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Maintenance Manual for J2 Sedan

Electronic Control System

of Engine

232

Trouble phenomenon 6: Normal start-up but unstable idling at any time

General trouble position:

Poor quali

ty of fuel;

2.Fuel in

jector

; 3.Spa

rk plug;

4.Throttle

body and

idle

bypass air

passage;

5.Intake passage; 6.Idle adjustor (step motor ); 7.Ignition timing; 8.Spark plug; 9.Mechanical part

of engine.

General diagnosis procedure:

No.

Operating Steps

Detection

Results

Subsequent Steps

Yes

Repair the intake

system

Check

air

filter

for

blockage

and

intake

passage

for

leakage.

No

Next step

Yes

Wash

replace

Check

idle

adjustor

for

sticking.

No

Next step

Yes

step

Check the spark plug of each cylinder to observe whether its

model

and gap are in compliance with the

specification.

No

Adjust or repla

Yes Wash

Check air throttle body and idle bypass air passage for carbon

deposit.

No

Next step

Yes

Failure of

Replacement

Dismantle the fuel injector and use the

cleaning analyzer special for

fuel injector to check whether there is

leakage, blockage or too poor

flow in the fuel injector.

No

Next step

Yes

Change

fuel

Check fuel condition and observe w

hether the trouble phenomenon

occurs just after adding the fuel.

No

Next step

Yes

Eliminate the

mechanical trouble of

engine

Check pressure of all the cylinders and observe whether

the

pressure difference of each engine cylinders is large.

No

Next step

Yes

step

Check whether the ignition sequence of engine a

nd ignition timing

is in compliance with

specification.

No

Repair ignition

timing

Yes

Diagnosis

help

Turn on the ignition switch and check whether the power supply

and earthing are normal.

No

Repair related

circuit

Brand	JAC
Model	J2
Category	Automobile
Language	English

JAC J2 User Manual

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JAC J2 Specifications

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