Geely CK MR479Q 2007, Workshop Manual

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4. Big fuel consumption
(1) Symptom:
Engine power is ok, but the fuel consumption is big, exhaust pipe discharges black smoke.
(2) Causes and Troubleshooting:
a. When idling, idle speed is high and shall be adjusted;
b. Water temperature sensor fault, service or replace it;
c. Water temperature switch and thermostat fault, repair or replace it;
d. Oxygen sensor fault, repair or replace it;
e. Fuel pressure is big and shall be adjusted;
f. Injector fault (fuel leakage), repair or replace it;
g. Throttle position sensor fault, repair or replace it;
h. Fuel pressure regulator is damaged and shall be replaced;
i. Intake pressure temperature sensor fault, repair or replace it.
5. Unstable idle, liable to be turned off
(1) Symptom:
Engine starts normally, but the idle is unstable regardless of cold or hot status, idle speed is too low and
the engine is liable to be turned off.
(2) Causes and Troubleshooting
a. Poor idle control valve operation, repair or replace it;
b. Low idle speed and faulty or improperly adjusted idle control valve, troubleshoot it;
c. Water temperature sensor fault, repair or replace it;
d. Poor intake system seal, need to be repaired;
e. High voltage spark is too weak, spark plug carbon deposit or electrode clearance is too small, need
to be repaired, cleared and adjusted;
f. Pressure sensor fault, repair or replace it;
g. The compression pressure in the cylinder is too low, need to be serviced;
h. Fuel line pressure is too low, needed to be serviced;
i. Air cleaner is clogged, clean or replace it;
j. Poor injector atomization, fuel leakage, block or big injection variation, need to be repaired;
(3) Diagnosis procedure (Figure 152)
6. Unstable idle at cold status, liable to be turned off
(1) Symptom
During the cold start, idle is unstable and engine is liable to be turned off, the normal idle is recovered
after warming of the engine.
(2) Causes and Troubleshooting
a. Water temperature sensor fault, repair or replace it;
b. idle control valve fault, repair or replace it.