Chery A18. Manual — part 25

9) Unstable idle speed after engine warm-up

Yes

Fix the indicated

malfunction.

1

Turn the ignition switch to “ON” position.
Inspect with the diagnostic tester to see
whether

there

is

any

malfunction

information record.

No

Proceed to next step.

Yes

Proceed to next step.

2

Turn the ignition switch to “ON” position
and connect the adaptor between ECU and
the wiring harness. Verify that the
voltages at following ECU’s pins such as
absolute pressure sensor output of air
intake manifold, air intake temperature
sensor output, coolant temperature sensor
output, oxygen sensor output and ECU’s
output voltage connected to idle actuator’s
pin are normal.

No

Repair or replace the

wiring harness and

relevant parts.

Yes

Proceed to next step.

3

Shut down the engine and verify that the
air filter is free of any blockage.

No

Replace

Yes

Proceed to next step.

4

Verify that the air intake manifold
pressure is maintained between 35-65 kPa
at idle speed.

No

Fix the leakage of air

intake system

Yes

Proceed to next step.

5

Connect the fuel manometer valve (the
connecting points will depend on the types
of car models). Short the 30# and 87# pins
of the fuel pump relay to operate the fuel
pump in order to verify that the fuel
pressure is maintained at about 350kPa.

No

Proceed to Step 9

Yes

Proceed to Step 8

6

Provide a voltage supply of 12V with
special connector between the battery and
the fuel injector, and verify that the fuel
injector is functioning normally.

No

Proceed to next step.

Yes

Replace

7

After washing and cleaning the fuel
injector, inspect again to see whether it
can function normally.

No

Replace the fuel

injector.

Yes

Replace the fuel.

8

Verify that the fuel is deteriorated or
contaminated with water.

No

Proceed to Step 14.

Yes

Proceed to next step.

9

Verify that the fuel pressure is lower than
350kPa.

No

Proceed to Step 13.

Yes

Proceed to next step.

10

Turn off the fuel manometer valve.
Connect the ignition switch again to
re-operate the fuel pump in order to verify
that the fuel pressure can be established.

No

Proceed to Step 12.

11

Turn on the fuel manometer valve and
clamp the fuel return pipe with the fuel

Yes

Replace the fuel

pressure regulator.

tube clamp to stop the fuel return in order
to verify that the fuel pressure can be
established quickly.

No

Repair or replace the

fuel injector or the fuel

pipe.

Yes

Repair or replace the

fuel air inlet pipe.

12

Verify that the fuel inlet pipe has any
leakage or blockage.

No

Replace the fuel pump.

Yes

Repair or replace the

fuel return pipe.

13

Verify that the fuel return pipe has any
leakage or bending.

No

Replace the fuel

pressure regulator.

Yes

Proceed to next step.

14

Run the engine at idle speed until the
coolant temperature reaches its normal
value in order to verify that the ignition
advance angle is normal.

No

Adjust the ignition

advance angle.

Yes

Replace the coolant
temperature sensor.

15

Disconnect the coolant temperature sensor
to verify that the engine is normal.

No

Proceed to next step.

Yes

Proceed to next step.

16

Verify that the compression pressure of
engine cylinder is normal.

No

Fix the malfunction.

Yes

Proceed to next step.

17

Verify that the resistance of each cylinder
high voltage cable is normal.

No

Replace

Yes

Replace

18

Verify that the ignition coil and high
voltage cable have any damage parts or
cracks.

No

Proceed to next step.

Yes

Replace the ECU.

19

Verify that the spark plug is normal.

No

Replace the spark plug.

10) A/C system malfunction

Yes

Proceed to next step.

1

Verify that there is enough refrigerant and
the A/C belt, A/C clutch and pressure switch
are in good condition.

No

Fix the malfunction.

Yes

Fix the indicated

malfunction.

2

Run the engine at idle speed and turn on the
A/C switch. Inspect with the diagnostic
tester to see whether there is any
malfunction with the A/C thermo-sensitive
resistance.

No

Proceed to next step.

Yes

Proceed to next step.

3

Turn on the A/C switch and connect the
adaptor between ECU and the wiring
harness. Measure and see whether the
ECU’s A/C switch and A/C pressure have
any signal input.

No

Inspect the wiring

harness.

Yes

Replace the bulb or

repair the wiring

harness.

4

If the car is controlled by low electrical
level, verify that the A/C still functions
when it is turned off.

No

Proceed to next step.

Yes

Repair the A/C relay

and the wiring

harness.

5

Verify that there is any low level output
from the ground terminal of A/C relay
solenoid coil in ECU.

No

Replace the ECU.

11) Periodically instability (the memory has to be restored after ECU’s
power-off)

Yes

Fix the indicated

malfunction.

1

Turn the ignition switch to “ON” position.
Inspect with the diagnostic tester to see
whether

there

is

any

malfunction

information record.

No

Proceed to next step.

Yes

Proceed to next step.

2

Verify that the air filter is free of any
blockage.

No

Replace

Yes

Proceed to next step.

3

Verify that the air intake pressure is
maintained between 35-65 kPa at idle
speed.

No

Overhaul air intake

system and leakage.

Yes

Proceed to Step 7

4

Run the engine at idle speed and cut off
the cylinder one by one in order to verify
that the speed is decreased and fluctuated.

No

Proceed to next step.

Yes

Proceed to next step.

5

Turn the ignition switch to “ON” position
and connect the adaptor between ECU and
the wiring harness. Verify that the
voltages

at

following

ECU’s

pins

including absolute pressure sensor output
of air intake manifold, air intake
temperature

sensor

output,

coolant

temperature sensor output, oxygen sensor
output, electronic grounding, ignition
switch pin, and ECU’s pins of 65#, 64#,
67#, and 66# (output connected to idle
actuator) are normal.

No

Repair or replace the

wiring harness.

Yes

Proceed to next step.

6

Run the engine at idle speed until the
coolant temperature reaches its normal
value in order to verify that the ignition
advance angle is normal.

No

Inspect other items.

Yes

Clean

7

Verify that the sensing holes of air intake
manifold pressure sensor and air intake
temperature sensor have any blockage.

No

Proceed to next step.

Yes

Replace the fuel.

8

Verify that the fuel is deteriorated or
contaminated with water.

No

Proceed to next step.

Yes

Proceed to next step.

9

Apply a voltage supply of 12V directly
between the battery and the fuel injector
with special connector, and verify that the
fuel injector functions normally.

No

Overhaul the fuel

injector and relevant

wiring harness.

Yes

Proceed to next step.

10

Verify that the resistance of each cylinder
high voltage cable is normal.

No

Replace

11

Verify that the ignition coil and high

Yes

Replace