Geely FC Workshop Manual page 39

CO HC
Normal High
Low High
High High
28
Engine mechanism - Engine assembly
Trouble occurrence
Unstable idle speed
Unstable idle speed
(HC readings not stable)
Unstable idle speed
(black smoke emission)
Possible causes
1. Ignition system malfunction
Ignition timing incorrect
Spark plug too dirty, short circuit or clearance
incorrect
2. Valve clearance incorrect
3. Air inlet and exhaust valve leaky
4. Cylinder leaky
1. Vacuum leak:
PCV hose
Intake manifold
Throttle body
Idle speed stepping motor
Vacuum booster and pipelines
2. Fire caused by too thin mixing ratio
1. Air filter core blocked
2. PCV valve blocked
3. EFI system malfunction
Fuel pressure regulator malfunction
Water temperature sensor malfunction
Intake pressure sensor malfunction
ECU malfunction
Injection nozzle malfunction
Throttle position sensor malfunction