JAC S2. Engine. Service Manual

Engine intake system

Engine intake system 123

(III) Installation

1. Install air filter exhaust pipe assembly

1). Install air filter exhaust pipe to electronic throttle valve, tighten

ring clamp.

Tightening torque: 4

～ 6 N·m

2). Connect respirator connecting hose and air filter exhaust pipe,

fix with steel-belt-type elastic strap.

Tightening torque: 4

～ 6 N·m

3). Connect air filter exhaust pipe and air filter assembly, and
tighten hoop.

Tightening torque: 4

～ 6 N·m

2. Connect battery cathode cable

3. close engine cover

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Engine intake system

Engine intake system 124

V、Air filter bracket

(I) Disassembly

1. Open engine cover

2. Disconnect battery cathode cable, refer to battery cable disconnect and connect

3. Disassemble air filter assembly, refer to air filter

4. Disassemble air filter bracket I

1). Disassemble 2 fixing bolts of air filter bracket

5. Disassemble air filter bracket II

1). Disassemble fixing bolts of air filter
bracket II

(II) Installation

1. Install air filter bracket I

1). Install fixing bolts of air filter bracket

Tightening torque:

～ 12N·m

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Engine intake system

Engine exhaust system 126

2. Install air filter bracket II

1). Install fixing bolts of air filter bracket

Tightening torque:

～ 12N·m

3. Install air filter assembly

4. Connect battery cathode cable

5. Close engine cover

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Engine intake system

Engine exhaust system 127

VI、Intake manifold

(I)Disassembly

1. Open engine cover

2. Disconnect battery cathode cable, refer to battery cable disconnect and connect

3. Disassemble air filter assembly, refer to air filter assembly

4. Disassemble air filter bracket II, refer to air filter bracket II

5. Disassemble electronic throttle valve, refer to electronic throttle valve

6. Disassemble intake manifold

1). Disconnect harness connector of

absolute pressure sensor.

2). Disconnect the connecting
hose of PCV valve.

3). Disconnect the vacuum
servo connecting hose.

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Engine intake system

Engine exhaust system 128

4). Disconnect the connecting hose of valve EGR.

5). Remove 3 fixing bolts of intake manifold bracket, take off
intake manifold bracket.

6). Remove 5 fixing bolts of intake manifold, take off intake
manifold.

(II)Check

1. Check intake hose

1). Check if intake hose is cracked or damaged, if its matching

surface shape is changed, if the seal ring of intake manifold and

intake seal ring of throttle is damaged. If yes, please repair or

replace.

(III)Installation

1. Install intake manifold

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Engine intake system

Engine exhaust system 129

1). Install and tighten fixing bolts of intake manifold.

Tightening torque: (18±1.0)N·

2). Install and tighten bolts of intake
manifold bracket.

Tightening torque: (22.5±2.5)N·m

3). Connect connecting hose of valve EGR

4). Connect vacuum servo connecting hose.

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Engine intake system

Engine exhaust system 130

5). Connect connecting hose of PCV valve.

6). Connect harness connector of absolute
pressure sensor.

2. Install electronic throttle valve

3. II Install air filter bracket II

4. Install air filter assembly

5. Connect battery cathode cable

6. Close engine cover

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Engine ignition system

Engine exhaust system 131

Engine exhaust system

、Summary

(I)structure overview

Break-down table

1. Front exhaust pipe assembly

2. II level Catalyst assembly of

3. I level Muffler assembly of

4. II level Muffler assembly of

5. Thermal baffle I

6. Thermal baffle II

7. Thermal baffle III

8. Seal gasket

9. Seal gasket II

10.

Lifting eye I

11.

Hang soft cushion

12. Heat-resisting locknut

13.1 type all-metal locknut of
hexagon nut

14. Flange face locknut of
hexagon nut

15. Molectron of Hexagon nut
and

flat gasket

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Engine ignition system

Engine exhaust system 132

System description

Aftertreatment of exhaust of three-way catalyst is the efficient way of reducing the concentration of hazardous

substance in exhaust gas. Three-way catalyst can reduce 98% or even more HC, CO and NOx, turn them into H2O, CO2,
N2. But only within small range near engine excess air coefficient λ=1, can reach this high efficiency, goal of λ closed-
loop control is guarantee mixed air is within this range. Closed -loop control system can only work when equipped with
oxygen sensor.

Oxygen sensor monitors oxygen content of exhaust gas at one side of three-way catalyst, thin mixed air(λ>1)produces

sensor voltage at around 100mV, thick mixed air produces sensor voltage at around 900mV. When λ=1, sensor voltage has
one saltus. Λ closed-loop control makes response to input signal(λ>1 means mixed air is too thin, λ<1 means mixed air is
too thick) and modify control variable, producing correction factor as multiplier to correct lasting time of oil injection.

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Engine ignition system

Engine exhaust system 133

(II)torque parameter

Key parts torque table

No.

items

Torque(N·m)

remark

exhaust manifold stud

1
2
±
2

M8×1×12

Q1840816(exhaust manifold bracket bolts )

22.5
±2.5

M8×16

Catalyst thermal shroud nut

1
0
±
1

M6×1

exhaust manifold nut

3
5
±
2

Connecting bolt of catalyst level II and muffler level
I

5
0
±
5

Thermal baffle installation bolts

6
±
1

Exhaust manifold bracket bolts

22.5
±2.5

Connecting bolt of three-way catalyst and exhaust
manifold

4
5
±
7

II、Front exhaust pipe assembly

(I) Disassembly

1. Lift vehicle

2. Disassemble front exhaust pipe assembly

1). Disassemble 2 fixing bolts of front exhaust pipe assembly and

II level catalyst assembly.

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2). Disassemble 2 fixing bolts of front exhaust pipe assembly and
exhaust manifold assembly.

3). Take off front exhaust pipe assembly.

3. Disassemble seal gasket

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Engine ignition system

Engine fuel system 134

1). Take off seal gasket from front exhaust pipe assembly

(II)Installation

1. Install seal gasket

1). Install seal gasket to front exhaust pipe assembly.

2. Install front exhaust pipe assembly

1). Install 2 fixing bolts of front exhaust pipe assembly and exhaust
manifold.

Tightening torque:

6±1N·m

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Engine ignition system

Engine fuel system 135

2). Install 2 fixing bolts of front exhaust pipe assembly and II level
catalyst.

Tightening torque:

6±1N·m

3. Get vehicle down

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Engine ignition system

Engine fuel system 137

III、II level catalyst assembly

(I)Disassembly

1. Lift vehicle

2. Disassemble II level catalyst assembly

1). Disassemble the 1 lifting eye connecting II level catalyst and car
body.

2). Disassemble 2 fixing bolts connecting II level catalyst and
front exhaust pipe assembly.

3). Disconnect rear oxygen sensor and II level catalyst.

4). Disassemble 2 fixing bolts connecting II level catalyst and I
level muffler.

5). Take off II level catalyst assembly.

3. Disassemble seal gasket.

1). Take off seal gasket from II level catalyst.

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Engine ignition system

Engine fuel system 138

(II)Installation

1. Install seal gasket

1). Install seal gasket to II level catalyst

2. Install II level catalyst assembly

1). Install II level catalyst to rubber bearing of car body.

2). Install 2 fixing bolts connecting II level catalyst and front
exhaust pipe assembly.

Tightening torque:

6±1N·m

3). Install rear oxygen sonsor, tighten connecting bolts.

4). Install 2 fixing bolts connecting II level catalyst and I level
muffler.

Tightening torque:

6±1N·m

3. Get the car down

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JAC S2. Engine. Service Manual - part 10