2008 GEELY CK engine

748. Idle speed too high at hot status
(1) Symptom
The engine runs at fast idle during cold start and remains fast idle at hot status, leading to excessively fast
idle.
(2) Causes and Troubleshooting
a. The initial idle value is not properly adjusted,
b. High system fuel pipeline pressure, need to be adjusted;
c. Water temperature sensor fault, repair or replace it;
d. Water temperature switch and thermostat fault, repair or replace it;
e. Idle control valve fault, repair or replace it;
f. Throttle is binding and not tightly closed, repair or replace it;
g. Fuel evaporation control valve is always open, repair or replace it;
h. Speed sensor fault, repair or replace it.
9. Idle fluctuation
(1) Symptom
when idling, the engine speed fluctuates.
(2) Causes and Troubleshooting
a. Intake pressure temperature sensor fault, repair or replace it;
b. Check valve is damaged and needs to be replaced;
c. Water temperature sensor , water temperature switch and thermostat is poorly coordinated, repair,
adjust and troubleshoot them;
d. Oxygen sensor fault, need to be replaced;
e. Spark plug poor connection, repair or replace it;
f. Idle control valve and its control circuit fault, repair or replace it;
g. Idle switch is not closed, need to be repaired.

7510. Engine overheat (Table 6)
Table 6Ite m Symptom Trouble shootingRepair or replace
Bad radiator hose Replace
Bad radiator tube strapSupplement welding, otherwise
replace it
Bad cylinder gasket Replace
Cracky cylinder blockRemedy with infiltration technology
or replace it
Poor water pump seal Replace the seal
Replace the anti-freeze liquid
Replace the thermostatBroken we ldSupplement weldingCorrosion result in pin holeFill the pinhole with clear coat,
otherwise replace it
Repair and dredge
Improve the ventilation
Repair or replace the water pump
Troubleshooting, replace the motor if
it is d a ma ge d
Replace
Repair and dredge
Repair or replace the oil pan if there
is o il le a k a ge , r e fill t he o il if it is no t
s up p le me nt e d in t imeCause
Ba d ra diator c over
Clogge d cooling tubePoor ventilationWater
le a ka ge
Anti-fre eze liquid not repla ce d
Bad thermostat
Radiator is
faultyWater
le a ka ge Insufficient
coolantF a ulty fa n vo lta ge
Disabled radiator temperature control
switch
Water jacket is clogged because of too much scale
I ns uffic ie nt e ngine o il ( o il le a k a ge o r d e la ye d filling)P oor
c ooling
Poor FanFaulty water pump

7611. General engine fault symptom and faulty area (Table 7)
Table 7
Unable to explode initially
Unable to explode completely
Difficult for cold start
Difficult for hot start
No fast ilde
Low idle speed
High idle speed
Rough ildling
Idle hunting
At urgent acceleration
When the accelerator pedal is releasec
During idling
Poor acceleration
Hunting during driving
Insufficient power
KnockInta ke a bosolute pre ssure
se nsor
ccccccc cc
Water temperature sensorcccc cc c cc c
Re volution spee d se nsor
c
Throttle valve position
se nsor
ccc ccccc
Vehicle speed sensor
c
Fuel pump system
cc c cc c
Fue l pre ssure regulator
ccccc c cccc
Fue l filte r a nd pipe line
cc c cccc
Injector
ccccc c ccc
Sta rte r signal
cc
Ignition c oil
ccc
Spark plug
cccc c cc c
High pre ssure ca ble
cc
Ignition timing
cc c c c cc
Igniter in the ECU
c ccc
Throttle valve
cccc c
Throttle valve bodycc c
Air leakage in the intake
air systemcc ccccc c
Air valve
ccccc
ECU powe r supply circuit
c
Ignition swtich
c
Ma in re la y
c
Fuel pump re laycPoor driving Difficult to start Poor idling Engine off
Power
supply
system Control
system
Fuel
system
Ignitio n
system
Intake
air
systemSuspect
AreaSymptom

77IV. Exhaust Pipe Discharges Gas with Abnormal Color (or odor)When there is failure in engine combustion system, the exhaust pipe discharges gas with abnormal color.
1. The discharged gas is thickly black
This is caused by incomplete combustion. Since the mixed air is too thick, the combustion is not complete and
part of the fuel is discharged without combustion, leading to decrease of engine power. At this moment, you
should check fuel pressure regulator, throttle position sensor, injector and ECU system and correct the
problems in time.
2. Exhaust is blue and stinks
This is caused by large amount of oil vapor mixed in the exhaust gas that enters in the cylinder and partici-
pates in combustion. One of the primary reasons is that the piston oil ring is dirty and damaged, and shall be
replaced; another reason may be the failure of valve oil seal or excessive clearance between the valve stem
and guide bush hole resulting in oil entering the combustion chamber for combustion, oil seal or valve guide
bush shall be replaced to resume normal condition.
3. Exhaust is white
This is caused by water or fuel vapor mixed in the exhaust. The primary reason is that cylinder head gasket
is damaged, resulting in slow infiltration of coolant into cylinder and the water vapor entry into the exhaust
pipe after combustion, cylinder head gasket shall be replaced to resume the normal condition.Section 3 Engine Noise Diagnosis and TroubleshootingAbnormal sounds generated during engine operation (e.g. knocking sound, chuckle, hiss, rattle) are called
noise.
Engine noise is primarily generated in valve train, connecting rod piston crankshaft components and other
accessory system. The following description discusses the diagnosis and troubleshooting of the noise gener-
ated in valve train and crankshaft connecting rod mechanism.I. Diagnosis and troubleshooting of the noise in valve trainvalve train consists of intake & exhaust camshaft , valve, valve bushing, tappetand counter gear.
1. camshaft noise
(1) camshaft end play is excessively big (normal intake camshaft : 0.030~0.085mm, exhaust camshaft : 0.
035~0.090mm) , when it exceeds 0.11mm and noise is generated, replace it;
(2) Camshaft bend is another cause for noise; it shall be aligned or scraped. ;
(3) Camshaft journal is excessively worn, resulting in big radial clearance between camshaft and bearing and
noise, replace it;
2. Valve group knock noise
(1) Valve noise is caused by excessive valve clearance, the valve spring seat flange is damaged and shall be
replaced;
(2) Valve spring knock noise is caused by broken valve spring. It shall be replaced;

78(3) Valve free movement noise is caused by dropped valve keeper or broken valve head. It shall be replaced;
(4) Noise between the intake & exhaust valve and valve bushing is caused by stagnation valve and bushing
that can not be closed, repair the bushing or replace it;
(5) Valve and valve seat can not be tightly closed and noise is generated, leading to abnormal engine operation.
Valve shall be grinded to fit, otherwise it shall be replaced.3. Gear noise is mainly caused by excessive wear of the gear which results in excessive clearance,generating the noise during the operation. The counter gear shall be replaced.

81Chapter 10 Engine Management UnitSection 1 System DescriptionEngine Control System generally consists of sensor, controller and actuator.
Sensor: convert the physical parameter of the device into electric signal (digital or analog) to monitor the
operating condition of the device and send these signals to the controller.
Controller: receive and process information sent from the sensor, and analyze the information to learn the
conditions of the device: use predefined control strategy and procedure, determine how to control the device
under current conditions; convert the decision into one or more orders and send them to the actuator. The
controller contains a microprocessor and stores pre-developed the programs or control software in the memory.
The controller can be regarded as the brain of the control system.
Actuator: receive orders from the controller, covert the electric signal into the action of the actuating ele-
ments (either action of electric element or mechanical movement). The actions of these elements will change
the operating conditions of the device and determine the operation and output of the device.
Large amount of information flows through the entire control system. Engine Control Unit learns the opera-
tion of the device from the information sent from the sensor, determines the approach and orders of the
control with the input and information stored by itself and ends up in sending the information about the orders
to the actuator.I. Engine Fuel System Electronic Control SystemEngine fuel system electronic control focuses on the quantified electronic control of the fuel, and actually is
the electronic control over the excessive air coefficient .
ECU controls the by controlling the fuel injection. When the engine is running, ECU receives the informa-
tion about the air flow from the sensor and determines the fuel injection by calculations to make the excessive
air coefficient of the mixed air reach the predefined value. The control order output by ECU is only a control
signal to trigger the injector. ECU output the pulse width and timing in this signal.
The pulse width of injection signal determines the fuel amount of the injection. The pulse is the function of the
following parameter. The input and output are modified into closed loop control.
ECU calculate the target - air fuel ratio.
Air flow value.
Other operating conditions of the engine, such as throttle position sensor, exhaust manifold oxygen sensor.
low feature of the injector.
Engine ignition system electronic control
The control of Engine Control Unit over the ignition includes ignition advance angle control, knock control and
ignition power control (dewell angle control).
The control over the ignition advance angle is the basic function of the ignition control. Ignition advance angle
= ignition advance angle basic value + correction.
The control over the ignition advance angle also relates to the operating conditions of the engine. The factor
varying with the operating conditions can be reflected by the correction factor.

82The control over the ignition advance angle is generally open loop control. But this open loop control is
different from the general open loop control, ECU test the knock signal with the knock sensor while control-
ling and outputting ignition advance angle orders in way of open loop. Once the knock occurs, it is converted
into closed loop control, and its feedback signal is knock sensor signal. Therefore, basically, it is also a closed
loop control.Section 2 System Component and Working PrincipleECU receives information from the sensors and sends control signals to actuators after processing and
analyzing these information. It plays a role of nerve center in the electronic control system.
ECU hardware consists of input level, micro-computer and output level (see figure 153).
Figure 153Ignition advance angle control Starting condition ¡ª fixed ignition advance angle
Running conditionSpecial controladvance angle basic value - determined by MAPadvance angle correctioninstantaneous correction
stable idle correction
air fuel ratio feedback correction
engine overheat correction
knock control
maximum advance/delayed angle controlother correction

83ECU microcomputer consists of microprocessor, memory, clock generator, timer, I/O interface and input
level A/D converter that are integrated in a large scale integrated circuit chip, that is SCM (Single Chip
Microcomputer).
1. Input level
The input signals from the sensor are pre-processed by the input level. The input signals are sent to protected
circuit first, sometimes through the signal converter and amplifier, and then sent to microcomputer.
The sensor signal is separated into switch type and analog type. Ignition on/off signal, camshaft position
signal, vehicle speed signal and A/C signal are switch type; Signals such as battery voltage, engine temperature,
intake temperature, airflow, intake manifold absolute pressure, throttle opening, excessive air coefficient,
knock, A/C refrigerant pressure are analog type. Analogy signal can only be processed by the digital micro-
computer after being converted into digital signal by A/D converter. Hence, data collection shall be made
first for analog signal, and the sampling shall be maintained also.
Speed and crankshaft position reference signal from the sensor is processed in a dedicated circuit to restrain
the interference pulse.
2. Microcomputer
The microcomputer of the engine electronic control unit is integrated in a single chip microcomputer, consist-
ing of the following:
(1) Microprocessor, microprocessor is also called as central processing unit (CPU), consisting of the following
three parts:
Arithmetic logic unit.
Register group.
Controller.
(2) System assembly, The data transferred among the internal sections of the single chip microcomputer
(SCM) is performed on the internal bus, while that between the SCM and other components is performed
on the external bus. The external bus is also called system bus. It is separated into data bus, address bus
and control bus.
(3) Memory, the memory is designed to store the binary data. The primary components of the memory are:
Memory.
Data register.
Address register, address decoder.
a. Memory controller
(4) A/D converter
(5) I/O interface.
(6) Clock generator.
(7) Timer
(8) CAPCOM unit.
(9) Watchdog timer.
(10) Interrupt system.