Chery A21 2005, Service Manual, Page: 346 / 475

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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