77IV. Exhaust Pipe Discharges Gas with Abnormal Color (or odor)When there is failure in engine combustion system, the exhaust pipe discharges gas with abnormal color.
1. The discharged gas is thickly black
This is caused by incomplete combustion. Since the mixed air is too thick, the combustion is not complete and
part of the fuel is discharged without combustion, leading to decrease of engine power. At this moment, you
should check fuel pressure regulator, throttle position sensor, injector and ECU system and correct the
problems in time.
2. Exhaust is blue and stinks
This is caused by large amount of oil vapor mixed in the exhaust gas that enters in the cylinder and partici-
pates in combustion. One of the primary reasons is that the piston oil ring is dirty and damaged, and shall be
replaced; another reason may be the failure of valve oil seal or excessive clearance between the valve stem
and guide bush hole resulting in oil entering the combustion chamber for combustion, oil seal or valve guide
bush shall be replaced to resume normal condition.
3. Exhaust is white
This is caused by water or fuel vapor mixed in the exhaust. The primary reason is that cylinder head gasket
is damaged, resulting in slow infiltration of coolant into cylinder and the water vapor entry into the exhaust
pipe after combustion, cylinder head gasket shall be replaced to resume the normal condition.Section 3 Engine Noise Diagnosis and TroubleshootingAbnormal sounds generated during engine operation (e.g. knocking sound, chuckle, hiss, rattle) are called
noise.
Engine noise is primarily generated in valve train, connecting rod piston crankshaft components and other
accessory system. The following description discusses the diagnosis and troubleshooting of the noise gener-
ated in valve train and crankshaft connecting rod mechanism.I. Diagnosis and troubleshooting of the noise in valve trainvalve train consists of intake & exhaust camshaft , valve, valve bushing, tappetand counter gear.
1. camshaft noise
(1) camshaft end play is excessively big (normal intake camshaft : 0.030~0.085mm, exhaust camshaft : 0.
035~0.090mm) , when it exceeds 0.11mm and noise is generated, replace it;
(2) Camshaft bend is another cause for noise; it shall be aligned or scraped. ;
(3) Camshaft journal is excessively worn, resulting in big radial clearance between camshaft and bearing and
noise, replace it;
2. Valve group knock noise
(1) Valve noise is caused by excessive valve clearance, the valve spring seat flange is damaged and shall be
replaced;
(2) Valve spring knock noise is caused by broken valve spring. It shall be replaced;
172II. LOCATION OF HARHESS MULTI-PIN PLUG-IN TERMINAL(1) HINT:
R -- RE Bl -- BLUE Y -- YELLOW
B -- BLACK P -- PIN G -- GREEN
W -- WHITE O -- ORANGE Gr -- GRAY
Br -- BROWN V -- VIOLETL g -- LIGHT GREEN
The first letter represents the base color
The second letter represents the color of the stripe
e.g. VG (violet & green) V-violet, G-greenColor of connector A is white, and B is blackVG
303Figure 6 A/C System Electrical Appliance DiagramIII. Protecting Device1. Low temperature protection
Evaporator temperature sensor, when the sensed temperature is lower than 3°C, the compressor clutch
is de-energized and stops operation.
2. High temperature protection
Water temperature sensor, when the sensed water temperature reaches 109°C, the compressor clutch is
de-energized and stops operation.
3. Low pressure protection
When pressure sensed by the pressure switch is lower than 0.25MPa, the compressor clutch is de-
energized and stops operation.
4. Voltage protection
When the pressure sensed by the pressure switch reaches 1.7MPa, radiator fan rotates.
5. High pressure protection
When the pressure sensed by the pressure switch reaches 2.6MPa, the compressor clutch is de-energized
and stops operation.
6. Normal pressure
When system pressure reaches 0.25MPa~2.4MPa, control the A/C idle speed. Color of wire:R-Red Bl-Blue Y-Yellow Lg-Light green Br-Brown B-Black P-Pink G-Green W-White Gr-Gray
1. Battery 2. Main Fuse Box 3. Alternator 4. Ignition Switch 5. Idle Rise Valve 6. Blower 7. Relay
8. Blower Regulating Resistance 9. Blower Switch 10. A/C Switch 11. A/C Low Pressure Switch
12. Compressor 13. Condensor Fan 14. Radiator Fan 15. A/C High Pressure Switch
16. Water Temperature Sensor 17. Evaporator Temperature Sensor 18. Electronic Wind Door Actuator Switch
19. Electronic Wind Door Actuator 20. Revolution Sensor 21. Engine ECU
