CHERY·A21 SERVICE MANUAL ENGINE EFI SYSTEM
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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
Malfunction: badness idle speed, badness
acceleration, can not start (difficult to start) etc..
Reason: lack of maintenance causes invalid by
the colloid inside of injector became insulation
layer.
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
Relay Pin No. 87
Cylinder No.1, No.2, No.3, No.4
Chart 3-16 Circuit Diagram of Injector
Chart 3-17 Exterior
Sensor
