11.  Dismantle the fixing bolts of the 

mounting strap in the middle of 
the fuel tank. 

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12.  Dismantle the fixing bolts of the 

mounting strap in the front of the 
fuel tank. 

13.  Lower the fuel tank slowly. 

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14. Disconnect fuel pump harness 

connector. 

15.  Carefully put the fuel tank down.

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Installation Procedure: 

1 

Lift fuel tank assembly. 

2.  Connect the fuel pump wiring 

harness connector. 

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3.  Install and tighten the fixing bolts 

of the mounting strap in the front 
of the fuel tank. 

Torque :42 Nm(Metric) 
31lb-ft(English system) 

4.  Install and tighten the fixing bolts 

of the mounting strap in the 
middle of the fuel tank. 

Torque :42Nm(Metric) 31lb-ft(English 
system) 

5.  Install and tighten the fixing bolts 

of the mounting strap in the rear 
of the fuel tank. 

Torque :42Nm(Metric) 31lb-ft(English 
system) 

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6. Connect the front fueling 

ventilation hose and install the 
fixing clamp. 

7.  Connect the left-front fuel tank 

inlet pipe and the canister hose. 

8.  Fix the canister piping to the fuel 

tank. 

9.  Connect the fuel tank inlet hose 

and fasten the clamp. 

10. Connect the fuel level sensor 

harness connector. 

11. Connect the battery negative 

cable . 

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2.4 Auxiliary Emission Control Device 

2.4.1 Specifications 

2.4.1.1 Fastener specifications 

Torque Range 

Fastener Name 

Model 

Metric (N.m) 

English system 
(lb-ft) 

Fixing Bolts of Canister 
Solenoid Valve Bracket 

M6×12 

8 - 9 

5.9 - 6.7 

Fixing Bolts of Canister 
Assembly 

M8×20 

20 - 24 

14.8 - 17.8 

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2.4.2 Description and Operation 

2.4.2.1 Heated Oxygen Sensor (HO2S) 

Heated Type Oxygen Sensor (HO2S) are installed before and after the three-way catalytic 
converter. Heated oxygen sensor sends signals to the engine control module (ECM) indicating 
oxygen content in the exhaust. the engine control module controls the fuel injectors to change the 
engine Air-fuel ratio. The ideal Air- Fuel ratio is 14.7:1, at this time the catalytic converters is the 
most efficient. As the fuel injection system continuously measures and adjusts Air-Fuel ratio, it is 
called "closed loop" control. 

1. Open-loop 

When the engine has just started and the speed is higher than 400 rpm, the system enter "open 
loop" operation. In the open- loop mode, the engine control module (ECM) ignores the signal 
from the heated type oxygen sensor (HO2S) signal according to signals from the temperature 
sensor of engine coolant (ECT) and intake pressure temperature sensor to calculate the Air-Fuel 
ratio. Sensors will remain in the "open loop" mode, until the following conditions are met: 

z  Heated type oxygen sensor voltage output changes, showing that the temperature is high 

enough and the system can enter the normal operation. 

z  Temperature sensor of engine coolant is higher than the specified temperature. 

z  The engine has been started for the specified period of time. 

2. Closed-loop 

In the above mentioned situation, the specific values depend on different engines and are stored in 
electrically erasable programmable read-only memory (EEPROM). When these conditions are met, 
the system enters into "closed loop" operation. In the "closed loop", the engine control module 
calculates Air-Fuel ratio according to oxygen sensor signals (ie, fuel injector connected timing), so 
that the Air-Fuel ratio is always very close to 14.7:1. 

Notes: 

Once the engine control module confirms oxygen sensor faulty, the system will be immediately in 
"open loop" control. The Air-fuel ratio is no longer adjusted according to the oxygen sensor 
signals. 

2.4.2.2 Evaporative Emission (EVAP) Control System 

Evaporative emission control system uses the basic principle of Canister storage method. This 
method transfers fuel vapor from fuel tank to the carbon storage devices in order to save the steam 
when the vehicle is not running. When the engine is running, the fuel vapor is sucked out from the 
Canister and burnt in the normal combustion process. Gasoline vapor from the fuel tank flows into 
the fuel vapor recovery pipe. The vapor is absorbed by the Canister. After the engine runs the 
required time, the engine control module provides a ground circuit, so that evaporative canister 
clean-up solenoid valve is turned on and the air is drawn into the canister and mixed with vapor. 
The mixture is then sucked into the intake manifold. The evaporative canister clean-up is 
controlled by the pulse-width modulated solenoid valve (PWM) signal to open or close. According 
to the operating conditions determined by air flow, fuel adjustment and intake air temperature, 
evaporative Canister PWM duty cycle changes. The following conditions can cause poor idling, 
stalling and poor performance: 

z  Canister Solenoid Valve Inoperation 

z  Canister Damage 

z  Hose Disconnected, Cracking, Improperly Connected To The Pipeline 

Evaporative canister is an emission control device containing active carbon particles. Evaporative 
Canister is used to store fuel vapor from fuel tank. When certain conditions are met, the engine 
control module will provide the canister solenoid valve power, so that the fuel will be sucked into 
the engine cylinder and burnt off. 

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