Chery Fora (Elara A520). Manual — part 145

CHERY·A21 SERVICE MANUAL ENGINE EFI SYSTEM

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3 sensor connectors. The rated resistance is
860Ω±10% When it is 20℃

3.6 PHASE

SENSOR

(CAM

SHAFT

POSITIONING SENSOR)

1)Exterior drawing and pin

This sensor has three pins: No. 1 grounding, No.
2 for signal output and No. 3 connecting to
power anode.

2)Installation position: on the valve cover.
There is only one hole on this sensor casing for
tightening M6, and the torque is: 8±0.5Nm.

3)Purpose: This sensor provides crankshaft
phase information to ECU, that is to say, to
separate crankshaft compression top dead center
and exhaust top dead center.

4)Working principle

It is a Hall sensor.

5)Working temperature: -30--130℃

Working voltage: 4.5—16V

Trigger gap: 0.1—1.8mm

6)Malfunction and diagnosis method

l Malfunction: can not start, emission exceed

standard, fuel consume increased.

l Reason: Man made.

l Simple measuring method: (connect the

joint) switch on ignition switch but do not
start the engine; put digital multimeter on
DC volt, connect two meter pen to No. 3
and No. 1 sensor connectors and make sure
there is 12V reference voltage. Start the
engine, checking if it is in good conditions
of No. 2 pin by oscillograph on vehicle.

Chart 3-10 Exterior drawing of phase

sensor

Chart 3-10 Exterior drawing of phase

sensor

Phase sensor

Connect to main relay

Grounding point

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3.7 ELECTRIC FUEL PUMP

1)Exterior drawing and pin

The electric fuel pump has two pins connecting
to pump relay. There are “+”and “-” showing
anode and cathode on the pump housing near to
pins.

2)Installation position: inside fuel tank

3)Purpose: Deliver the fuel to engine fuel
supplying pipe at certain flow and fuel pressure
and keep the stable fuel pressure (realized by
fuel pressure regulator)

4)Working principle

The electric fuel pump is made up of DC
electromotor, vane pump and end cover (it’s an
integration of check valve, relief valve and an
anti electromagnetic interference element).
Pump and electromotor are coaxial assembly
and within the same casing. The pump and
electromotor are full of gasoline for coolant and
greasing inside of the casing. The accumulator
provide power to electric fuel pump via fuel
pump relay, and the relay switches on electric
fuel pump only when engine starting and
running. When the engine stops for some reason,
the pump will stop to run by itself.

5)Working voltage:8—14V

Working temperature:-30--70℃

System pressure: 300KPa

6)Malfunction and diagnosis method

l Malfunction: big running noise, badness

acceleration, can not start (difficult to start)
etc..

l Reason: use of low quality fuel and cause 1,

colloid became insulation layer; 2, fuel
pump bushing and armature come to
together; 3, components of fuel level sensor
eroded.

l Service notice: 1, the electric fuel pump can

Chart 3-12 Exterior Drawing of Electric

Fuel Pump

Chart 3-10 Exterior Drawing Of Phase

Sensor

Power Supply

Electric Fuel Pump

Fuel Pump Relay

Connect

To Main

Relay

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has different flow according to the
requirement of engine, but with the same
exterior looking.

The pump which can be assembled to perhaps
is not the fittest. For service the replaced
electric fuel pump must has the same part
number as the original pump; 2, do not change
the pump at dry status to prevent the pump
from accident; 3, when it needs changing fuel
pump, please clean fuel tank and fuel filter.

l Simple measuring method: (disconnect joint)

leave digital multimeter at ohm shift, connect
two meter pen to two pins of pump, measure
the resistance, it is not zero or infinite(that is
non short circuit, open circuit).(connect the
joint)connect the fuel pressure meter to fuel
intake pipe and start the engine, observing if the
fuel pump works; If it is not running, check if
there is power or not on the pin of”+”; if it is
running, at the condition of idle speed, check
the fuel pressure if it is around 260kPa; plug
off the fuel pressure regulator vacuum pipe if it
is around 300kPa.

3.8 ELECTROMAGNETIC INJECTOR

1)Exterior drawing and pin

There are two pins on each injector. One of them is
No. 87 pin aside of casing marked with plus and
connected to main relay output; and another one
connect with ECU No. 27,6,7,47 pins.

2)Installation position: On the air intake manifold
near

the

end

of

air

intake

port.

When

you .disassemble and reassemble the fuel injector
the O ring must be changed. And pay attention not
to damage the sealing surface of the injector.

3)Purpose: Inject some fuel to its correspondent
cylinder at proper time to meet the engine
requirement of different power and different torque.

4)Working principle: ECU sends electrical
impulse to injector coil and form magnetic field
force. When magnetic field force increase to

Chart 3-14 Exterior Drawing of Injector

1, O Ring

2, Screen

3, Injector with Elec. Plug

4, Coil

5, Spring

6, Valve Pin with Coil Armature

7, Valve Seat with Injection Hole

Chart 3-15 Cutaway View Of Injector

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conquer Return spring pressure, needle valve
gravity and friction force, the needle valve begin to
rise up and start the injection process. The pressure
of return spring makes needle valve close again
when the injection impulse is stopped.

5)Working voltage:6—16V

Working injection pressure: 350KPa

6)Malfunction and diagnosis method

l Malfunction: badness idle speed, badness

acceleration, can not start (difficult to start) etc..

l Reason: lack of maintenance causes invalid by

the colloid inside of injector became insulation
layer.

l Simple measure method: (disconnect the joint)

leave digital multimeter at ohm shift, connect the
meter pen to the two pins of injector. The rated
resistance should be 11 - 13Ωwhen it is 20

.

℃

3.9 AIR FLOW SENSOR

1)Exterior drawing and pin definition

This sensor is 5 pins: No. 1 is intake temperature
pressure signal; No. 2 is accumulator pressure; No. 3
is grounding; No. 4 is reference voltage 5V; No. 5 is
intake airflow signal output.

2)Installation position

It is behind the air cleaner of the air intake tube.

3)Purpose:

This sensor is hot cable airflow sensor, which check
the temperature and air intake flow entering to
cylinder and provide evidence to ECU to calculate
fuel injection quantity.

4)Working principle

If there are no airflow passing when the air quality
and flow meter works, temperature grads of both
sides of the heating area spread symmetry, and
temperature of these two points are same. When the
air passes here just one way, the air will be heated
when it passes the central heating area and this will

Connect

To

Main

Relay Pin No. 87

Cylinder No.1, No.2, No.3, No.4

Chart 3-16 Circuit Diagram of Injector

Chart 3-17 Exterior Drawing of Airflow

Sensor