Lifan 620. Manual - part 24

9. With normal start, unstable idle speed or flameout under partial load (with A/C on, etc) 
Common trouble location: 

1. A/C system;    2. Idle speed regulator;  3. Fuel injector 

 

Diagnosis Flow 

Table 1-75 

S/N Operation  Test 

Results 

Actions 

Yes Adjust 

1 

Check if the accelerator cable is locked or over 

2 

3 

4 

5 

6 

 
 
 
 
 
 
 
 
 
 
 

97

10. With normal start, idle speed too fast 

Common trouble location: 1. Throttle body and idle speed by-pass air way; 2. Vacuum pipe; 3. Idle 
speed regulator; 4. Coolant temperature sensor; 5. Ignition timing 
 

Diagnosis Flow 

Table 1-76 

S/N Operation  Test 

Results 

Actions 

1 

2 

3 

4 

5 

6 

 

 

 

 

 

 

 

 

 

98

11. Unfavorable rotation speed or flameout during acceleration 

 
Common trouble location:   

1. Fuel with water;   2. Intake air pressure sensor and throttle position sensor; 
3. Spark plug;            4. Throttle body and idle speed by-pass air way;   
5. Intake air way;      6. Idle speed regulator;   
7. Fuel injector;    8. Ignition timing;        9. Exhaust pipe. 

 

Diagnosis Flow 

Table 1-77 

1 

2 

3 

4 

5 

6 

No Next 

step 

7 

Check the fuel for normal operation. 

 

 

Yes Next 

step 

8 

Check if the ignition sequence and timing of the engine 

can meet with the standards. 

No 

Check and repair 

ignition timing 

 

 

 

99

Table 1-77 (Continued) 

S/N Operation Test 

Results

Actions 

Yes Next 

step 

9 

Check the exhaust pipe for smoothness. 

No 

Repair or replace 

exhaust pipe 

Yes Diagnosis 

help 

10 

Connect the electronic injection system adapter. Turn on 

the ignition switch. Check the power supply of the pin 

12#, 13#, 44#, 45#, 63#. Check the grounding of the pin 

Check and repair 

 

 

1 

2 

3 

Yes Next 

step 

4 

Draw out the wire of one of the cylinders, and connect 

with the spark plug. Keep the electrode of the spark plug 

about 5mm from the engine body. Start the engine, and 

and check if the high voltage fire is normal. 

No 

Check and repair 

ignition system 

 

 

 

 

100