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Engine Governor Fault And Fuel Injector Fault

Jan. 05, 2018

This is part five of Shangchai diesel engine troubleshooting guidelines. The content includes fault feature No. 13 governor fault and No. 14 fuel feed pump fault.

(13) Governor fault

 

 

Fault feature

 

 

Possible cause

 

Correction

 

 

Instability of engine speed (engine hunting)

 

 

(1) Non-even fuel supply of each cylinder.

 

(2) Carbon deposit and fuel dripping at fuel nozzle.

 

(3) Lose connecting pin of the rack.

 

(4) The camshaft endply is too large.

 

(5) Lose flying-weight pin due to wear.

 

(6) The clearance between the control rack and the control gear is too large or there is burr between them.

 

(7) The control rack or throttle lever does not move freely.

 

(8) There is air in the fuel system

 

(9) The flyweight of flyweight seat does not open freely.

(10) Low speed is not set properly.

 

 

Let professional serviceman readjust the supply flow of each cylinder.

 

Let professional serviceman clean and repair the nozzle assembly, or replace the nozzle assembly.

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

Let professional serviceman regulate it, or replace the fuel injection pump.

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

Prime the fuel system.

Let professional serviceman repair it, or replace the fuel injection pump.

 

 

The engine can not reach rated speed.

 

 

(1) Permanent deformation of the gobernor spring.

 

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

 

(3) The operation handle does not reach the max, speed position.

 

 

Let professional serviceman repair it. Or the fuel injection pump.

 

Refer to fuel injection pump fault for troubleshooting.

 

Let professional serviceman check and adjust the operation handle.

 

 

The engine can not reach idle speed.

 

 

(1) The operation handle does not reach the idle speed position.

 

(2) Slight seizure of the rack and ring gear.

 

(3) The low-speed settings is not proper.

 

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

Let professional serviceman adjust it.

 

 

The governor does not work and speed exceeds 110% of the rated speed (usually called flying away)

 

 

(1) speed is too high.

 

(2) Deadlock of control rack or throttle lever.

 

(3) Dropout of the pin connecting the rack and drag link.

 

(4) Dropout of the throttle lever screw.

 

(5) Break of speed governing spring.

 

 

Make emergency stop at once by cutting off fuel supply or air supply. Let professional serviceman check and repair it. Or replace the fuel injection pump if necessary.

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

Let professional serviceman repair it, or replace the fuel injection pump.

 

 

 

(14) Fault feed pump fault

 

 

 

Fault feature

 

 

Possible cause

 

Correction

 

 

Not enough fuel supply

 

 

(1) Wear or break of the check-valve.

 

(2) Wear of the piston.

 

(3) Fuel leak at the fuel pipe joints.

 

(4) Block at the fuel inlet joint strainer.

 

(5) Lack of fuel due to the piston seizure.

 

(6) Fuel leak at the transfer pump.

 

 

Replace the fuel transfer pump.

 

Replace the fuel transfer pump.

 

Re-tighten the joints.

 

Clean the strainer.

 

Replace the fuel transfer pump.

 

Check the fuel transfer pump, and replace the pump if necessary.

 

 

 

(15) Fuel injector fault

 

 

Fault feature

 

 

Possible cause

 

Correction

 

 

A little or no fuel injected.

 

 

(1) There is air in the fuel supply system.

 

(2) Seizure of the fuel injector nozzle.

 

(3) Abnormal fuel supply from the fuel injection pump.

 

(4) Oil leak at high-pressure fuel pipes.

 

(5) Wear of fuel injector nozzles.

 

 

Prime the fuel system.

 

Let a professional serviceman check and replace the nozzle assembly.

 

Refer to fuel injection pump fault for troubleshooting.

 

Tighten the pipe locknut and replace the pipes with crack, make replacement if required.

 

Let a professional serviceman replace the nozzle assembly.

 

 

Too low fuel injection pressure.

 

 

(1) Lose pressure regulating screw.

 

(2) Deformation or break of the pressure regulating spring.

 

(3) Seizure of needle valves.

 

 

Let a professional serviceman readjust the screw to the defined pressure and tighten the locknut.

 

Let a professional serviceman replace the injector spring.

 

Let a professional serviceman replace the nozzle assembly.

 

 

Too high fuel injection pressure.

 

 

(1) Pressure regulating spring force too high.

 

(2) Seizure of needle valves.

 

(3) Block of the injection holes.

 

 

Let a professional serviceman readjust the spring force.

 

Let a professional serviceman replace the nozzle assembly.

 

Let a professional serviceman check and clean the injection holes. Replace the injector if necessary.

 

 

Fuel leak at fuel injector.

 

 

(1) Break of pressure regulating springs.

 

(2) Damage of needle valve facing.

 

(3) Seizure of needle valves.

 

(4) Deformation of tightening cap.

 

(5) Poor contact between nozzle and injector body.

 

 

Let a professional serviceman replace springs.

 

Let a professional serviceman replace the nozzle assembly.

 

Let a professional serviceman replace the nozzle assembly.

 

Let a professional serviceman replace the caps.

 

Let a professional serviceman repair or replace the nozzle assembly. Replace the injector if required.

 

 

Poor fuel atomization

 

 

(1) decay of pressure regulating spring force or break of springs.

 

(2) Wear of fuel injector nozzle seat surface.

 

(3) There is impurity on the fitting plane of fuel injector nozzle assembly.

 

(4) Deformation or wear of nozzle assembly.

 

(5) Seizure of needle valve.

 

 

Let a professional serviceman replace the springs.

 

Let a professional serviceman repair or replace the nozzle assembly.

 

Let a professional serviceman clean the nozzles.

 

Let a professional serviceman replace the nozzle assembly.

 

Let a professional serviceman replace the nozzle assembly.

 

 

Fuel spray in kine or fuel dripping.

 

 

(1) carbon deposit at nozzle holes and block of injection holes.

 

(2) Wear of needle valve seat surface.

 

(3) Seizure of needle valve.

 

 

Let a professional serviceman clean the injection holes. Replace the nozzle assembly if necessary.

 

Let a professional serviceman replace the nozzle assembly.

 

Let a professional serviceman replace the nozzle assembly.

 

 

The surface of needle valve is burn or in blue-black.

 

 

The engine is overheating

 

Check the cooling system and do not over-load the engine for a long time. Let a professional serviceman check the nozzle assembly and make replacement if necessary.

 

 

 

For more Shnagchai diesel engine troubleshotting guidelines: 

Shangchai SC27G Series Abnormal Troubles

Solutions For Engine Abnormal Noise, Vibration and Smoke

Instructions For Engine Low Output and Abnormal Troubles


 


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