Suzuki Grand Vitara JB416 / JB420 / JB419. Manual - part 119

1D-2 Engine Mechanical: For M16A Engine with VVT

Camshaft Position Control (VVT Variable Valve Timing) System Description

S6JB0A1411002

System Description
The VVT system is an electronic control system which continuously vary and optimize the intake valve timing in
response to the engine operating condition.
The optimized intake valve timing produce such an air intake with high efficiency that both the higher power generation
and lower fuel consumption can be attained in the whole engine speed range from low to high. In the area of the
average engine load, low emission of nitrogen oxides (NOx) and high fuel efficiency can also be attained by making
the valve opening overlap between the intake and exhaust valves longer.
For the brief of the system operation, the intake valve timing is varied by the cam timing sprocket (1) which varies the
rotational phase between the intake camshaft (3) and sprocket. The rotor (2) in the cam timing sprocket is actuated by
switching or adjusting the hydraulic pressure applied to the chambers for the timing advancing (7) and/or retarding (6).
To switch or adjust the hydraulic pressure appropriately, ECM operates the oil control valve (12) with detecting the
engine speed, intake air value, throttle opening, engine coolant temperature and camshaft position (angle).

60˚ (variable angle)

Most retarded timing

Most advanced timing

Exhaust valve

Intake valve

Crank angle

Overlap of valves

alv

e lift

I3RH0B140002-01

4. Oil passage to chamber for timing retarding

8. Oil filter

10. Oil pan

12. Oil flow

5. Oil passage to chamber for timing advancing

9. Oil pump

11. Control signal from ECM

Engine Mechanical: For M16A Engine with VVT 1D-3

Oil Control Valve
The oil control valve switches and adjusts the hydraulic
pressure applied to the cam timing sprocket by moving
the spool valve (1) according to the duty pulse signals
output from the ECM. By this operation, the intake valve
timing is varied continuously. Signals output from the
ECM are the duty pulse of about 240 Hz.

Cam Timing Sprocket
The cam timing sprocket is equipped with the chambers
for timing advancing (2) and retarding (3) which are
separated by the rotor (5). The rotor rotates receiving the
hydraulic pressure applied to both the chambers. The
sprocket (1) is installed on the housing (4) and the rotor
is secured on the intake camshaft by fastening the bolts.
Therefore, the actuation of the rotor makes the phase
difference between the sprocket and intake camshaft.

Timing Advancing
When the duty ratio of the signal output from the ECM is
heavy, the spool valve (4) of the oil control valve moves
to the left (opposite direction against the coil (5)). By this
spool valve movement, the pressurized oil (1) is led into
the chambers for timing advancing and the oil in the
chambers for timing retarding is drained. This operations
actuate the rotor (3) and result in the advanced timing of
the intake valve.

Timing Holding
When the duty ratio of the signal output from the ECM
shows that of holding, the spool valve of the oil control
valve is located at hold position. Because this condition
generates no oil pressure changes in both chambers,
the rotor is fixed at a target position.

Timing Retarding
When the duty ratio of the signal output from the ECM is
light, the spool valve of the oil control valve moves to the
right (head for the coil). By this spool valve movement,
the pressurized oil is led into the chambers for timing
retarding and the oil in the chambers for timing
advancing is drained. This operations actuate the rotor
and result in the retarded timing of the intake valve.

6. Seal

I3RH0B140003-01

I3RH0B140004-01

2. Drain

1 2

I3RH0B140005-01

I3RH0B140006-01

I3RH0B140007-01

1D-4 Engine Mechanical: For M16A Engine with VVT

Targeted Timing Varying Operation

Diagnostic Information and Procedures

Compression Check

S6JB0A1414001

Check compression pressure on all 4 cylinders as
follows:

1) Warm up engine to normal operating temperature.
2) Stop engine after warming up.

NOTE
After warming up engine, place transaxle
gear shift lever in “Neutral”, and set parking
brake and block drive wheels.

3) Disconnect ignition coil couplers (1).
4) Remove ignition coil assemblies (2) with high-

tension cord (3).

5) Remove all spark plugs.
6) Disconnect fuel injector wires (4) at the coupler.

Driving condition

Valve timing

Target of control

Effect

Engine running at idle
speed

Most retarded

To shorten the valve opening overlap in
order to prevent the exhaust gas
counterflow to intake manifold.

Stabilization of the engine
rotation at idle speed.

Average engine load
range

To the advanced
side

To lengthen the valve opening overlap
in order to enhance the internal
exhaust gas recirculation and reduce
the pumping loss.

Improvement of the fuel
efficiency.
Lowering of the exhaust
emission.

Light engine load
range

To the retarded side

To shorten the valve opening overlap in
order to prevent the exhaust gas
counterflow to intake manifold.

Keeping of the engine stability.

Low or average
engine speed range
with heavy engine
load

To the advanced
side

To advance the closing timing of the
intake valve in order to improve the
volumetric efficiency.

Improvement of generating the
engine torque at low and
average engine speed.

High engine speed
range with heavy
engine load

To the retarded side

To retard the closing timing of the
intake valve in order to improve the
volumetric efficiency.

Improvement of generating the
engine power.

Low engine coolant
temperature

Most retarded

To shorten the valve opening overlap in
order to prevent the exhaust gas
counterflow to intake manifold and
reduce the fuel increasing.
To slow the fast idle speed of the
engine as a result of stabilizing the
engine idling.

Stabilization of the fast idling of
the engine.
Improvement of the fuel
efficiency.

At engine starting and
stopping

Most retarded

To shorten the valve opening overlap in
order to prevent the exhaust gas
counterflow to intake manifold.

Improvement of start ability.

I2RH0B140003-01

Engine Mechanical: For M16A Engine with VVT 1D-5

7) Install special tools (Compression gauge) into spark

plug hole.

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

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

for M/T vehicle, and depress accelerator pedal (1) all
the way to make throttle fully open.

9) Crank engine with fully charged battery, and read the

highest pressure on compression gauge.

NOTE

• For measuring compression pressure,

crank engine at least 250 r/min. by using
fully charged battery.

• If measured compression pressure is

lower than limit value, check installation
condition of special tool. If it is properly
installed, possibility is compression
pressure leakage from where piston ring
and valve contact.

Compression pressure
Standard: 1400 kPa (14.0 kg/cm

, 199.0 psi)

Limit: 1100 kPa (11.0 kg/cm

, 156.0 psi)

Max. difference between any two cylinders: 100
kPa (1.0 kg/cm

, 14.2 psi)

10) Carry out Steps 7) through 9) on each cylinder to

obtain 4 readings.

11) After checking, install spark plugs and ignition coil

assemblies (2) with high-tension cord (3).

12) Connect ignition coil couplers (1).
13) Connect fuel injector wires (4) at the coupler.

Engine Vacuum Check

S6JB0A1414002

The engine vacuum that develops in the intake line is a
good indicator of the condition of the engine. The
vacuum checking procedure is as follows:

1) Warm up engine to normal operating temperature.

NOTE
After warming up engine, be sure to place
transaxle gear shift lever in “Neutral”, and set
parking brake and block drive wheels.

2) Stop engine and turn off the all electric switches.
3) Remove PCV hose (1) from PCV valve (2).

(A)

(C)

(B)

I3RH0B140009-01

I5JB0A141001-02

I2RH0B140003-01

I3RH0B140011-01

Content .. 117 118 119 120 ..