oil leaks from the crankshaft oil seal or oil sump sealing surface. * **High oil temperature/pressure:** Lower the temperature and check and adjust the oil pump pressure limiting valve or oil filter regulator if the oil temperature and pressure are too high.
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Blake FreemanSep 7, 2025
What causes severe vibration in a Changchai V402 Engine?
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  waltersvalerieSep 7, 2025
  If your Changchai Engine is vibrating severely, consider the following: * **Fuel contamination:** Deflate, settle the diesel fuel, and replace it if there's water or air in it. * **Alignment issues:** Correct the alignment and tighten the support bolts if the diesel engine installation is misaligned or the bolts are loose. * **Wiring problems:** Check the wiring harness at each connector if there's poor contact in the electronic control system sensor or actuator harness.
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emaloneSep 12, 2025
What to do if Changchai Engine emits white smoke?
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  veronicaellisonSep 12, 2025
  If your Changchai Engine is emitting white smoke, it might be due to: * **Low oil injection pressure:** Replace the oil injector if the oil injection pressure is too low, atomization is poor, or there is oil leakage. * **Low cooling water temperature:** Increase the temperature of the cooling water if it's too low.

Summary

Preface

Important Pre-Use Precautions

Key safety and operational notes to follow before initial use of the diesel engine.

Maintenance and Specific Conditions

After-Treatment Device Considerations

Issues related to after-treatment devices and fuel/oil quality.

Fuel and Oil Quality Risks

Risks associated with using non-compliant diesel fuel and oils.

Safety Warnings and Notices

Danger and Warning Symbols

Explains danger and warning symbols related to fire and general hazards.

Notice and Caution Symbols

Explains notice and caution symbols regarding hot surfaces and burns.

Warning Markers and Safety Precautions

Marker Definitions

Defines the meanings of Danger, Warning, and Caution markers.

General Safety Operations

Crucial safety precautions for engine operation, including leak checks and battery handling.

Operational Safety Guidelines

Exhaust and Post-Operation Safety

Safety measures for exhaust gas handling and operating after drinking.

Maintenance Safety

Safety precautions during maintenance, like changing oil and handling hot water.

Disposal of Waste

Waste Handling Procedures

Guidelines for proper disposal of used oil and waste materials.

1 Main Technical Specifications

1.1 Engine Specifications

Detailed technical data for V402, 3M78, and M403TCI diesel engines.

1.2 Bolt and Nut Tightening Torques

Tightening Torque Values

Torque specifications for critical bolts and nuts on the engines.

2 Electronically Controlled Fuel Systems

2.1 Common Rail System Overview

Introduction to the electronically controlled common rail fuel injection system.

System Structure and Composition

Breakdown of components and structure of the common rail injection system.

2.1.2 Common Rail Operation Principle

Working Principle Explained

Explanation of the working principle of the common rail fuel injection system.

2.1.3 Control Strategy and ECU Functions

ECU Function Structure

Schematic of the Electronic Control Unit's functional components and signals.

2.2 Electrical System Wiring

Wiring Harness Importance

Information on the wiring harness and its importance for system operation.

2.3 Electronic Control System Usage

System Operation Guidelines

Key points for ensuring proper operation of the electronic control system.

3 Engine Use and Operation

3.1 Usage Precautions

Essential precautions for operating the diesel engine correctly.

3.2 Fuel, Oil, and Cooling Water

3.2.1 Fuel Guidelines

Selection of diesel fuel grade and refueling precautions.

Lubricant and Coolant Specifications

3.2.2 Lubricant Recommendations

Guidance on choosing engine oil based on viscosity and temperature.

3.2.3 Cooling Water Management

Advice on water treatment and antifreeze use for the cooling system.

Coolant Refilling and Scale Removal

Coolant Refill Precautions

Steps and safety measures for refilling the cooling system.

3.3 Pre-Start Checks

Inspection and Preparation Steps

Essential inspections and preparations before starting the engine.

3.4 Engine Startup Procedure

Startup Steps

Step-by-step guide for starting the diesel engine.

3.5 Operating Procedures

Monitoring and Control During Operation

Key parameters to monitor and control during engine operation.

3.6 Engine Parking

Parking Procedures and Precautions

Procedures and precautions for parking the diesel engine.

4 Engine Adjustments and Maintenance

4.1 Valve Clearance Adjustment

Detailed instructions for adjusting the valve clearance.

4.2 Fan Pulley Tension Adjustment

Method for adjusting the tension of the fan pulley belt.

4.3 Thermostat Precautions

Thermostat Handling Notes

Important notes and precautions related to the engine thermostat.

5 Engine Technical Maintenance

5.1 Daily Maintenance

Routine checks and maintenance tasks for daily upkeep.

5.2 First-Level Maintenance (100 Hours)

Maintenance tasks scheduled for every 100 hours of operation.

5.3 Second-Level Maintenance (500 Hours)

500-Hour Maintenance Procedures

Maintenance procedures required every 500 hours of operation.

5.4 Maintenance Instructions

Specific Maintenance Guidance

Specific guidance and instructions for performing engine maintenance.

5.5 Engine Sealing for Storage

Storage Sealing Procedure

Procedures for sealing the engine for long-term storage.

6 Engine Troubleshooting

6.1 Engine Fails to Start

Common reasons and solutions for engine starting failures.

Troubleshooting Engine Issues

6.2 Abnormal Oil Pressure

Causes and fixes for abnormal engine oil pressure.

6.3 Exhaust Smoke Analysis

Identification of exhaust smoke types and their corresponding solutions.

Troubleshooting Performance Problems

6.4 Insufficient Power

Diagnosing and rectifying issues causing insufficient engine power.

6.5 Abnormal Rattling Sound

Identifying and fixing the causes of abnormal rattling sounds.

Troubleshooting Operational Issues

6.6 Severe Vibration

Causes and remedies for excessive engine vibration.

6.7 Engine Overheating

Troubleshooting steps for engine overheating problems.

Troubleshooting Consumption and Speed Issues

6.8 Excessive Oil Consumption

Identifying and resolving causes of high oil consumption.

6.9 Dramatic Speed Increase

Causes and solutions for sudden, dramatic increases in engine speed.

6.10 Self-Parking Issues

Troubleshooting for problems related to the self-parking function.

Troubleshooting Oil Level and Annexes

6.11 Elevated Oil Level

Diagnosing and fixing elevated engine oil level issues.

Annex: Packing List

List of items included in the diesel engine package.