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8. Idle speed too high at hot status
(1) Symptom
The engine runs at fast idle during cold start and remains fast idle at hot status, leading to excessively fast
idle.
(2) Causes and Troubleshooting
a. The initial idle value is not properly adjusted,
b. High system fuel pipeline pressure, need to be adjusted;
c. Water temperature sensor fault, repair or replace it;
d. Water temperature switch and thermostat fault, repair or replace it;
e. Idle control valve fault, repair or replace it;
f. Throttle is binding and not tightly closed, repair or replace it;
g. Fuel evaporation control valve is always open, repair or replace it;
h. Speed sensor fault, repair or replace it.
9. Idle fluctuation
(1) Symptom
when idling, the engine speed fluctuates.
(2) Causes and Troubleshooting
a. Intake pressure temperature sensor fault, repair or replace it;
b. Check valve is damaged and needs to be replaced;
c. Water temperature sensor , water temperature switch and thermostat is poorly coordinated, repair,
adjust and troubleshoot them;
d. Oxygen sensor fault, need to be replaced;
e. Spark plug poor connection, repair or replace it;
f. Idle control valve and its control circuit fault, repair or replace it;
g. Idle switch is not closed, need to be repaired.
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