Chery SQR 7160 sedan. Manual — part 118
●Measuring Method
a ohmmeter method
Measure resistance with an ohmmeter, and determine if water temperature sensor operates
upon measured engine coolant temperature and below diagram. Remove coolant
temperature sensor, immerse into water and heat water. The sensor has different resistance
at corresponding temperature.
Water Temperature Sensor Resistance Specification
Temperature(℃)
Resistance(Ω)
Temp.(℃)
Resistance(Ω) Temp.(℃)
Resistance(
-40 100865
25
2795
90
241.8
-35 72437
30
2240
95
207.1
-30 52594
35
1806
100
178.0
-25 38583
40
1465
105
153.6
-20 28582
45
1195
110
133.1
-15 21317
50
980
115
115.7
-10 16120
55
809
120
100.9
-5 12261
60
671
125
88.3
0 9399
65
559
130
77.5
5 7263
70
469
135
68.3
10 5658
75
395
140
60.3
15 4441
80
334
145
53.4
20 3511
85
283
150
47.5
b voltmeter method
Install the sensor on the motor, and crank engine. Connect sensor signal lead to
voltmeter, there are different voltage drop at different temperature.
Oxygen sensor
Oxygen sensor is installed on exhaust pipe and accurately regulate excess air co-efficiency .
Oxygen sensor has 4 leads: C. voltage lead (pin A16) B. signal lead (pin B1)
A. signal ground (pin B23) D heater ground (pin B16)
PIN Function
C Sensor
voltage lead
B Sensor
signal
output
A Signal
ground
D Heater
ground
Oxygen sensor heater resistance impedance specification table
when temperature is 23℃, impedance is
13.2+/-10%
Resistance Heat Co-efficiency of
impedance
(23-800℃) (ppm/℃)
1150
When temperature is 800℃, impedance
is
25.0+/-10%
When temperature is -40℃, heater
impedance is
12.2+/-10%
●Detecting Method:
a、voltage signal method
Before testing oxygen sensor, engine must be under normal operation temperature.
【Note】Only digital voltmeter can be used to test oxygen sensor, otherwise oxygen sensor
will be damaged.
● During testing, the insulation may be pricked. Before testing, digital voltmeter leads
must be connected to oxygen sensor ground lead and signal lead. When engine idles and
under normal temperature, if air/fuel ratio has some difference with ideal air/fuel ratio, the
oxygen sensor output voltage will vary from low to high periodically. The voltage
periodically varies from 0.3V to 0.8V. After testing, apply silicon seal gum on pricked
area.
●
A continuously high voltmeter reading indicates an rich air/fuel ratio polluted oxygen
sensor ambient temperature silicon seal gum or antifreeze agent polluted oxygen sensor or
leaded fuel used in engine.
A continuously low voltmeter reading indicates an poor air/fuel ratio, sensor fault. A
medium reading maintained indicates a possible oxygen sensor fault.
● Remove oxygen sensor from engine. Connect a digital voltmeter lead to sensor, and
combust sensor sensitive element on propane welding torch flame. The propane flame could
isolate the sensitive element from oxygen, which will generate voltage. When sensitive
element is on flame, the voltage is approximately 1V, and when moved away the flame, the
voltage will drop to 0V. If sensor voltage does not change as specified, replace the oxygen
sensor.
◆Heating wire diagnostic
If the heater on sensor does not work, sensor pre-heating will be delayed, and computer
work time will also be prolonged. Then computer send a wrong rich air/fuel ratio signal,
wasting the fuel.
b、Ohmmeter method
Remove oxygen sensor and connect the ohmmeter between the heating wire and ground
wire. Referring to above diagram, if the resistance measured is not as specified, replace it
2.1.5 Speed sensor
◆ If speed sensor is damaged, the engine can not be started.
Speed sensor has 2 leads, one is signal lead (pin B7) and the other is ground wire (pin B6)
⑴ speed sensor
⑵ belt pulley with teetht
⑶ signal output
⑷ signal corresponding to 2
mis-teeth.
Speed sensor determines firing and fuel injection time by monitoring the teeth on the flying
wheel, engine speed and crankshaft position signal.
● Testing method
a ohmmeter method: the coil resistance is 515Ω,
b oscilloscope
method:
Use oscilloscope to monitor pulse waveform, and a voltage pulse will generate when a
tooth pass by. The flying wheel on this engine have 60-2 teeth.
2.1.6 Ignition
coil
Ignition Coil Electrical Specification
Primary coil induction
5.80±15%mH
Primary coil resistance
0.53±10%Ω
Secondary coil induction
12.8±10%kΩ
Secondary coil resistance
40.0±20%H
Testing voltage
2Vdc
Testing current
7.0Amps
Output (no load)
40kvMin
Output (50Pf load)
40.0±7%mJ
Energy storage time (reference)
6.3ms
Secondary peak value current
74mA±7%
I firing delayed time
3.6ms±3%
Coil number ratio
83:1
● Testing method
Ohmmeter method: referring to above chart and check ignition coil resistance.
● Ignition wire
Remove ignition wire and 5-8mm away from cylinder. Turn on ignition switch, start engine
and watch flame. A strong blue flame indicates a operational ignition coil. Otherwise, check
ignition coil. Using ohmmeter method, referring to above chart, check and remove injector
connector before checking.
● Monitoring each cylinder misfire
Remove each cylinder spark plug, and connect to appropriate high-tense wire, ensuring
spark plug thread reliably ground on cylinder body. Start engine and monitor spark plug
misfire.
2.1.7 Throttle position sensor (TPS)
TPS fault may cause unsmooth acceleration, engine stalling and rough idle etc. TPS has 3
leads, a current lead (Pin B22), a ground lead (Pin B23) and a signal lead (B17).
● Testing method
a ohmmeter
method:
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