Chery QQ6 (S21) / S12LHD. Manual — part 248
scratch is present on the cylinder wall.
Pearl overheating check if the spark plug type matches, and then replace with the spark plug
with lower heat value (rapid heat radiation).
11.6 Regular replacement and use overdue
The spark plug is the low-value consumption goods. Though cheaper compared with other
matching parts, its ignition performance directly affects the performance of the engine. Therefore, it
needs regular replacement. For the spark plug used in our vehicles, we suggest that you should
replace the spark plug at the following mileages: 10,000-15,000 km (single electrode);
15,000-25,000 km (multi electrode).
Ignition performance fall of spark plug will make fuel consumption rise and power drop off.
The economic loss caused by excessive fuel consumption unconsciously will even afford to
hundreds of new spark plugs. Use overdue makes the working condition of the engine poor in long
term and brings some damage to the engine.
11.7 Inspection and maintenance of the spark plug
The inspection items for spark plug mainly include carbon deposit, electrode burn through, gap,
and sealing and spark jump performances of the spark plug etc.
The electrode gap of the spark plug should be 0.7-0.9mm. Too small electrode gap will reduce
the breakdown voltage and weaken the spark intensity; while too big electrode gap will increase the
voltage required by the spark plug and cause spark out, especially when the ignition coil is aging and
the ignition system is in poor maintenance, spark out is more liable to occur.
Common failures of spark plug: fall in sealing performance, air leak and soot at the air leakage
position. The above failures can be inspected and judged through sealing performance test and spark
jump test. Both sealing performance test and spark jump test can be conducted on a spark plug
cleaning tester.
It is unscientific that some drivers and maintenance professionals remove the spark plug from
the engine, place it on the cylinder head and inspect if it is in sound conditions using high voltage of
the vehicle. In this test, the spark plug electrode is under an atmosphere other than a gas pressure of
over 800KPa, its working pressure. Therefore, spark jump of a spark plug under an atmosphere
does not indicate that it will also reliably produce spark jump under a high pressure conditions in the
cylinder.
It is required that carbon deposit disposal and proper adjustment of spark plug gap should be
done after a mileage of 10,000-15,000 km in its lifetime. When the temperature in cylinder rises, the
electrode gap should be increased properly. That is, increase the electrode gap in summer while
reduce it in winter. If the mixed air is strong, the electrode gap should be increased; otherwise,
decreased. In plain region, the electrode gap should be decreased while in plateau region, increased.
12. Carbon Canister Solenoid Valve Control
12.1 Function:
Carbon canister solenoid valve is a device used to enable the fuel steam in fuel tank to enter
cylinder to combust through control of ECU. Through controlling duty cycle of a solenoid valve,
ECU can accomplish open and close of the solenoid valve.
12.2 Working principle:
The canister control valve is composed of solenoid, armature iron and valve etc. There is a filter
net at the inlet. The airflow through the canister control valve at one hand depends on the duty cycle
of the electric pulse output of canister control valve by ECU, and at another hand depends on the
pressure difference between the inlet and the outlet of the canister control valve. The canister control
valve will be closed when there is not any electric pulse.
12.4 Installation attentions
See above installation drawing for connection among canister control valve, carbon canister and
intake manifold.
l In order to avoid transfer of solid borne noise, floating installation of the canister control valve
on the hose is recommended.
l During installation, make sure that the airflow direction meets the specification.
l Appropriate measures such as filtering and purge etc. must be taken to prevent such foreign
material as particles from entry into the canister control valve from carbon canister or hose.
It is recommended that a corresponding protective strainer (size of grid<50mm) should be
installed on outlet of carbon canister.
12.5. Failure effects and judgment method
l Failure effects: Failure of functions etc.
Reasons for general failure: corrosion or poor sealing performance etc. due to entry of foreign
material into inside of the valve.
l Maintenance precautions:
1. During installation, make sure that the airflow direction meets the specification;
2. In case of control valve failure due to black particle inside the valve body, when replacement
of the control valve is required, check the status of the canister;
3. During maintenance, try to avoid entry of such liquid as water and oil etc. into the valve;
4. In order to avoid transfer of solid borne noise, floating installation of the canister control
valve on the hose is recommended.
87# pin of main relay
Canister control valve
1 From fuel tank
2 Canister
3 Atmosphere
4 Canister control valve
5 To intake manifold
6 Throttle
Cross-section view of
canister control valve
Installation drawing of canister control valve
ΔP is the difference between environmental pressure
Pu and intake manifold pressure Ps
l Simple measurement method:
With the joint removed, turn the digital multimeter to Ohm shift, and then connect the two
meter pens respectively to both pins of the canister control valve. The rated resistance at 20
should
℃
read 26±4Ω.
13. Electronic Accelerator Pedal
13.1 Function:
The electronic accelerator pedal has cancelled the conventional throttle guy and the position of
accelerator pedal is fed back to ECU by means of electronic signal, through which ECU can
calculate and control the action of the electronic accelerator pedal. Two sets of Hall sensors are
integrated in the pedal; ECU can compare and analyze the two signals, if one signal is improper,
ECU will duly access the other signal and light the failure indicator.
13.2 Working principle:
The pedal is a Hall sensor. The fixed Hall generator and signal processing circuit are installed
on fixed mounting of the pedal. The two permanent magnets with different magnetic sheet thickness
act together with the pedal. When the pedal acts, the magnetic flux passing the Hall generator will
also change accordingly, the signal processing circuit will process these signals and then send them
to ECU.
13.3 Detection:
The relationship between the two signals of the accelerator pedal is that signal 1 is equal to
signal voltage.
At idle speed position, the voltage of signal 1 is 4.59 and that of signal 2 is 4.30. When the
pedal is at middle position, the voltage will be the minimum; when the pedal is at either end position,
the voltage will be the maximum.
14. Three-way Catalytic Converter
14.1 Function:
Three-way catalytic converter is used to convert the noxious gas in tail gas into such innocuous
gases as carbon dioxide and water etc. At 300-800
, the conversion efficiency of three
℃
-way
catalytic converter is maximum; with a temperature below this scope, the conversion efficiency will
be very poor, while, with a temperature above this scope, the three-way catalytic converter may be
burnt out. Three-way catalytic converter can exert better conversion efficiency only when the
oxygen sensor works. In control strategies of ECU, there are several protective modes for three-way
catalytic converter, and ECU can protect the three-way catalytic converter by regulating air-fuel ratio
and ignition advance angle.
15. Fan Control
15.1 Function:
In order to abstract heat from engine system and from condenser with A/C turned on, fan
control is affected by the signal to ECU sent by water temperature sensor; When water temperature
is high (above the threshold value set by ECU), the fan will run, and when water temperature is low
(below the threshold value set by ECU), the fan will also run; with A/C turned on, the fan will run at
low speed.
15.2 Composition:
DC electric motor double fan (high and low speed change).
15.3 Installation requirements:
The fan is installed between the rear of radiator and the engine, be careful when installing: not
to damage fin of fan blade, otherwise, running noise of the fan will increase, if serious, it may lead to
sharp fall of heat radiation effect of the engine.
15.4 Failure diagnosis:
Fan control circuit is a short or open circuit to ground;
The fan has failure itself;
Too loud fan noise;
Failure in power supply circuit of fan.
15.5 Troubleshooting:
First, validate whether it is a high speed fan system problem or a low speed fan system problem.
Provided that this is a fan control system problem, use a diagnostic tester to locate the failure point,
and then validate whether it is a short-circuit or a break in control circuit.
Failure symptom: the fan failure may result in rise of engine coolant temperature and poor
refrigeration of A/C system.
15.6. Fan Control:
Turn-on of low gear of fan:
1. Temperature of engine coolant: 96℃-102
;
℃
2. On request for A/C, the fan will start up;
3. When driving speed is too high, the fan will start up;
High speed startup of fan:
1. Engine coolant temperature sensor failure;
2. Air flow meter failure;
3. Engine coolant temperature exceeds 102
.
℃
Pins:
Main relay
High
speed
relay of fan
Low
speed
relay of fan
Brief sketch map of fan control
Fan motor
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