Chery A11. Manual — part 173

Maintenance Manual for Chery·Windcloud

MOTOROLA EFI System

Users are not allowed to adjust throttle valve adjusting screw on throttle body. The position of

such screw has been accurately adjusted in final assembly. Improper adjustment may cause

high idling speed, engine closing down or affect idle speed stability, emission and economical

efficiency of fuel consumption.

4.9 Engine error indicating lamp

Error indicating lamp locates in the front instrument panel. In case serious error occurs, the
lamp will flash, which requires professional mainantenance staff to use corresponding tools to
check vehicle and effect troubleshooting in a timely manner.

4.10 Other precautions

Constant failure of EFI system is caused mostly by defect connection, so the node of each
connector lug shall be clean and safely connected/contacted; electronic control unit is a
component of high quality with little failure, special equipment shall be adopted when
examination is necessary, and random overhauling is not allowed. When ignition switch is
ON, do not proceed with operation of disconnecting any electrical equipment so as to avoid
damage on electronic component caused by induced electromotive force (which is generated
in circuit).

Failure Diagnosis for EFI System:
Generally, the failure of EFI system is caused by the following reasons:
(1) Engine EFI matching problem, generally such problem may occur in the preliminary

stage of vehicle’s coming into the market. For example: unsteady idle speed, flameout,
etc.; and on the other hand, these problems occurein lots, which are undissolvable
basically through maintenance, therefore, if such problems occur, feel free to contact
After-sale Service Dept.

(2) In EFI system, the most frequent problem is caused by defect connection. After

replacing a certain part, many problems are solved and failure is eliminated; however,
when fixing the old part into aother vehicle, the said vehcile can be used normally.
Therefore, it is advisable that the relevant components in EFI system shall be checked
first to see if their connections are in good order when such problems occur.

(3) The EFI system parameter and data flow in the process of maintenance are very

important, therefore, it is advisable not to judge problem simply by failure code during
maintenance, but to judge/settle problem by data flow in combination.

22

Maintenance Manual for Chery·Windcloud

M7.9.7 EFI System

Chapter One: Operating Principle for
EFI Control and Execute Components

1. Intake Pressure and Intake Air
Temperature Sensor
Purpose: detects manifold absolute pressure
from

0.1~0.2bar

and intake air temperature,

provides engine with load information.
Composition and principle: this sensor is
composed of two different sensors (i.e.
manifold absolute pressure sensor and intake
temperature sensor), and is installed above
pressurizer.

Pressure-sensitive element inside intake
pressure sensor detects pressure signal on
intake manifold for injection pulse width
control of EFI system. This sensor also
serves as the substitute of load signal sensor.
Intake air temperature sensing element is
a resistor of negative temperature coefficient
(NTC), which is similar to water
temperature sensor with resistance value
decreasing with the increasing of intake air
temperature. And engine ECU monitors the
variation of intake air temperature via a
comparison circuit inside.

Failure diagnosis: The electronic device
next to intake pressure sensor detects sensor
circuit troubles such as open circuit, short
circuit and sensor damages, etc. In case
ECU detects any sensor output signal that
goes beyond output characteristic curve, the
sensor is diagnosed as failed by ECU. For
example: when intake pressure is higher
than upper limit or lower than lower limit,
ECU detects sensor failure (in case that
intake pressure is lower than lower limit
when starting, ECU is able to recognize the
starting condition), and the engine fault
indicating lamp goes on. Under this
condition the engine works in failure mode.
Installation: to be installed on pressurizer.
Troubleshooting: mainly check if there is
short circuit or open circuit on the
connection between 4 lines on senosr and
ECU.
If there is short circuit, open circuit or

grounding between sensor wire harnesses.

Manifold absolute pressure /intake air temperature sensor

Manifold absolute

pressure and intake air

temperature sensor

Circuit diagram of manifold absolute pressure and intake
air temperature sensor

Pins: 1# is grounded (connecting ECU 17#);

2# outputs temperature signal

(connecting ECU 40#);

3# connects with standard 5V power

source (connecting ECU 33#);

4# outputs pressure signal (connecting

ECU 37#).

Sectional view of intake pressure and intake air
temperature sensor

1 Seal ring

5 Casing

2 Stainless steel bushing

6 Pressure bracket

3 PCB

7 Welded joint

4 Sensing element

8 Bonded joint

1

Maintenance Manual for Chery·Windcloud

M7.9.7 EFI System

2. Throttle Position Sensor

Purpose: this sensor is designed to provide
ECU with information of throttle angle. As
per such information, ECU obtains engine
load information and operating mode
information (for instance: start-up, idle
speed, reverse, part load and full load) as
well as acceleration and deceleration
information. This sensor is three-wire style,
and the throttle opening can be detected by
ECU via monitoring voltage variation.
Composition and principle: Consisting of
two compass sliding contact resistors and
two sliding contact arms, throttle position
sensor is an angle sensor that outputs linear
signals. The axes of contact arms are on the
same axial line with throttle axis, with 5V
power supply voltage U

S

being applied to

both ends of each contact resistor. When
throttle turns, contact arms turn along with it
and move on sliding contact resisters,
educing potential of contacts U

P

as output

voltage. This sensor is actually an angle
potentiometer.


Failure diagnosis: ECU monitors throttle
angle, and detects sensor failure when
output signal exceeds upper or lower limit,
in which case engine will work in failure
mode, and fault indicating lamp will go on.




Installation: allowable tightening torque
for fastening screw is 1.5Nm-2.5Nm.

Throttle position sensor

Circuit diagram of throttle position sensor

Pins:
1 sensor signal ground (ECU17#)
2 5V power (ECU32#)
3 sensor signal (ECU16#)

Troubleshooting: mainly check if there is

short circuit or open circuit on the

connection between 3 lines on senosr and

ECU.
Check to see if there is short circuit, open
circuit or grounding between sensor wire
harnesses.

2

Maintenance Manual for Chery·Windcloud

M7.9.7 EFI System

3. Coolant Temperature Sensor TF-W

Purpose: this sensor is designed to provide
coolant temperature information. To provide
engine ECU with water temperature signal
used for control of ignition timing and fuel
injection pulse width in startup, idle speed
and normal operation.

Composition and principle: this sensor is a
thermistor of negative temperature
coefficient (NTC) with resistance value
decreasing with the increasing of coolant
temperature except linear relation. The said
thermistor is installed in a heat-conducting
sleeve. ECU monitors water temperature
variation by converting resistance value of
thermistor into a changing votage through a
bleeder circuit (inner structure of ECU).



Failure diagnosis: When coolant
temperature is higher than allowed upper
limit or lower than lower limit, failure mark
of the knock sensor is set, engine fault
indicating lamp goes on and engine works in
failure mode. In this case ECU controls
ignition and fuel injection according to set
water temperature for failure mode, at the
same time the fan is running at high-speed
mode.


Limiting data: 2.5±5%KΩ
Installation hint: tightening torque is 15Nm
in maximum.
Hints: the vehicle is equipped with 2 water
temperature sensors, one is single-pin water
temperature sensor, providing the water
temperature gauge with water temperature
signal; the other is double-pin, providing the
engine ECU with water temperature signal.

Coolant temperature sensor

Coolant

temperature

sensor

Circuit diagram of coolant temperature sensor

Pins: this sensor has 3 pins, which can

interchange for use.

1 coolant temperature sensor signal (ECU

39#)
2 sensor signal ground (ECU 35#)
3 another line connects water temperature
signal of gauge.

Troubleshooting: mainly check if there is

short circuit or open circuit on the

connection between 3 lines, ECU and

gauge on senosr.

If there is short circuit, open circuit or

grounding between sensor wire harnesses.
Line grounding or defect grounding is liable
to cause engine water temperature gauge to
indicate excessive temperature.

3