2008 GEELY MK engine

Fault symptom
Flameout, poor idle speedChapter 9 Engine EFI SystemI. Outline This system includes sensor that detects engine functioning. Engine ECU utilizes sensors installed at differ-
ent parts of engine to measure various working parameters of engine, accurately control oil injection quantity
according to control procedure set in engine electronic control unit, so engine could work in optimum mode
under various operating conditions, i. e. optimal power output, the most economical oil consumption, optimal
exhaust emissions. Engine ECU is capable of start up control, idle speed closed-loop control, air fuel ratio
closed-loop control, canister control, transient operation control, angle of ignition control, knocking control, air
conditioning control, coasting fuel cutoff and overspeed fuel cutoff control, ternary catalyst heating and protec-
tion control, system self-diagnosis etc.II. Inspection of control element1. Manifold intake pressure temperature sensor
(1) The part to measure intake pressure is piezo type sensor, could provide controller with "load signal "
according to the difference between atmospheric pressure and manifold pressure; controller will supply 5V
voltage, and feed back 0-5V voltage to controller according to different intake pressures. The part to measure
intake temperature is NTC type (negative temperature coefficient) sensor, resistance changes with intake
temperature, this sensor conveys a voltage representing intake temperature change to the controller.
(2) Simple measuring method:
Temperature sensor part: (remove joint) turn digital multimeter
to Ohm position, two meter pens connect sensor 1 #, 2 # pinrespectively, rated resistance is 2. 5k ohm±5% at 20°C, correspond-ing resistance value may be measured from the above characteristic
curve. Simulation method may also be used for measurement, spe-
cific procedure is to use electric drier to blast sensor (pay attention not
to be too close), observe change of sensor resistance, here resistanceEngine EFI System-Engine EFI System5-120Possible cause
There is abnormal high voltage or reverse heavy current during useVacuum
unit is damaged during repair
Repair precautions: it is prohibit to use high pressure gas to impact vacuum unit during repair; when replace
sensor case of trouble, check whether generator output voltage and current is normal or not.1 2 3 4Manifold intake pressure temperature
sensor Intake pressure sensor feature cureIntake temperature feature curve
Output voltageAbsolute pressureTemperatureResistance

Fault symptom Possible cause
Poor speedup etc Man made fault1 2 3Throttle position sensorFault symptom Possible cause
Difficult to start Man made fault Repair precautions: pay attention to mounting position.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect
two meter pens with sensor 1 #, 2 # pin respectively, its resistance
value at room temperature is 2k ohm±20 %. Connect two meter pens
with 1 #, 3# pin respectively, rotate throttle, its resistance value shows
linear change with opening of throttle, while situation is reverse for
2 #, 3# pin.
Note: when observe change of resistance value, pay attention to observe whether has large leap.
3. Coolant temperature sensor
(1) This sensor is a negative temperature coefficient (NTC) thermistor, its resistance value decreases with
increase of temperature, but not a linear relationship. This thermistor is installed in a copper heat conducting sleeve.Engine EFI System-Engine EFI System5-121should drop.
Pressure sensor part: (connect joint), turn digital multimeter to DC voltage position, black meter pen is earthed,
red meter pen is connected with 3#, 4# pin respectively. In condition of idle speed, 3# pin should have reference
voltage of 5 V, 4 # pin voltage should be about 1. 3 V (specific value is related with vehicle type); in no-load
condition, open the throttle slowly, change of voltage of 4 # pin is not large; open the throttle quickly, voltage of
4 # pin may reach about 4V in no time (specific value is related with vehicle type), then it drops down to about
1. 5 V.
2. Throttle position sensor
(1) This sensor is actually corner potentiometer with linear output characteristic. Potentiometer tumbler is
mounted coaxially with throttle, when throttle rotates, it drives potentiometer tumbler to slide to certain position,
potentiometer outputs voltage signal proportional to throttle position. Mounting torque: 20 N.m(Max)
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect two meter pens with sensor pins respectively,rated resistance at 20°C is 2.5 k ohm± 5%. Simulation method may also be used for measurement, specificprocedure is to put sensor work area into boiled water (pay attention to soak for sufficient time), observe changeof sensor resistance, now resistance should drop down to 300 ohm-400 ohm (specific value subjects to temperatureof boiled water).
Resistance value (K ohm)
No.Temperature
(°C) Temperature tolerance ±1°C Temperature tolerance ±0°C
Min. Max. Min. Max.
1 8.16 10.74 8.62 10.28 -10
2 2.27 2.73 2.37 2063 +20
3 0.290 0.354 0.299 0.345 +80

4. Knocking sensor
(1) Knocking sensor is a vibration acceleration sensor. Mounted on engine cylinder body. Sensing element of
the sensor is a piezocrystal. Vibration of engine cylinder body is transferred to piezocrystal via mass block in the
sensor. Since pressure generated by vibration of mass block is applied to piezocrystal, it generates voltage on two
polar planes and turns vibration signal into voltage signal for output.5-122Symptom
Poor accelerationPossible cause
Various liquids, such as engine oil, cooling fluid, brake fluid, water etc
contact the sensor for a long time, which cause corrosion to the sensor. Mounting torque: 20 ± 5 N.M
Repair precautions: sensor must be fitted closely to cylinder body with its metal surface, any type of washer
is not permitted for installation. For wiring of sensor signal cables, note that do not let resonance occur to signal
cables, otherwise they might be broken. Energizing of high voltage between sensor 1 # and 2 # pins must be
avoided, otherwise piezoelectric element might be damaged.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect two meter pens with sensor 1 #, 2 # pin
respectively, its resistance value at room temperature should exceed 1M ohm. Turn digital multimeter to millivolt
position, use a hand hammer to tap near knocking sensor, now voltage signal output should be available.
5. Oxygen sensor
(1) Its sensing element is a ceramic tube, outside is open to exhaust, inside is open to atmosphere. When
temperature of sensing ceramic tube reaches 350°C, it will have the characteristic of solid state electrolyte. Just
utilizing this characteristic, it converts concentration difference of oxygen into electric potential difference, thus
forms electrical signal output. If mixed gas is a bit concentrated, inside and outside oxyanion concentration
difference of ceramic tube is high, electric potential difference is a bit high.
A large number of oxyanions move from inside to outside, output voltage is high (approximate 900mV); if
mixed gas is a bit thin, inside and outside oxyanion concentration difference of ceramic tube is low, electric
potential difference is low, only a small quantity of oxyanions move from inside to outside, output voltage is low
(approximate 100mV).
Possible cause
1. humid water vapor ingresses inside of sensor, temperature
changes rapidly, probe is broken.
2. oxygen sensor "is poisoned". (Pb, S, Br, Si) Symptom
Poor idle speed, poor speedup, tail gas
overproof, too high oil consumption1 2 3 4Oxygen sensor Mounting torque: 40-60 N.m
Repair precautions: it is prohibited to use cleaning fluid, oily liquid or volatile solid on oxygen sensor during
repair.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect
two meter pens with sensor 1# (white), 2# (white) pin respectively, its
resistance value at room temperature is 1- 6 ohm.
(Connect joint) in idle speed condition, when oxygen sensor
reaches its working temperature of 350°C, turn digital multimeter to
DC voltage position, connect two meter pens with sensor 3# (grey),Engine EFI System-Engine EFI System

Symptom Possible cause
Fail to start Man made faultSpeed sensor1 2 3Fault symptom Common cause
Dischrge overproof, increased oil consumption Man made fault5-1234#(black) pin respectively, now voltage should fluctuate quickly between 0. 1-0. 9V.
6. Speed sensor
(1) Use with oscillator. Oscillator is a fluted disc, originally has 60 teeth, but two teeth are absent. Oscillator
is mounted on crankshaft, and rotates with the crankshaft. When tooth tip passes by sensor end closely, the
oscillator which is made of ferromagnetic material cuts magnetic line of permanent magnet in the sensor, and
generates induced voltage in coil, which is output as rotating speed signal. Mounting torque: 8 ± 2 N.m
Repair precautions: use pressing in instead of hammering method for installation during repair.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect
two meter pens with sensor 2#, 3# pins respectively, rated resistance
at 20°C is 770-950 ohm.
(Connect joint) turn digital multimeter to AC voltage position,
connect two meter pens with sensor 2 #, 3# pins respectively, start up
engine, now voltage output should be available.
Suggestion: use oscillograph for vehicle use to check.
7. Phase sensor
(1) This sensor consists of a hall sensor and a rotor made of steel plate. Fix hall sensor, mount rotor on camshaft.
Rotor is a 180( range cylindrical face steel blade. When the blade covers hall sensor, high Level signal is output;
otherwise low level signal is output. This differentiates two different upper dead points. Repair precautions: avoid removing end cover as far as possible during repair, so as to avoid ingress of foreign
matter, which might result in abnormal damage of magnetic gate.
(2) Simple measuring method:
(Connect joint) turn on ignition switch but not start up engine, turn digital multimeter to DC voltage position,
connect two meter pens with sensor red, black conductors respectively, ensure reference voltage of 5V is available.
Start up engine, voltage output between green and black conductors should be available.
Suggestion: use oscillograph for vehicle use to check.
8. Idle speed regulator
(1) Idle speed regulator consists of a step motor and a sealing plug on its shaft, sealing plug may generate radial
displacement driven by step motor shaft, position of sealing plug determines extent of opening of by-pass airway,
so as to adjust the size of by-pass air quantity. Position of sealing plug is controlled by ECU output.Fault symptom
Too high idle speed, flameout at idle speedPossible cause
Since interior contamination is severe, regulating element
is blocked and leads to malfunction.
Repair precautions: dust and sand grain will result in damage of idle speed regulator. Intake air should be
filtered by dry air cleaner before entering idle speed regulator, filtration efficiency should exceed 99 %. ToEngine EFI System-Engine EFI System

1 2 3 45-124replacing air cleaner, always ensure that no dirt enters air duct, never
use ungraded air cleaner.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect
two meter pens with regulator pin 1, 4 and 2, 3 respectively. Rated
resistance between 1, 4 and between 2, 3 at 20°C should be about
43.2 ohm.
9. Fuel injector
(1) ECU energizes coil of fuel injector to form magnetic field force. When magnetic field force increases to
sufficient to overcome pressure of return spring, gravity of needle valve and resultant force of frictional force,
needle valve begins to rise, oil injection process begins. When oil injection impulse cuts off, pressure of return
spring closes needle valve again.
Symptom
Poor idle speed, poor speedup, failure to start
(difficult to start)Possible cause
Since lack of maintenance, gum builds up in
fuel injector and leads to malfunction
Repair precautions:
1. there are many kinds of fuel injector, their appearance is the same, mountable fuel injector may not be the
exactly suitable one, part number of fuel injector used in repair must be consistent with original fuel injector, wrong
replacement is not permitted;
2. To facilitate installation, it is recommended to apply silicon free clean engine oil on O ring surface at upper
part connecting distributing pipe of fuel oil. Pay attention not to let engine oil contaminate fuel injector inside and
jet orifice;
3. To remove and reinstall fuel injector, O ring must be replaced, here do not damage sealing surface of fuel
injector;
4. if fuel injector has two slots, when mount buckle clamp, pay attention not to clamp in the wrong position,
refer to mounting position of original parts;
5. It is strictly prohibited to remove strainer, clean or replace strainer at discretion; 6. after removal, ensure
cleanness of fuel injector holder, avoid foreign matter ingressing the cylinder.
Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect two meter pens with fuel injector pins
respectively, rated resistance at 20°C is 11-17 ohm.
Suggestion: use special cleaning analyzer to conduct thorough cleaning for the fuel injector per 20000km.
10. Electric fuel pump
(1) Fuel pump is a vane pump driven by DC motor, is placed in oil tank, immersed in fuel oil, utilizes fuel oil
for heat dissipation and lubrication. Storage battery supplies power to electric fuel pump via oil pump relay, the
relay switches on electric fuel pump circuit only at the time of startup and during operation of engine. When engine
shuts down due to accident, fuel pump stops running automatically.Symptom
Large running noise, poor speedup, failure to start
(difficult to start)Common cause
1. Gum builds up to form insulating layer;
2. Oil pump bushing is blocked with armature;
3. Fuel level sensor assembly is corroded etc.Engine EFI System-Engine EFI System

Symptom
Poor idle speed, malfunction etc
Symptom
Fail to start5-125 Repair precautions:
1. according to engine requirement, electric fuel pumps with different flows are available, they have the same
appearance, mountable fuel pump may not be exactly suitable, during repair, part number of fuel pump used must
be consistent with original one, wrong replacement is not permitted;
2. in order to prevent fuel pump from damaging, please do not run it in dry state for a long time;
3. in case fuel pump needs to be replaced, please pay attention to clean fuel tank and pipeline and replace fuel
filter.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect two meter pens with fuel pump pins
respectively, measure internal resistance, it should not be zero or infinite (namely not in short circuit, open circuit
condition).
(Connect joint) connect fuel pressure gauge on sucker, start up engine, run the engine at idle speed, now fuel
pressure of engine should be about 260kPa; unplug fuel pressure regulator vacuum tube, now fuel pressure should
be about 300KPa.
11. Canister control valve
(1) Canister in fuel evaporation control system adsorbs oil vapor from oil tank until saturated. Electronic
control unit controls opening of canister control valve, fresh air and saturated fuel vapor in canister form
regeneration stream, which is led into engine intake pipe again. Electronic control unit changes duty ratio of pulsing
signal to canister control valve solenoid according to different operating conditions of engine, thus controls flow
of regeneration stream. In addition, this flow is also influenced by pressure difference at both ends.
Possible cause
Entering of foreign matter into valve inside results in
corrosion or poor leak tightness etc
Repair precautions:
1. To install, airflow direction must meet the specification;
2. when black granules inside valve body result in malfunction of control valve, and control valve needs to be
replaced, please check the condition of canister;
3. avoid water, oil etc liquids from entering valve as far as possible during repair;
4. in order to avoid transfer of solid-borne noise, it is recommended to install canister control valve suspending
on the hose or use soft rubber to fix.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect two meter pens with canister control valve pins
respectively, rated resistance at 20°C is 22 - 30 ohm.
12. Ignition coil
(1) When earthing channel of primary winding is connected, this primary winding is charged. Once ECU cut
off primary winding circuit, charging stops, high voltage is induced in secondary winding at the same time, so spark
plug discharges. Ignition coil ZSK 22 (both ends of 2 secondary windings are connected with a spark plug
respectively, so these two spark plugs ignite simultaneously.
Possible cause
Too heavy current leads to burnout, damaged by external force Repair precautions: it is prohibited to use "short circuit ignition testing method" to test ignition function, soEngine EFI System-
Engine EFI System

Engine ECU5-126as to avoid damaging electronic control unit.
(1) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect two meter pens with primary winding pinsrespectively, rated resistance at 2 0°C is 0. 4-0. 6 ohm for 2X2 type; on secondary winding, 11-15k ohm for 2x2 type.13. Electronic control unit ECU
Possible cause
Electric overload of externally connected
device leads to burnout of components inside
ECU and results in malfunction Symptom
Unsteady idle speed, poor speedup, failure to start, too high
idle, tail gas overproof, difficult to start, malfunction of air
conditioner, malfunction of fuel injector control, flameout
Repair precautions:
1. Don't remove ECU at discretion during repair;
2. ECU may be removed more than 1 minute after removing storage battery head;
3. Store removed ECU properly;
4. It is prohibited to attach any circuit onto connecting wire of ECU.
Simple measuring method:
1. (Connect joint) use engine data K-line to read engine trouble record;
2. (Remove joint) check whether ECU connecting wire is in good condition or not, mainly check whether ECU
power supply grounded circuit is normal or not;
3. Check whether external sensor works normally, whether output signal is credible, whether circuit is in good
condition;
4. Check whether actuator works normally, whether its circuit is in good condition;
5. Finally replace ECU to conduct test.
Judgment principle: "two interchange principle" ---interchange ECU, interchange fault symptom.III. Diagnostic system Description:
When engine ECU detects a trouble, engine trouble warning lamp on instrument will illuminate. In addition,
relevant diagnostic code will be recorded in ECU memory. Connect handheld tester with diagnostic interface on
automobile, read various data from automobile ECU. Connect handheld tester with diagnostic interface. Technical
personnel may also read fault code via blinking of instrument fault warning lamp.Engine EFI System-
Engine EFI System

Flashing way of malfuntion code 17 for O2 sensor (3) Each fault code will blink for three times, interval time is 3s, after blinking for the third times, after an
interval of 3s, next fault code will blink. After blinking of all fault codes is finished, they will blink from begining
again. The following diagram shows engine fault warning lamp blinking mode for oxygen sensor fault code 17.5-127Terminal No. Terminal definition
4 Power supply (-)
7 Bus (signal)
16 Power supply (+)Diagnosis connector Notes: use tester cable to connect handheld tester with diagnostic interface, turn ignition switch to ON position,
operate tester, if tester displays that communication is not possible, the vehicle or tester fails.
Inspection diagnosis
1. Check engine fault warning lamp
(1) When ignition switch is turned to ON position and engine does not run, engine warning lamp on
instrument should illuminate.
(2) When engine runs, engine fault warning lamp should go out. If it still illuminates, diagnostic system
detects system fault or abnormity.
2. Use handheld tester to check diagnostic code
(1) Connect handheld tester according to corresponding pin.
(2) Turn ignition switch to ON position, turn on main switch of handheld tester.
(3) Use handheld tester to detect and check diagnostic code, refer to fault diagnostic code table. (For
operation of handheld tester, see instruction manual of handheld tester)
3. Engine fault warning lamp displays fault code through blinking code, so professional may make fault
judgment in case of emergency.
(1)Turn ignition switch to ON position.
(2) Short signal pin (9#) and negative pole (4#) for more than 2. 5s,then disconnect them,detection fault lamp
on dashboard will blink the faults in fault code according to their occurrence sequence.See from terminal outlet
endConnect in jump way over 2.5s and
disconnect
Diagnosis connectorDiagnosis connectorEngine EFI System-
Engine EFI System