With Normal Start, Unstable Idle Speed During Warm-Up - Lifan 620 Maintenance Manual

S/N
Check the pressure for each cylinder of the engine.
7
Are they great different?
Check if the ignition sequence and timing of the
8
engine can meet with the standards.
Connect the electronic injection system adapter.
Turn on the ignition switch. Check the power supply
9 of the pin 12#, 13#, 44#, 45#, 63#. Check the
grounding of the pin 3#, 51#, 53#, 61#, 80#. Are
they OK?

7. With normal start, unstable idle speed during warm-up

Common trouble location:
1. Fuel with water;
4. Throttle body and idle speed by-pass air way;
6. Idle speed regulator;
S/N
Check the air filter for blockage and the intake air
1
way for leakage.
Check the spark plug for each cylinder. Check if its
2
model and gap can meet with starndards.
Remove the idle speed regulator. Check the throttle
3 body, idle speed regulator, and idle speed by-pass
air way for carbon deposition.
Disconnect the coolant temperature sensor, and
4 start the engine. Check the engine under warm-up
for unstable idle speed.
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Table 1-72 (Continued)
Operation
2. Coolant temperature sensor;
7. Mechanical part of the engine.
Diagnosis Flow
Table 1-73
Operation
94
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Test Results Actions
Remove the mechanical
Yes
troubles for the engine
No Next step
Yes Next step
Check and repair ignition
No
timing
Yes Diagnosis help
Check and repair relevant
No
line
3. Spark plug;
5. Intake air way;
Test Results Actions
Check and repair air
Yes
intake system
No Next step
Yes Next step
No Adjust or replace
Yes Wash relevant parts
No Next step
Yes Replace sensor
No Next step