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Chery A11. Manual - part 156

Maintenance Manual for Chery·Windcloud

Marelli EFI System

11. Carbon Canister Control Valve

Purpose: to be used for the control of purge

flow rate of carbon canister. Carbon canister

control valve is controlled by ECU in

accordance with engine load via the duration

and frequency of electric impulse (i.e. duty

ratio). Excessive accumulation of gasoline

vapor in charcoal canister will lead to

gasoline leakage and pollution, therefore,

the function of carbon canister

electromagnetic valve is to open the said

valve as appropriate so as to transfer

excessive gasoline vapor into air intake pipe

for combustion, in addition, the aforesaid

valve shall be opened at small and medium

load of engine, while closed at idle speed

and heavy load.

Composition and principle: carbon

canister control valve consists of solenoid,

armature and valve, etc. There is a filter

screen on inlet. And the airflow rate passing

through carbon canister control valve is

related to duty ratio of electric impulse

outputted by ECU to the said valve on one

hand, while related to pressure difference

between its inlet/outlet on the other hand. In

case there is no electric impulse, carbon

canister control valve will shut down. ECU

controls the said valve’s current-on time and

indirectly controls the rate of purge flow

according to signals provided by sensors of

engine.

Failure diagnosis: ECU functions failure

diagnosis on driver stage of carbon canister

control valve instead of the said valve. In

case short circuit, overload, short circuit to

ground or open circuit occurs on driver stage

of carbon canister control valve to

accumulator voltage, fuel rated closed-loop

control basic self-learning and idle speed air

requirement self-learning are shut down, and

the self-learning data are valid. If failure

occurs on the aforesaid valve, generally

engine shows instable idle speed or

excessive idle speed.

Carbon canister control valve

Main relay

Carbon canister electromagnetic valve

Circuit diagram of carbon canister control valve
TEV-2

Pins:

Pin 1 connecting with Pin 87 of output

terminal of main relay;

Pin 2 connecting with Pin 52 of ECU.

Troubleshooting: blockage or crack of
carbon canister causes the increase of air
intake.

Maintenance Manual for Chery·Windcloud

Marelli EFI System

12. Assembly of Steely Fuel Distributing
Pipe

Purpose: to store and distribute fuel to
provide fuel injection system with a fairly
stable pressure environment, to achieve
counterbalance of supply pressure and fuel
feed of each cylinder as well as smooth
engine operation.

Composition: fuel distributing pipe
assembly is made up by fuel distributing
pipe and injector.

Installation requirement: connect fuel
inlet/outlet pipes with rubber pipes and
fasten them down with hoops. The size of
hoops used shall match that of rubber pipes
so as to ensure air-tight connection between
fuel inlet/outlet pipes and rubber pipes.

Failure diagnosis: generally, the probability
for failure occurrence of fuel feeding header
pipe is slim. Mostly, failure is caused by
improper assembling, which leads to leakage
in fuel system, therefore, be careful when
assembling: O-ring oil seal used can not be
reused; when assembling, apply some
lubrication oil as appropriate.

Fuel distributing pipe assembly

Maintenance Manual for Chery·Windcloud

Marelli EFI System

13. Rotational Speed Sensor
Purpose: rotational speed sensor provides

engine ECU with rotating speed, rotating

angle and reference signals for control of

engine cylinder detection and ignition;

rotational speed sensor of induction type

combines with oscillator to provide engine

speed information and crankshaft top dead

center information in the distributor-less

ignition. Rotational speed sensor of

induction type is made up of a permanent

magnet and coils wound on magnet.

Oscillator is a fluted disc with 60 teeth

originally, except for 2 vacant teeth. It is

installed on crankshaft and rotates with it.

When tooth point passes from next to the

end of rotational speed sensor of induction

type, oscillator made from ferromagnetic

material cuts magnetic force lines of

permanent magnet of the aforesaid sensor,

generating induced voltage and outputting as

rotating speed signal.
Composition and principle: This vehicle

adopts rotational speed sensor of magnetic

pulse type, with coils winding around a slug

inside, signal wheel rotating at high speed

and cutting magnetic lines of force; induced

electromotive force is generated in coils,

while ECU, according to the frequency of

the said force generated, calculates engine

rotating speed for the use of engine control.

Installation requirement: clearance 20.5
mm (nonadjustable)

Coil resistance: 1150-1400 ohm

Failure diagnosis: engine ECU will identify

failure of crankshaft position sensor in case

that any of the following conditions occurs

in sensor:

Sensor line short circuit to ground;

Sensor line open circuit;

Sensor signal distortion.

After failure of rotational speed sensor is

identified, engine will not be started, and

fuel pump relay will not be ON.

Troubleshooting: check to see if sensor line

is normal;

Check to see if resistance in sensor is

normal;

Check if shielded line circuit is open.

Assembling schematic drawing for

crankshaft position sensor

Engine rotational speed sensor

Circuit diagram of rotational speed sensor
Pins: Pin 1 connecting with ECU’s 53# pin
(signal +)

Pin 2 connecting with ECU’s 67# pin

(signal -)

Pin 3 connecting with ECU’s 77# pin

(shielded line)

Maintenance Manual for Chery·Windcloud

Marelli EFI System

Chapter Two: Basic Principle for EFI System Failure Diagnosis

(1). Failure Information Record
Electronic control unit constantly monitors sensors, actuators, relevant circuits, fault
indicating lamp and accumulator voltage, etc. and even electronic control unit itself, and
carries out reliability test on sensor output signal, actuator drive signal and internal signal (for
instance: oxygen closed-loop control, knocking control, idle speed control and accumulator
voltage control). Once a certain link is found failed, or a certain signal value is unreliable,
electronic control unit will make information record of failure immediately in failure
memorizer of RAM. Failure information record will be stored in form of failure code, and
displayed as per sequence of failure occurrence.
Failure, according to frequency of occurrence, can be divided into “constant failure” and
“random failure” (for example: failure caused by temporary wire harness open circuit or
poor contact of socket connector).

(2). Failure Status
If the continuance of an identified failure exceeds the stabilization time stipulated for the first
time, ECU collects it as a stable failure, and stores it as “constant failure”; if such failure
disappears, ECU stores it as “random failure” and “nonexistent”; if such failure is identified
again, then still it is “random failure”, but the “existent” history failure does not impact the
normal use of engine.

(3). Failure Types
Short circuit to power supply anode
Short circuit to on ground
Open circuit (on occasion that input stage has upward pull/downward pull resistor, ECU will
identify the open circuit failure at input port as input port failure of short circuit to power
supply anode or short circuit to ground)
Signal unreliable

(4). Four Types of Failure
Max. failure, signal exceeds upper limit of normal range.
Min. failure, signal exceeds lower limit of normal range.
Signal failure, no signal.
Illogical failure, signal exists, but illogical.

(5). Limp Home
For some important failures identified, whose duration exceeds stabilization time stipulated,
ECU will adopt software countermeasure as appropriate, for example: shutting down some
control functions of oxygen sensor closed-loop control and setting substitute value for
unreliable data considered. Although engine has relatively poor working condition, the car
can still run. The aim of this is to let the car get home after a fashion or have examine and

Content .. 154 155 156 157 ..