Suzuki Grand Vitara JB416 / JB420 / JB419. Manual - part 135

1D-66 Engine Mechanical: For J20 Engine

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Engine Mechanical: For J20 Engine 1D-67

Air Cleaner Element Introduction

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This air cleaner element is dry type. Remember that it needs cleaning according to “Air Cleaner Filter Inspection and 
Cleaning: For J20 Engine”.

IMT (Intake Manifold Tuning) System Description

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IMT (Intake manifold tuning) system consists of the following items:
• IMT valve (5) fixed on intake manifold (1)
• IMT valve actuator (4)
• IMT vacuum solenoid valve (2)
• Vacuum tank (3)
Vacuum tank contains the one way check valve (6) to maintain negative pressure constantly regardless of variation in 
the intake manifold pressure.
Vacuum tank, therefore, supplies IMT vacuum solenoid valve actuator with stable negative pressure in whole engine 
speed ranges.

1

2

3

4

5

6

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1D-68 Engine Mechanical: For J20 Engine

IMT (Intake manifold tuning) system varies effective length of intake pipe by opening and closing IMT valve in order to 
improve air volumetric efficiency.
As intake valve in cylinder head is opened and closed repeatedly, intake air pulsation always exists. If intake valve is 
opened when air pressure is momentarily maximum, intake air volumetric efficiency is increased. This momentary 
maximum air pressure depends on effective intake pipe length.

When IMT valve is fully open [A]:
The effective intake pipe length is shorter. Engine torque between middle and high engine speed ranges is improved, 
whilst it drops between low and middle engine speed ranges.

When IMT valve is totally closed [B]:
The effective intake pipe length is longer. Engine torque between middle and high engine speed ranges drops, while it 
is improved between low and middle ranges.

IMT system utilizes this characteristic of engine. IMT valve is closed between low and middle engine speed ranges, 
and opened between middle and high engine speed ranges.
In this way, engine torque is improved in whole engine speed ranges.

[B]

[A]:

[A]

[B]:

[A  + B]

3

3

4

4

min

-1

(rpm)

min

-1

(rpm)

2

1

2

1

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[A]: IMT valve open

1. IMT valve

3. Engine torque

[B]: IMT valve closed

2. Intake manifold

4. Engine speed

Engine Mechanical: For J20 Engine 1D-69

System Operation
IMT vacuum solenoid valve open:
When IMT vacuum solenoid valve is OFF, the actuator side of IMT vacuum solenoid valve is lead to relief port. Under 
this condition, the negative pressure is not applied to IMT valve actuator. The IMT valve, therefore, is totally opened 
due to the force of return spring in IMT valve actuator.
The effective intake pipe length, therefore, becomes shorter.
IMT valve closed:
When IMT vacuum solenoid valve is ON, the actuator side of IMT vacuum solenoid valve is lead to vacuum tank. 
Under this condition, the negative pressure of vacuum tank is applied to IMT valve actuator. The IMT valve, therefore, 
is totally closed because the return spring in IMT valve actuator is compressed due to the negative pressure.
The effective intake pipe length, therefore, becomes longer.

Diagnostic Information and Procedures

Compression Check

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Check compression pressure on all 4 cylinders as 
follows:

1) Warm up engine.
2) Stop engine after warming up.

NOTE
After warming up engine, place transmission 
gear shift lever in “Neutral” (shift selector 
lever to “P” range for A/T model), and set 
parking brake and block drive wheels.

 

3) Remove engine cover.
4) Disconnect ignition coil couplers.
5) Disconnect ignition coils (1).
6) Remove all spark plugs (2).

7) Disconnect fuel injector wire harness at the coupler.
8) Install special tool (Compression gauge) into spark 

plug hole.

Special tool
(A):  09915–64512
(B):  09915–64530
(C):  09915–67010

9) Disengage clutch (to lighten starting load on engine) 

for M/T vehicle, and depress accelerator pedal all 
the way to make throttle fully open.

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