Lifan 620. Manual - part 17

Table 1-52  (Continued)

 

S/N Operation Test 

Results 

Actions 

Yes 

Replace or repair fuel intake 

pipe 

15 

Check the fuel intake pipe for leakage or blockage. 

No 

Replace fuel pump 

Yes 

Repair or replace fuel return 

pipe 

16 

Check if the fuel return pipe is blocked or bent. 

No 

Replace fuel pressure 

regulator 

 

1 

2 

Yes Next 

step 

3 

Disconnect the fuel pipe, and turn the ignition switch. 

Check if the pressure of the fuel system still keeps 

between 150kPa and 200kPa after 1 hour. 

No 

Repair fuel system leakage 

Yes 

Replace fuel pressure 

regulator (inbuilt) 

4 

Connect the fuel pipe. Block the fuel return pipe, and 

turn off the fuel pressure gauge valve. Turn off the 

ignition switch. Check if the pressure of the fuel 

system still keeps between 150kPa and 200kPa after 

1 hour. 

No Next 

step 

 

69

Table 1-53  (Continued)

 

S/N Operation Test 

Results 

Actions 

Yes 

Replace fuel injector and fuel 

pipe  

5 

Check the fuel injector and the fuel pipe for leakage. 

No Next 

step 

Yes 

Check the coolant 

temperature and line 

6 

Take out the water temperature sensor, and start the 

engine. Is the engine OK? 

No Next 

step 

7 

8 

9 

1 

instrument. 

Yes Next 

step 

2 

Check the air filter for smoothness. 

No Replace 

Yes Next 

step 

3 

After successful start, check if the intake air manifold 

pressure is between 35 kPa and 65kPa at idle speed.

No 

Remove leakage for the air 

intake system 

4 

Gently step on the throttle, and check if the vehicle 

can be started easily. 

Yes 

Check and replace throttle 

and idle speed passage 

 

70

Table 1-54  (Continued 1) 

S/N Operation Test 

Results 

Actions 

Yes Next 

step 

5 

Connect the fuel pressure gauge valve. Short-circuit 

the pin 30 and the pin 87 of the fuel bump relay, and 

run the fuel pump. Check if the fuel pressure is about 

300kPa. 

No 9 

Yes 8 

6 

Connect the battery and the fuel injector with a special 

connector. With the voltage supply of 12V, check the 

fuel injector for normal operation. 

No Next 

step 

7 

8 

9 

15 

the following pins of the ECU. Is the voltage of the pin 

J1-12 (crankshaft position sensor) is about 12V? Is 

the empty pin and the pin J1-54 (idle speed stepper 

motor A+) is 0V? 

No 

Check harness and interface

Yes Next 

step 

16 

Keep the engine at idle speed. After the coolant 

reaches normal temperature, ground the pin 51 of the 

ECU with a short-connected line. Check if the ignition 

advance angle is a 6.75° crank angle. 

No 

Adjust ignition advance 

angle 

 

71

Table 1-54  (Continued 2) 

S/N Operation Test 

Results 

Actions 

Yes Next 

step 

17 

Check if the compressed pressure of the engine 

cylinder is normal. 

No 

Remove the trouble 

Yes 

Repair or replace 

18 

Check if the intake air manifold absolute pressure and 

temperature sensor is blocked. 

No Next 

step 

Yes Replace 

ECU 

19 

Check if the coolant temperature sensor for normal 

operation. 

No 

Repair or replace 

 

1 

2 

3 

4 

5 

6 

7 

8 

connection point is related to the vehicle model). 

Carry out direct grounding for the pin 86 of the fuel 

pump relay. Turn on the ignition switch and run the 

fuel pump relay and fuel pump. Check if the fuel 

pressure is between 250kPa and 300kPa. 

No 12 

Yes 11 

9 

Connect the battery and the fuel injector with a special 

connector. With the voltage supply of 12V, check the 

fuel injector for normal operation. 

No Next 

step 

 

72