Chery Fora (Elara A520). Manual — part 146

CHERY·A21 SERVICE MANUAL ENGINE EFI SYSTEM

23

make the heat exchange different of the heat
diaphragm of both sides.

This will make the temperature of two sensing
element measuring point inside of the flowmeter
Changes differently and appears difference in
temperature. And the difference of the temperature
will increase with the increase of the airflow.
Big/small and positive/negative of the temperature
difference improved the quality and direction of the
airflow. And the inside evaluate circuit will transfer
the temperature difference to voltage signal and
output.

5)Working temperature:-40--125℃

6)Malfunction and diagnosis method

l Reason: sensing element is polluted by the dust

particle, oil and water and causes the part invalid.

l Service notice: 1, it is prohibited to use erosion

liquid to clean sensing element during service; 2,
not to use high pressure air to impact sensing
element; 3, make sure there are no dust into air
pipe when you change air cleaner and no
unqualified air into air cleaner.

l Simple measuring method: static measurement:

(zero flow measurement) No. 3 grounding; No. 4
input 5V reference voltage; No.2 input 14V rated
voltage; check No. 5 output voltage, if the output
is bigger than 1.025V, we can confirm the
function of this sensor is not qualified. Dynamic
measurement: if it is confirmed the sensor is
broken, connect a tail gas analysis meter to
exhaust pipe and check it by using “two working
conditions method”: 1, idle speed working
conditions; 2, 2000rpm stable working conditions.
Check the reading of HC 、CO、CO

2

, normally

HC<100ppm CO<0.5%,CO

2

>13.5%

3.10 DOUBLE SPARK IGNITION COIL

1)Exterior and pin definition

No. 1 coil primary winding connect with No.5 pin of
ECU; No. 2 coil primary winding connect with No. 2
pin of ECU; No. 3 and No.4 pins connect with power

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anode.

2)Installation position: on the engine

3)Purpose: Ignition coil transfers the low voltage of
primary winding to high voltage of secondary
winding, and produce spark by spark plug discharging
then burning the combustible gas inside of the
cylinder.

4)Working principle

Ignition coil ZS - K22 is made up of two primary
windings, two secondary windings, mandrel, and
casing. When one of the primary windings grounding
chunnel is connected, the primary winding is in
charging. Once the circuit is cut off by ECU, the
charging is stopped. At the same time the high voltage
is sensed in the secondary winding and making the
spark plug discharging. There is a different with the
distributor ignition coil: for the ignition coil ZS - K22,
there is one spark plug on both side of the secondary
winding, and the both spark plugs can ignite at the
same time. These two primaries connect and
disconnect

to

power

alternatively.

And

correspondently these two secondary windings
discharge alternatively.

5)Working voltage:14V

Working temperature:-40—120℃

6)Malfunction and diagnosis method

l Malfunction: can not start.

l Reason: current is too big and got burnt, damaged

by outside force etc..

l Service notice: forbid to use "short circuit test

igniting method” to test ignition function,
prevents the electronic controller from damaging.

l Simple measuring method: (disassemble the joint)

leave digital multimeter at ohm shift, connect two
meter pen to two pins of primary winding, the
resistance value is 0.42- 0.58Ωwhen it is 20℃;
secondary winding resistance value is 11.2-
14.8kΩ.

Chart 3-18 Exterior Drawing of Ignition

Coil

Connect To Main

Relay Pin No.87

Chart 3-19 circuit Diagram of Ignition

Coil

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3.11 CARBON CANISTER SOLENOID VALVE

1)Exterior drawing and pin definition

Canister control valve only has two pins; one is
connect to No.87 pin of main relay output end; and
another pin connected to No. 5 pin of ECU.

2)Installation position: Canister vacuum pipe of
intake manifold

3)Purpose: Control the quantity of the cleaning
flow from canister to air intake chief pipe. The
absorption of the canister is limited so if the
gasoline vapor adhesive to canister can not be
consumed the gasoline vapor will volatility to
outside and pollute the air.

4)Working principle

Canister is made up of electromagnetic coil,
armature and valve etc.. There is strainer on the
intake. The flow quantity passes canister valve is
correlate not only to electrical impulse duty ratio of
canister control valve output by ECU, but also to
the pressure difference between canister valve
intake and outlet. When there is no electronic
impulse, the canister control valve will shut down.

5)Working voltage:9—16V

Working temperature:-30--120℃

6)Malfunction and diagnosis method

l Malfunction: Function invalidation.

l Reason: some particle coming to inside of valve

causes erosion or poor sealing.

l Service notice: 1, let the airflow direction be

accord with the regulation; 2, when there are
black particle inside of valve and causes the
control valve invalidation, the valve need to be
changed, please check the canister working
conditions; 3, avoid the water, fuel and other
liquid into valve during the service; 4, hang the
valve on the tube to avoid the transferring of
solid sound.

l Simple measurement method: (disassemble the

Chart 3-20 Exterior Drawing of Canister

Solenoid

Connect To Main Relay

Canister Solenoid Valve

Chart 3-21 Circuit Diagram of Canister

Solenoid

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joint) leave digital multimeter to ohm shift, two
meter pen connect to the pins of canister valve,
it is 26±4 Ω when it is 20

.

℃

3.12 FUEL PRESSURE REGULATOR

1)Exterior drawing

2)Installation position: Fuel bracket assembly

3)Purpose: Adjust the pressure inside of fuel pipe,
keep the System pressure around 350Kpa.

4)Working principle: See chart 3- 23, one piece of
flexible film made up of rubber and fiber separate the
fuel pressure regulator into two compartments. The
upper compartment communicates to the air, and
there is spring inside. The lower compartment is full
of fuel entering from the fuel intake under the fuel
pressure regulator. The lower part of the film gets the
pressure from fuel and the upper part gets the pressure
from air and spring. The film can distort and drive
valve seat making the valve open and close, but the
distortion is smaller the acting force of the spring may
be seemed as not changed. So the opening and closing
of the valve is decided by the pressure difference of
the fuel pressure from lower compartment and the air
pressure from the upper compartment. If the valve is
closed at first, then the fuel pressure increased
causing the pressure difference between upper and
lower compartments increased. At last the film was
raised up by the fuel pressure and valve is opened.
The fuel return to fuel tank from oil return port of
pressure regulator, the fuel pressure decreased until
the valve is closed. If the engine changes its working
conditions now, the pressure difference of fuel system
and the air pressure is about the same.

5)Malfunction and diagnosis method

l Malfunction: fuel pressure is too high or too low,

difficult to start.

l Reason: long time using without maintenance

causing: 1, strainer jammed; 2, particle causes big
leaking; 3, man made mechanical damages.

l Service notice: 1, prohibit to use high pressure air

blowing film element; 2, Forbid using strong

Chart 3-22 Fuel Pressure Regulator

Chart 3-23cutaway View of Fuel

Pressure Regulator

A