Foton Series Light Bus. Service Manual — part 9
OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS
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6.6 Technical maintenance for air intake system
6.6.1 Air filter
Detach air filter and take out element. Check filter appearance or if it is too dirty, distored, damaged or oil
stained. Replace if necessary.
Clean the air filter element by compressed air if the element is contaminated by dust. Blow the dust away by
compressed air from element inside.
●Caution:
(1) Do not blow the element from outside which will blow dust into the element.
(2) Do not use any detergent or water to wash the paper element.
Clean air filter case and air intake pipe inside.
Secure all parts firmly during mounting of air filter and element. Loose connection would let dirty air enter
cylinder.
For air filter maintenance of BJ491EQ1 multi-point electronic fuel injection please see vehicle service
manual or air filter service manual.
6.6.2 Air intake pipe
Check the tightness of the joint between air intake pipe and air filter, and remove the leaking immediately.
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Chapter 7 BJ491EQ1 Gasoline Engine Faults and Troubleshooting
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Chapter 7 BJ491EQ1 Gasoline Engine
Faults and Troubleshooting
7.1 Gasoline Engine Troubleshooting Summary
During gasoline engine operation, there will be some factors that gradually deteriorate its technical condition
such as part wear, distortion, incorrect use and technical service. When any of its technical data exceeds the
specification, engine has already had faults. Engine can not operate well until any fault on it has been eliminated.
With faults on it, engine’s power and economy will be reduced, and its emission will become worse too. Moreover,
Faults may cause parts early wear or even accident.
Some faults such as air in the fuel system, clogged filter, loose drive belt can be corrected after technical
maintenance and adjustment. However, others could not be elinminated just by the general maintenance and
adjustment methods. These faults includes damaged cylinder gasket, severe piston ring wear, valve cone face wear,
excessive bearing shell wear. Such faults can be removed only by dismantle- to-repair, or replacement parts and
components.
● Note:
(1) Remove the fault from the gasoline engine in time if any. To remove the faults, check and analyze
carefully, do not disassemble engine blindly.
(2) The operators should be familiar with the structure of the gasoline engine and its technical data, technical
requirements to dismantling and assembling. He must know how to perform service procedures and use service
tools.
(3) The complicated faults should be diagnosed and eliminated by the technical personnel using relevent
tools. If a user can’t determine the faults and has no required technical condition, he is suggested to approach to
FOTON authorized service station for help.
7.2 Diagnosis Basics -- Gasoline Engine Electronic Control Fuel Injection System
The gasoline engine electronic fuel injection system is sophisticated. Before faults diagnosis, the operator
should master the system’s principle, structure, service procedure and service tool application. First of all, he has
to determine if the faults acutally come from electronic fuel injection system. If there is a fault in gasoline engine
while malfunction indicator in instrument panel does not lit, the fault can not come from fuel injection system.
Fault diagnosis and check require special tool and tester. Operator should know them better before using
them, including knowing their function, structure and operating method. Common tools and tester includes circuit
test probe, multimeter and relevent testers.
To diagnose the faults in engine fuel injection system, you should be familiar with the following knowledge:
(1) The general information and basic principle of the electronic control fuel injection system.
(2) Performances of sensors, ECM and actuating devices, and their technical performance as well.
(3) The interface and terminal of the ECM and various sensors
7.3 Notes to Diagnosis-Gasoline Engine Electronic Control Fuel Injection System
7.3.1
DO NOT open the ECM cover, ECM is not serviceable. Once ECM cover has opened, it must be
damaged even if it seems to operate well for the moment.
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OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS
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7.3.2
During engine operation and service, never splash water on engine harnesses and sensors, which may
cause short circuit.
7.3.3
Faults on wire and its connections mainly include the open circuit, short circuit and grounding. The open
circuit is generally due to wire break-off and bad contact. Wire normally breaks off on connection position, thus
connection should be checked carefully. The bad contact may give rise to the terminal oxidation and the entry of
foreign materials. Wiring connects directly to body (grounding) causes short circuit. To check this, inspect if wire
conductor touches vehicle body or frame due to its insulating wrap has been damaged.
7.3.4
To check open circuit, unclip the ECM and related sensor connectors, and then measure the resistance
between the connecting terminals so as to confirm whether there is the open circuit or contact is damanged.
7.3.5
To check grounding or short circuit, detach wire’s two ends and measure resistance between the connecting
terminal and body (ground).Resistance that is more than 1Ω is acceptable.
7.3.6
After having turned ignition swithe on, never disconnect any 12V electrical connections, these connections
include cables of battery, idle speed control valve, injector, electric fuel pump, ignition system, ECM circuit, and
A/C wiring etc.
7.3.7
The digital multimeter should be used to check the sensors and ECM. Use other tester may damage the
sensors and ECM.
7.3.8
If “check engine” light keeps on during engine operation, find out the possible cause and remove it
A.S.A.P..
7.3.9
Check immediately if engine fuel economy become deteriorated. Use inferior fuel will damage the
oxygen sensor and three-way catalytic converter.
7.3.10
Once there is misfire happening in certain cylinder, intermediately stop driving and eliminate the faults.
Otherwise unburned gas mixture may burn in the exhaust system, which will quickly damage the oxygen sensor
and three-way catalytic converter. If it is difficult to remove such fault in a short time, disconnect the spark plug
from the misfire cylinder.
7.4 Gasoline EngineTroubleshooting Procedures
7.4.1 Unable or hard to startup
S/N Parts/components
Possible Cause
Solutions
1
Sensors
⑴ Poor connections -- coolant
temperature sensor, intake temperature
sensor
⑵ Incorrect crankshaft position sensor
clearance
⑶ Foreign objects and oil stains on
crankshaft pulley
⑷ ECM has not plugged in well
⑴ Reconnect the related harness
⑵ Check and adjust it to the proper
clearance
⑶ Remove foreign objects and oil stains
⑷ Check ECM connector.
2
Starting System
⑴ Battery voltage is too low
⑵ Battery poor connection
⑶ Fuse breaks off
⑷ Starter is failure
⑸ Ignition switch is failure
⑴ Recharge the battery as required
⑵ Clean the terminal posts and tighten the
battery cable
⑶ Replace the fuse
⑷ Repair or replace the starter
⑸ Repair or replace the ignition switch
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Chapter 7 BJ491EQ1 Gasoline Engine Faults and Troubleshooting
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S/N Parts/components
Possible Cause
Solutions
3
Fuel Supply
System
⑴ Fuel pump relay is failure
⑵ Fuel system pressure is insufficient
⑶ Injector is leaking
⑴ Replace the fuel pump relay or check the
connecting lead
⑵ Check the fuel level in tank and the
electric fuel pump working condition
⑶ Replace the injector
4
Ignition System
⑴ The ignition coil is failure
⑵ The high voltage cable is damaged
⑶ The spark plug is failure
⑷ The ignition system is poorly
connected.
⑴ Replace the ignition coil
⑵ Replace the high voltage cable
⑶ Adjust spark plug clearance, clear the
carbon deposit or replace the spark plug
⑷ Correctly connect the ignition system
5
Others
⑴ Valve has air leakage or is burnt out
⑵ Cylinder gasket is damaged
⑶ The intake manifold or vacuum pipe
is leaking
⑷ The piston, piston ring and cylinder
bore are damaged
⑴ Grind or replace the valve
⑵ Replace the cylinder gasket
⑶ Check the intake system, and remove the
air leakage
⑷ Repair or replace the piston, piston ring
or cylinder block
7.4.2 Engine Stalls
(Engine Rpm goes up and down constantly while throttle is opened)
S/N
Parts/components
Possible Cause
Solutions
1
Fuel System
⑴ Fuel is either enriched or too lean
⑵ The fuel system pressure is not
stable
⑶ The fuel filter is clogged
⑷ Fuel injector is clogged or fuel
leakage
⑴ Check whether the oxygen sensor and
fuel pressure regulator work normally
⑵ Check whether the electric fuel pump
works normally
⑶ Replace the fuel filter
⑷ Clean or replace the injector
2
Ignition System
⑴ The ignition coil secondary voltage
is too low
⑵ The spark plug electrode gap is
incorrect
⑶ The spark plug is burnt-out or has
serious carbon deposit
⑴ Check the ignition coil, replace if,
necessary
⑵ Adjust the spark plug electrode gap to
1.1mm±0.1mm
⑶ Clear away the carbon deposit or
replace the spark plug
3
Others
⑴ ECM ground lead is poorly
connected
⑵ The starting system voltage is not
within the range of 9 V to 16 V
⑶ The vacuum pipe is clogged or
leaking
⑷ The intake manifold is leaking
⑸ Poor valve sealing
⑹ Hydraulic tappet is failure
⑺ Excessive clearance between the
valve stem and valve guide
⑴ Confirm the ECM is connected reliably
⑵ Check whether the alternator output
voltage is proper
⑶ Check and clear the vacuum pipe
⑷ Check and remove the intake manifold
leakage
⑸ Grind the valve
⑹ Replace the hydraulic tappet
⑺ Replace the valve or valve guide
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OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS
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7.4.3 Engine Knock
S/N
Parts/components
Possible Cause
Solutions
1
Cooling System
⑴Coolant temperature is too
high
⑵ Water pump belt is loosening
⑶ The radiator pipes are clogged
⑷ Thermostat is failure
⑴ Add coolant and remove the leakage
⑵ Tighten the belt
⑶ Check and clear radiator pipes
⑷ Replace the thermostat
2
Coolant Temperature
Sensor
Coolant
temperature
sensor
output drifts
Replace the coolant temperature sensor
3
Gasoline
The gasoline octane number is
too low
Change to use specified gasoline
4
The ignition timing is incorrect
Check the sensor operation and connection
5
Others
⑴ Compression ratio is too high
⑵
Excessive
combustion
chamber carbon deposit
⑴ Check the sizes of related parts
⑵ Clear carbon deposit inside combution
chamber
7.4.4 Insufficent Engine Power
S/N
Parts/components
Possible Cause
Solutions
1
Intake System
The air filter is clogged
Replace the air filter element
2
Fuel Supply System
⑴ Fuel is contaminated
⑵ Fuel pressure is too low
⑴ Replace it with specified 93# or up lead
free gasoline
⑵ Check the electric fuel pump and vacuum
pipes or replace the fuel pressure regulator
3
Ignition System
⑴ The ignition coil secondary
voltage is too low
⑵ The ignition is abnormal
⑴ Check the ignition coil, or replace the
ignition coil if necessary
⑵ Check the wire and sensor concerned
4
Others
⑴ The exhaust system is clogged
⑵ The exhaust valve opens
abnormally
⑴ Check and remove the exhaust system
clogging
⑵ Check the exhaust valve opening condition,
or replace the valve, camshaft and other parts
and components concerned if necessary
5
Others
⑴ Poor ECM grounding
⑵ The power system voltage not
within the range of 9 V to 16 V
⑴ Check the cable and confirm that the ECM
can ground reliably.
⑵ Check whether alternator output voltage is
normal, or replace alternator and regulator if
necessary
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Chapter 7 BJ491EQ1 Gasoline Engine Faults and Troubleshooting
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7.4.5 Unsteady Engine Idle Speed
S/N
Parts/components
Possible Cause
Solutions
1
Sensor
⑴ Loose connectors -- intake
absolute pressure sensor, air
intake temperature sensor
⑵ The coolant temperature
sensor is failure
⑴ Check and connect all sensor connectors
again
⑵ Replace the coolant temperature sensor
2
Fuel System
⑴ Fuel injector has not plugged
in properly
⑵ The fuel system pressure is
not within 300kpa range
⑶ The injector is leaking or fuel
supply is insufficient
⑴ Check and connect the injector
⑵ Check the fuel system pressure, replace the
related parts if necessary
⑶ Check the injector, replace the injector if
necessary,
3
Ignition System
⑴ The ignition coil secondary
voltage is low
⑵ The high voltage cable is
leaking
⑶ The idle speed ignition
advance angle is not approx. 10º
⑷ The spark plug electrode
clearance is incorrect
⑸ The spark plug has carbon
deposit
⑹ The high voltage cable is
short circuit or has high internal
resistance
⑴ Replace the ignition coil if necessary
⑵ Replace the high voltage wire
⑶ Check the throttle position sensor, air
intake pressure sensor, and if necessary,
replace ECM
⑷ Check and adjust the spark plug clearance
⑸ Clear the carbon deposit, and if necessary,
replace the spark plug
⑹ Replace high voltage cable
4
Air Intake System
⑴ Air intake system is leak
⑵ The idle speed control valve is
failure
⑶ The throttle position sensor is
failure
⑷ The throttle opening is
incorrect
⑴ Check air intake system land eliminate
leakage
⑵ Replace the throttle valve body
⑶ Replace throttle position sensor
⑷ Check the accelerator cable and throttle
opening
5
Others
⑴ The cylinder pressure is
insufficient
⑵ The valve spring breakage or
excessive cam wear
⑴ Check and replace the related parts
⑵ Replace the related parts
6
Others
⑴ The power supply system
voltage is not within the range
9 V to 16 V, and idle speed
control valve fails to actuate
⑵ The ECM grounding is
incorrect
⑴ Check and repair the alternator and battery,
and if necessary, replace them
⑵ Correctly connect the ECM grounding wire
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OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS
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7.4.6 Highter Emission at Idle
S/N
Parts/components
Possible Cause
Solutions
1
Cooling System
The
coolant
temperature
is
abnormal
Check the cooling system and remove the
faults
2
Ignition System
⑴ The idle speed ignition
advance angle is not approx. 10º
⑵ The spark plug is failure
⑶ The high voltage wire is
failure
⑷ The ignition coil works
abnormally
⑴ Check if all sensors work normally
⑵ Check, clear and adjust spark plug
clearance
⑶ Check or replace the high voltage wire
⑷ Check, and if necessary, replace the
ignition coil
3
Air intake System
⑴ The vacuum leakage
⑵ The crankcase ventilation
valve is failure
⑴ Check and remove the vacuum leakage
⑵ Clean or replace the crankcase ventilation
valve
4
oxygen
sensor,
three-way
catalytic
converter are failure
⑴ Use the leaded gasoline or the
gasoline
with
phosphate,
sulphure and impurities beyond
the specified values
⑵ certain cylinder has misfire
⑶The
oxygen
sensor
and
three-way catalytic converter are
damaged
⑴ Use the clean lead free gasoline as required
⑵ Check the fuel passage, circuit to remove
the misfire faults
⑶ Replace the oxygen sensor and three-way
catalytic converter
5
Fuel System
⑴ Fuel is insufficient in fuel
tank
⑵ The electric fuel pump works
unsteadily
⑴ Refill the fuel
⑵ Check the electric fuel pump and its circuit,
and if necessary, replace the electric fuel pump
6
Others
Valve is leaking or grabbed.
Check the matching condition of the valve
stem and valve guide to ensure that the valve
is clogged. Or grind to repair the valve.
7.4.7 Excessive Fuel Consumption
S/N
Parts/components
Possible Cause
Solutions
1
Fuel Pipe
The fuel pipe or joint is leaking
Tighten all gasoline pipe joint
2
Air Intake/Exhaust
System
⑴ The air filter is clogged
⑵ The exhaust system leakage
⑴ Check, clean or replace the air filter element
⑵ Remove the exhaust system leakage
3
Ignition System
⑴ Poor sensor wire connection
⑵ The water temperature sensor,
oxygen
sensor,
air
intake
temperature sensor are failure
⑴ Reconnect all sensor plugs
⑵ Check, and if necessary, replace the sensors
4
Poor Compression
⑴ The spark plug is failure
⑵ The high voltage wire is
failure
⑴ Check or replace spark plug
⑵ Replace the high voltage wire
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Chapter 7 BJ491EQ1 Gasoline Engine Faults and Troubleshooting
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S/N
Parts/components
Possible Cause
Solutions
5
Poor Compression
⑴ Valve leakage
⑵ Failure hydraulic tappet
⑶ Weak valve spring
⑷ Cylinder gasket leakage
⑸ The piston ring is stuck or
broken
⑹ Excessive piston or cylinder
wear
⑴ Grind the valve
⑵ Check , rinse or replace the hydraulic
tappet
⑶ Replace the valve spring
⑷ Replace the cylinder gasket
⑸ Replace the piston ring
⑹ Repair or replace the related parts
6
Clutch
Poor clutch engagement, or
clutch slip
Check and adjust the clutch
7.4.8 Excessive Oil Consumption
S/N
Symptoms
Possible Cause
Solutions
1
Oil Leakage
⑴ The oil pan drain plug is loosen
⑵ The oil pan bolt is loosen
⑶ The oil pan gasket is damaged
⑷ The sprocket chamber cover
bolt is loosen
⑸ The cylinder head O-ring is
damaged
⑹ The crankshaft front/rear oil
seals are damaged
⑺ The pump bolts are loosen or
gasket damaged
⑻ Oil filter seat bolt is loosen or
gasket damaged
⑴ Tighten the oil pan drain plug
⑵ Tighten the oil pan fixing bolt
⑶ Replace the oil pan gasket
⑷ Tighten the bolt or replace the gasket
⑸ Replace the cylinder head O-ring
⑹ Replace the crankshaft front/rear oil seal
⑺ Tighten the inner fixing bolts or replace the
gasket
⑻ Tighten the oil filter fixing bolts or replace
the gasket
2
Poor Piston and
Cylinder Sealing
⑴ Oil ring has excessive wear or
gets damaged
⑵ Excessive wears on piston and
cylinder bore
⑴ Replace oil ring
⑵ Check or replace the piston and cylinder
block
3
Poor Valve
Sealing
⑴ The valve oil seal is damaged
⑵ Excessive valve stem and guide
wear
⑴ Replace the valve oil seal
⑵ Replace the valve and guide
4
Crankcase
Ventilation
System
The crankcase ventilation valve is
clogged
Check and clear up crankcase ventilation valve
5
Oil Consumption
is increasing
Gasoline engine operates at the
high speed under the small load
for a long time
Avoid that the gasoline operates at the high
speed under the small load condition for a long
time
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OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS
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7.4.9 Abnormal Sounds From Gasoline Engine
S/N
Possible Cause
Solutions
1
The hydraulic tappet is failure which
afftects the valve clearance
Check or replace the hydraulic tappet
2
Too loose piston pin which generates the tap
sound
Replace the piston pin or the piston
3
Excessive wears on piston, piston ring and
cylinder bore
Check and replace the piston and piston ring; bore cylinder
4
Excessive wear on connecting rod bearing
shell
Replace the connecting rod bearing shell
5
Excessive main bearing shell wear
Replace the main bearing shell
6
Excessive crankshaft thrust washer wear
Replace the crankshaft thrust washer
7
Too big cam axial clearance
Replace the camshaft thrust washer
8
Excessive
timing
chain
and
timing
sprocket wear
Replace the timing chain and timing sprocket
9
The chain tensioner is failure
Replace the chain tensioner
10
Excessive combustion chamber carbon
deposite
Clear the combustion chamber carbon deposite
11
The gasoline specification does not conform
to the requirements
Use the specified gasoline
7.4.10 Engine Overheat
S/N
Possible Cause
Remedies
1
Insufficient Coolant
Add the coolant as required
2
Fan belt is loose or damaged
Adjust the tension of fan belt or replace the belt
3
Water pump is failure
Check and repair the water pump or replace the water
pump
4
Thermostat is failure
Replace the thermostat
5
Radiator, cylinder block, cylinder head and
pipes & passages are clogged or leaking
Clean, repair or replace the related parts
6
Silicone oil fan clutch is failure
Check and replace the silicone oil fan clutch
7
Ignition timing is too late
Check the ignition timing
8
Engine oil level or viscosity is low
Refill or change oil as required
9
Excessive
cylinder
head
combustion
chamber carbon deposite
Remove the combustion chamber carbon deposite
10
Exhaust system is clogged
Clear or replace the exhaust system parts and components
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Chapter 7 BJ491EQ1 Gasoline Engine Faults and Troubleshooting
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7.4.11 Engine Oil Pressure Too Low
S/N
Possible Cause
Remedies
1
Oil leakage
Check or replace the related parts
2
Oil level or viscosity is low
Refill oil or replace oil as required
3
Oil temperature is too high
Cool the gasoline engine, check and repair the cooling
System
4
Oil pump pressure-limiting valve is failure
Check and repair the oil pump pressure-limiting valve
5
Oil pump is failure
Check and repair the oil pump or replace the oil pump
6
Oil strainer is clogged, connecting pipe
leakage
Clear oil strainer, and tighten the pipe joint
7
Oil filter is clogged
Replace the oil filter
8
Oil pressure gauge is failure
Replace the oil pressure sensing plug
9
Oil pressure gauge failure
Replace the oil pressure gauge
10
Excessive wears on main bearing shell,
connecting rod bearing shell or camshaft
bearing
Replace the bearing shell or bearing concerned
11
Serious oil leakage on rocker arm shaft or
chain tensioner
Check and tighten the related parts
7.4.12 Gasoline Engine Backfire
S/N
Parts/components
Possible Cause
Solutions
1
Ignition System
⑴ The spark plug electrode gap
is incorrect
⑵ The spark plug has carbon
deposit
⑶ The high voltage cable is
short circuit
⑷ The ignition coil secondary
voltage is insufficient
⑴ Adjust the spark plug electrode gap to
1.1mm±0.1mm
⑵ Clean the spark plug or replace the spark
plug
⑶ Replace the high voltage cable
⑷ Replace the ignition coil
2
Crankshaft Position
Sensor
Clearance between crankshaft
position sensor and crankshaft
pulley is incorrect
Check and adjust the clearance to the correct
value
3
Others
⑴ Valve leakage
⑵ Valve timing is incorrect
⑶ Air intake/exhaust pipe
leakage
⑴ Check the hydraulic tappet and valve
⑵ Check the valve and camshaft
⑶ Remove the air intake/exhaust pipe leakage
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OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS
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7.4.13
Engine Acceleration Delay or Lagging (Depressing accelerator pedal will not change speed when
driving at various speed, on in worst case, the gasoline engine even stalls)
S/N
Parts/component
Possible Cause
Solutions
1
Fuel System
⑴ The fuel system pressure is
low
⑵ The injector drive circuit is
failure
⑶ The electric fuel pump is
damaged
⑷ The fuel system is clogged
⑴ Check the fuel pump fuel-supply pressure,
check whether the fuel filter is clogged, and
check the fuel pressure regulator
⑵ Check the injector drive circuit
⑶ Replace the electric fuel pump
⑷ Replace the fuel filter, and clear the pipes
2
Ignition System
Certain spark plug or high
voltage wire is failure
Replace the spark plug or high voltage wire
3
Voltage is abnormal The power supply system voltage
is not within the range of 9V to
16V
Check the alternator and battery
4
Others
The throttle is grabbed
Clear the carbon deposit, and if necessary,
replace the throttle valve body
7.4.14 Engine Fuel Cut-off or Misfire
(the gasoline engine trembles during the acceleration, and the
sound of fuel after burning can be heard from the exhaust pipe when the engine operates at idle speed and low
speeds)
S/N
Parts/components
Possible Cause
Solutions
1
Ignition System
⑴ The spark plug clearance is
incorrect
⑵ The spark plug has carbon
deposit
⑶ High resistance
⑴ Adjust the spark plug clearance
⑵ Clear the carbon deposit or replace the
spark plug
⑶ Replace high resistance cable
2
Fuel System
⑴ The fuel pressure is incorrect
⑵ The fuel filter is clogged
⑶ The injector is failure
⑴ Check whether the electric fuel pump
operates normally, and check the fuel pressure
regulator
⑵ Replace the fuel filter
⑶ Replace the injector
3
Others
⑴ The valve timing is incorrect
⑵ Valve leakage
⑶ The valve spring is broken or
failure
⑷ The camshaft is failure
⑴ Check the valve timing
⑵ Grind the valve, and check the hydraulic
tappet
⑶ Replace the valve spring
⑷ Replace the camshaft
4
Electromagnetic
disturbance
Serious
electromagnetic
disturbance
Check the high voltage wire for leakage
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Chapter 8 Structure, Adjustment and Service of BJ483ZQB Diesel Engine
·131·
Chapter 8 Structure, Adjustment and Service of
BJ483ZQB Diesel Engine
8.1 Precautions on Service and Adjustment of Diesel Engine
8.1.1
Non-professional personnel never tries to dismantle to repair a diesel engine. The customers should contact
the dealers or service stations authorized by FOTON Motor Company.
8.1.2
The operators should be familiar with the structure of diesel engine and its technical data, component
assembly relationship and the technical requirements for disassembly/assembly, and understand the proper
methods for assembly/assembly and the maintenance tools using. Customer who does not have necessary
technical skills and conditions is suggested to contact the service stations authorized by Fonton Motor Company.
8.1.3
The disassembly procedure is generally conducted in the following order: from the outside to the inside,
and from the assy. to the components. To improve the assembly efficiency and ensure the correctness of the
assembly, note to check and make marks on parts when disassembly. Clean the components disassembled and
inspect them carefully. The components which can be reused should be sorted and stored by the assy.. The
precision components should be divided from the common ones, and stored in a clean container.
8.1.4
The assembly procedure is generally conducted in the following order: from the inside to the outside, and
from the parts to the components and then from the components to assy.. When assembly, pay more attention to
the installation dimension, orientation, fit clearance, tightening torque and etc. to avoid the neglected installation,
incorrect installation, the scuffing of component fitting surface, and the entry of foreign material into the inside of
the machine. Use proper wrench and fastening torque on bolts and nuts. Use fittings correctly according to
regulations, including cotter pins, spring washer, retraining washer etc. Beside, during assembly, note to cross
check parts codes with assembling marks to ensure right locations and motional relations among parts.
8.1.5
Ensure that the diesel engine is in the clean, good working conditions at all times. Before the disassembly
or assembly, clean or wipe parts to guarantee them clean and ensure the quality of assembly. The complicated
adjustment and maintenance should be conducted in doors to prevent the inside of diesel engine from being
contaminated by the environment.
8.1.6
Watch out personal injury due to moving parts or wrongly use of tools during dismantling or service.
8.2 Service and Adjustment of Diesel Engine
8.2.1 Tightening of Cylinder Head
The cylinder head is tightened to the cylinder block through the cylinder head gasket using 10 main bolts and
8 auxiliary bolts. To prevent the air leakage, the cylinder head bolts should have the sufficient tightening torque at
installation. The cylinder head bolts should be evenly tightened three times in the specified sequence using the
special torque wrench. The tightening sequence and the torque of the cylinder head main bolts are: 40 – 50 N·m
for the first time; 90 – 100 N·m for the second time; and 145 – 160 N·m for the third time. The tightening
sequence and the torque of the cylinder head auxiliary bolts are: 10 – 15 N·m for the first time; 25 – 35 N·m for
the second time; and 45 – 55 N·m for the third time. The tightening operation starts from the center and alternately
extends to its surroundings in sequence every time (see Figure 8-1), and at the last time, it should be tightened to
the specified torque.
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Figure 8-1 The Tightening Sequence of Cylinder Head Bolt
● Note:
(1) The turbocharged diesel engine adopts the integrated cylinder head gasket. During installation, there is
no foreign material in the outer part of the retainer; otherwise it may cause the blow-out of the combustion gas.
(2) When the air leakage from the diesel engine’s cylinder head gasket occurs, use a torque wrench to
check the tightening torque of the cylinder head bolts which should be tightened after the diesel engine has cooled
down.
(3) The cylinder head bolt is a kind of special high-strength bolt, and it is prohibited to substitute it with the
regular bolt.
8.2.2 Assembly of Cylinder Liner
The cylinder liner is with the dry-type structure. Its body is fixed together with the intermediate fixing main
bearing cap by the pin, flushing with the planes of front/rear main bearing caps. It interlinks with the main bearing
cap by main bearing cap bolts.
If the wear of inner surface of the cylinder liner is above 0.35 mm, replace it.
Clean the outer surface of the cylinder liner as well as cylinder bore wall before assembling a cylinder liner.
Do not apply lubricating grease on them to avoid that the grease affects the contact between the cylinder and its
liner as well as their heat dissapation. Apply uniform pressure to press cylinder liner into cylinder block.
8.2.3 Tightening of Main Bearing Cap Bolt
The tightening torque of main bearing cap bolt is 160 – 170 N·m. Tighen evenly in three times in sequence:
the first: 40 – 50 N·m; the second: 90 – 100 N·m; and the third: 160 – 170 N·m.
8.2.4 Assembly of Piston
The Figures 8-2 and 8-3 show the piston with the elliptical and cone-shaped head on which there are 2 gas
grooves and 1 oil groove. On the top face of piston, there is a forward arrowhead installation mark which points to
the front of diesel engine. In addition, the outside diameter grouping mark is engraved on the piston. Select the
piston group whose dimension group matches that of cylinder liner to install.
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Chapter 8 Structure, Adjustment and Service of BJ483ZQB Diesel Engine
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Figure 8-2 Piston and Connecting Rod
1-Piston; 2-Piston Ring; 3- Snap Ring; 4-Piston Pin; 5-Connecting Rod; 6-Connecting Rod Bushing; 7-Connecting Rod Cap;
8-Cumbustion Chamber
Figure 8-3 Piston and Piston Ring Structure
1-Barrel-Face Trapezoid Gas Ring; 2-Inner Chamfer Twist Type Gas Ring; 3-Spiral Spring Oil Ring
The piston pin seat locates in the middle section of the piston, and is used to support the piston pin. The
grooves at both ends of pin hole are used to install the snap ring which limits the piston pin axial movement.
There is an oil hole under the pin hole, which is used to collect the oil and lubricate the pin / seat friction surface.
Measure the wear of piston when repairing. Replace the piston if the wear of piston exceeds the standard
value.
● Note: The piston ring and piston should be replaced in pair.
8.2.5 Check and Assembly of Piston Ring
The piston ring is divided into gas ring and oil ring. Each piston 2 gas rings and 1 oil ring. The first gas ring
is a barrel-face trapezoid ring, the second gas ring is an inner chamfer twist type ring (the inner chamfer faces
upward when installation), and the third ring is a spiral spring oil ring (Figure 8-3).
The special tools are used to reassemble the piston ring (Figure 8-4). Install the spiral oil ring first, followed
by second and first rings.
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Figure 8-4 Installation of Piston Ring Using A Piston Ring Expander
Piston rings were set into cylinder liner under normal temperature. There should be proper gap at their opens
—so called “open gap”. Proper gap can help to avoid it being seized due to heat expansion, and reduce leakage
through gap to preserve energy and keep crankcase clean. The standard clearance values are as follows: first ring
0.25 – 0.40mm; second ring 0.25 – 0.40mm; oil ring 0.15-0.30mm.
Use a feeler to measure open gap after a piston has been put into a standard cylinder liner.
Wear on outer circle of a piston ring would enlarge open gap, air leakage would increase too. Replace ring
sets when gap exceeds limit.
The height clearance between ring and ring groove is called side clearance. Proper upper limit of side
clearance ensures ring could move in groove freely without sticking; and proper lower limit could help ring to
reduce oil pumping amount and restrain ring from moving up and down. Side clearance affects oil consumption.
Side clearance of each piston ring is as follows: 0.06 – 0.10 mm for the first ring; 0.04 – 0.08 mm for second
ring; and 0.02 – 0.06 mm for oil ring.
Use a feeler to measure side clearance after a piston ring has been put into its relating groove.
When to mount an oil ring, the lining spring connector should be installed opposite to the opening of oil ring
body.
After the piston ring has installed into the piston, the ring should move freely in the ring groove without
restriction. The opening positions of three piston rings should mutually stagger to each other.
Figure 8-5 Piston Ring Installation Position
8.2.6 Assembly of Piston Pin
The piston pin is fastened by a spring retaining ring. One end of the ring bends inwards. Use a long flat nose
pliers to snatch the bent on ring to take it out. No special tool is neede. (See Figure 8-6)
First Ring
Spiral Spring Opening
Spiral Spring Oil Ring
Second Ring
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Chapter 8 Structure, Adjustment and Service of BJ483ZQB Diesel Engine
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Figure 8-6 Remove spring retaining ring with nose pliers
Heat piston to 100
℃
– 120℃ before mounting piston pin into piston.
● Note: When to install piston pin retaining ring, check locating ring surface for any damage.
8.2.7 Assembly of Connecting Rod and Its Bolts
The connecting rod connects the piston with the crankshaft. The body of connecting rod and its big end cap
are attached in pair using the locating bolt, they are not interchangeable (see Figure 8-7).
Figure 8-7 Connecting Rod Assembly
1-Connecting rod small end bushing; 2-Connecting rod body; 3-Connecting rod bolt; 4-Connecting rod upper bearing shell
5-Connecting rod lower bearing shell; 6-Connecting rod cap; 7-Connecting rod nut
Apply lubricating oil on thread surface before mounting connecting rod bolts, and tighten two bolts in three
times. The tightening torque of the connecting rod bolt is 55 – 65 N·m.
Since the central plane of the connecting rod body misaligns with that of the connecting rod big end in axial
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