Chery A11. Manual — part 155

Maintenance Manual for Chery·Windcloud

Marelli EFI System

7. Electric Fuel Pump

Purpose: to carry fuel from fuel tank to

engine fuel injection system at a certain

pressure and flow rate (different in systems).

Composition and principle: electric fuel
pump is coaxially installed with pump motor
in the same casing. It is constituted by direct
current motor, vane pump and end cover
(integrating check valve, decompression
valve and anti-electromagnetism
interference component). Pump and motor in
the casing are surrounded by fuel, through
which they reject heat and get lubricated.
Accumulator supplies power to electric fuel
pump through fuel pump relay, which closes
pump circuit only when the engine is
starting or running. In case engine stops due
to failure, fuel pump stops automatically.
The maximum pressure of electric fuel
pump outlet is determined by decompression
valve between 450-650kPa, while the
pressure of entire fuel system is

350kPa in

general.

Flow rate of fuel pump is 76L/H.

Caution: Fuel temperature has fairly big
impact on fuel pump performance, in case of
longstanding operation under high
temperature condition, when fuel
temperature is higher than a certain value,
the pressure of fuel pump drops dramatically,
in this case, if engine fails to start when
warming-up vehicle, please check carefully
whether the high temperature performance
of fuel pump is out of condition.

Working temperature: -30 - +70°C

Electric fuel pump

Main power

Power relay

Fuel pump control

Circuit diagram of electric fuel pump

Fuel pump relay is controlled by ECU
15#pin.
Pins: electric fuel pump has 2 pins, which

connecting with fuel pump relay. “+” and

“-” are marked on the fuel pump housing

beside both of the 2 pins, which indicates

connecting with anode and cathode

respectively.
ECU 70# pin controls fuel pump relay.

Troubleshooting: generally the failure of

fuel pump appears as insufficient fuel

pressure or no pumping-out of fuel. In case

of troubleshooting, system fuel pressure

shall be checked to see if it is within the

scope of specified value and if pipeline is

leaking.
In addition，fuel tank’s positive pressure and
negative pressure will have impact on fuel
system and further on EFI performance.

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Maintenance Manual for Chery·Windcloud

Marelli EFI System

8. Electromagnetic Injector

Purpose: according to ECU instruction,
injector ejects fuel within the stipulated time,
by which means providing engine with fuel
and atomizing it.
Composition and principle: ECU sends out
electric impulse to injector coil, forming
magnetic field force. When the magnetic
field force increases well enough to
overcome resultant force of retracing spring
pressure, pin valve gravity and friction, pin
valve starts to lift, and the fuel injection
begins. The maximum lift range of pin valve
shall not exceed 0.1mm. In case fuel
injection impulse is cut-off, the pressure of
retracing spring enables pin valve to switch
off again.

Installation hints: a certain injector shall
apply to a certain pin without mixing use.
In order to facilitate installation, it is
recommended to apply uncontaminated
silicon-free engine oil to the surface of
upper O-ring connecting with fuel
distributing pipe. Be careful not to let engine
oil contaminate interior or squirt hole of
injector.
 Install injector into injector seat in the
direction perpendicular to the seat, and then
fix the injector on it with clamp. No
discontinuous resistance shall be felt when
rotating injector manually.

Caution: for long-term idle vehicle,
gasoline cementation in injector results in
failure of normal startup of vehicle after
long-term idling. In this case please check
carefully to see if the injector cements, and
check atomization as well

Failure diagnosis: EFI system of A11 does
not apply failure diagnosis to injector itself,
but to injector driver stage. When the driver
stage of injector is in short circuit or excess
load status to accumulator, in short circuit
and open circuit status to ground, the failure
mark is set. At this point, shut down oxygen
sensor closed-loop control and its
self-learning precontrol, the last
self-learning data is valid. After
troubleshooting, failure mark restores.

Working pressure: 350 kPa
Injector resistance: 13.8 -15.2± 10%
Working temperature: -30°C - +110°C

Electromagnetic injector

Main power

Circuit diagram of electromagnetic injector

Pins: each injector has 2 pins. Of which, the
one marked with positive sign beside
housing shall be connected with 87# pin of
fuel pump relay output terminal; the other
shall be connected with 71#, 79#, 78# or 72#
pin of ECU respectively. Grounding
(injection pulse width) is controlled by
ECU.

Troubleshooting: generally injection
nozzle’s non-smooth fuel injection and
defect atomization is caused by long-term
application of engine. To solve this
problem, periodical cleaning of injection
nozzle is required.
Short circuit, open circuit in interior coil of
injection nozzle may also result in fuel
injection system failure.
Check to see if there is short circuit or open
circuit in system line (between injectors
and ECU 71, 79, 78, 72 pins).

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Maintenance Manual for Chery·Windcloud

Marelli EFI System

9. Idle Speed Actuator Stepper Motor
DLA

Functions: there is also a bypath air passage
provided by idle speed actuator with stepper
motor. When throttle is shut, air enters
engine through this bypath air passage. ECU
controls the section area of this passage
through a stepper motor to control the intake
volume and fuel injection. When engine is
idling, increasing or decreasing the section
area of bypath air passage may increase or
decrease engine speed and achieve
closed-loop control of idle speed.

Composition and principle: Stepper motor
is a micro electrical machine, which consists
of several steel stators arranged in a circle
and a rotor. Each steel stator is covered by a
coil; rotor is a permanent magnet, center of
which fixed a nut. All stator coils are
electrified all the time. Once the current
direction of a coil is changed, the rotor will
rotate by an angle. When all stator coils are
changing their current directions in a proper
order, a rotating magnetic field is formed to
keep permanent magnet rotor rotating in a
certain direction.
Failure diagnosis: ECU can monitor short
circuit, open circuit status of two coils in
idle speed stepper motor, and lighten engine
failure lamp when such failure occurs, then
engine enters failure mode.
Hints: ECU diagnosing system only
monitors circuit of actuator, and it dose not
detect if the stepper motor actually
implements that command, i.e. it is possible
that ECU sends a command, and stepper
motor circuit has no problem, but stepper
motor is unable to implement the command
due to sticking. This situation may result in
unstable idling and flameout with no failure
code displayed.
Working voltage: 6-16V DC

Coil resistance: (1-4, 2-3) 53ohm at 23 ±5 ℃

Min. stroke ensured by pusher: 8.9 mm

(around 214 steps)

Idle speed actuator stepper motor

Idle speed stepper motor

Circuit diagram of idle speed actuator stepper
motor

Pins:

Pin 1 connects to ECU 64# pin;

Pin 2 connects to ECU 65# pin;

Pin 3 connects to ECU 57# pin;

Pin 4 connects to ECU 58# pin;

Troubleshooting: short circuit or open

circuit occurs to the four wires connecting

stepper motor and ECU;
Check if stepper motor gets stuck;
Check if short circuit or open circuit occurs
to stepper motor.

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Maintenance Manual for Chery·Windcloud

Marelli EFI System

10. Ignition Coil
Function: ignition coil transforms low
voltage of primary winding into high voltage
of secondary winding, spark is generated
through discharge of spark plug to ignite
fuel and air mixture in cylinder.

Composition and principle: ignition coil is
composed by primary winding, secondary
winding, slug and casing, etc. In case
voltage of accumulator is added onto
primary winding, the said winding is
charged; once ECU cuts off circuit of
primary winding, charging stops and at the
same time, high voltage is inducted on
secondary winding. Also, ECU controls
on/off condition of basal pole of ignition
coil amplifier via a wire so as to control
ignition.

Failure diagnosis: ECU can not function
failure diagnosis on ignition coil, so in case
any problem occurs in ignition coil, there is
no failure code, the only way is to check the
resistance of ignition coil to determine if the
said coil is in working order. Under normal
conditions, the thermal value of working
ignition coil is fairly big, however, excessive
temperature will lead to the increase of
resistance value of ignition coil, unsteady
performance and flameout of engine will
occur.

Primary winding resistance (A-B or C-B):
0.4ohm ±10% (23°±5°C)
Secondary winding resistance (Cylinder
1-4 or Cylinder 2-3):
4900ohm ±10% (23°±5°C)

Ignition coil

Main relay

High
voltage coil

Circuit diagram of ignition coil

Pins:

Primary winding of 1# coil connecting with

59# pin of ECU;

Primary winding of 2# coil connecting with

main relay;

Pin 3 connecting with Pin 66 of ECU.
High-voltage side:

Connect 1#, 2#, 3#, 4# pin respectively with

spark plug of corresponding cylinder

through sub live wire.

Troubleshooting: short circuit or open

circuit occurs inside coil;

Coil creepage, housing crack;

Coil aging leads to insufficient electric

quantity of ignition.

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