Chery SQR 7160 sedan. Manual — part 42
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If stepper motor needs to be replaced, remove the positive connector first and replace actuator. Then
turn ignition key to position 1(accessory position), ECU will readjust actuator position(to limit switch) and
adjust for steps according to engine water temperature so as to adjust idle speed with valve linear (axial
direction)movements(forward or backward).
Only CHECK-UP1 tester may be applied to check whether it’s running properly.
3.1MARWAL low pressure fuel pump“MSS070”
The fuel pump in this system is atmospheric
positive shift (see figure. 142). It is designed to work
with ethyl as its standard fuel and equipped with a
check valve and a pressure override valve (vibration
pressure is 2.6bar). It is installed inside the fuel tank and
equipped with a fuel filter.
Fuel pump supplies the fuel to fuel injectors and is
controlled directly by ECUD to ensure:
·The fuel pump will close when engine speed drops
under the minimum starting speed or engine stops.
· The fuel pump signal is timed. once ignition
switch is on and engine is not started , there will be a
fuel pump signal within 10 seconds.
· Under the engine running and starting conditions,
the fuel pump signal will not change.
Fig. 142 fuel pump
Fig. 141 Idle step motor and air by-pass valve
valve
idle actuator
by-pass channel
throttle
valve
throttle
valve
leak
by-pass
air control.
feature
parameter
electric connector
outlet
operation temperature
spiral resistance
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3.2 fuel filter
Fuel filter (see drawing 143) is connected between fuel pump and
the fuel intake port of the throttle valve body. It comprises an aluminum
case and a bracket with a stainless steel in it. for the high sensitivity of
fuel injector and the the existence of external impurities being in the fuel
system, it is necessary to use the high-efficiency paper filter core.
4.1water temperature sensor“WTS05”
during cold starting and engine warming, ECU enrich the mixture according to the signal (see figure 6)
from the sensor. When engine is warmed enough for fan to reach the operation range, the enrichment is zero.
4.2 speed, top dead center and
s
ynchro pickup“CVM01”see figure. 144
Sensor is mounted on the cylinder block by a mounting bracket. When it detects the impulses produced by
the teeth (60—2) in the flywheel (see figure. 143), engine speed may be calculated accurately by the signal
impulses produced by the 58 teeth which are arranged equally with a interval of 6°.
The RPM sensor position in the flywheel (signal wheel) is on the surface of the twentieth tooth before the
top dead center of the cylinder 1, 4, the angle between it and the top dead center of cylinder 2, 3 is 80°, on the
opposite of the fiftieth teeth (tooth counting begins from the tooth-missed area), except for deciding cylinder
1,4 and cylinder 2,3 TDC, the sensor signal (see figure. 144) is also used in the microprocessor：
—— Control ignition ( ignition advance and ignition delay)
—— generate signal for the RPM counter
—— detect two missed teeth to confirm the synchronous position every engine revolution
Without the signal or the corresponding synchronous signal (60—2 signals/revolution)，ECU cannot be
operated.
Fig. 143 fuel filter
sensor characteristic
winding
positive signal
negative signal
grounding singal
Fig. 144 tacho sensor
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timing：
Rotate the engine pulley(2) to keep cylinder 1 and cylinder 4 at TDC, i.e. the mark on the pulley (2) and
the mark (3 and 4) on the timing wheel cover of engine must be matched (see figure. 145).
speed/ TDC sensor
Check if the sensor is located in the twentieth tooth after the breach in the flywheel signal panel
1— speed/ TDC sensor( crankshaft position sensor)
2— pulley
3— TDC reference point on the pulley
4— TDC reference point on the timing gear cover
5— synchronous tooth
Check the air gap between the sensor and flywheel：
Magnetic thickness gauge is used for checking the air gap between the sensor and flywheel. Measurement
should be made at least at three different teeth with a equal interval of 120°. The value should be 2±0.6mm.
A. speed sensor signal
B.ECU power signal
C. current circle for primary coil circuit
a. ignition advance angle relative to cylinder 1
TDC
4.3 absolute pressure sensor
The sensing element of absolute pressure sensor is printed
in a ceramic membrane by the wheatstone bridge silk PCB.
One side of the membrane is absolute reference vacuum and
the other side is actual vacuum of the intake manifold. The
signal (piezoresistance type) produced by the distortion of
ceramic membrane which is installed in the bracket is
magnified by the circuit located in the carrier before being
transferred to ECU.
see from the front end, rotation direction
top dead center position
crankshaft
position sensor
Fig. 145 sensor position and timing
reference point
Fig. 146 magnetic sensor output signal wave
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3-way connector ( figure. 147)
a. supply 5V voltage
b. negative pole signal
c. positive pole signal
When engine is shut down, the sensitive membrane will bent
according to the value of atmospheric pressure (mmHg). After the
ignition switch is switched on, the actual atmospheric pressure may be obtained by this method.
When engine is running, the vacuum will produce a mechanical effect on the ceramic membrane of the
sensor resulting in the change of resistance.
for ECU supplies a absolutely constant 5V voltage , the
change of output voltage caused by the change of resistance is
indicated in figure. 148.
Sensor supplies the most important data to ECU for
calculating the intake air volume. When the pressure signal is P
＜97mmHg or P＞783mm Hg，if the throttle valve position
sensor doesn’t fail, the operation comeback will be performed
according to the throttle valve angle and speed value stored in the
calibration scale. If throttle valve fails, only one comeback
value may be applied—— about 442mmHg.
Note: If absolute pressure sensor needed to be
replaced, the connecting pipe must have the same
diameter and length as the original pipe.
5 ignition advance calculation and high voltage distribution
The system uses two high tension ignition coils and assigns ignition voltages directly to spark plugs by
static electricity (distributorless ignition) directly. Connector and controlling triode are comprised in the ECU
injection system and connected to ECU connector 1 and connector 19 . (figure. 149).
Fig. 147 absolute pressure sensor
Fig.148 sensor output
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