Mitsubishi Grandis. Manual — part 805

EMISSION CONTROL <MPI>

ENGINE AND EMISSION CONTROL

17-61

POSITIVE CRANKCASE VENTILATION
(PCV) VALVE CHECK

M1173001200217

1. Insert a thin rod into the PCV valve from the side

shown in the illustration (rocker cover installation
side), and move the rod back and forth to check
that the plunger moves.

2. If the plunger does not move, there is a clogging

in the PCV valve. In this case, clean or replace
the PCV valve.

EVAPORATIVE EMISSION CONTROL
SYSTEM

GENERAL INFORMATION (EVAPORATIVE
EMISSION CONTROL SYSTEM)

M1173005100524

The evaporative emission control system prevents
fuel vapours generated in the fuel tank from escaping
into the atmosphere.
Fuel vapours from the fuel tank flow through the fuel
tank pressure control valve and vapour pipe/hose to
be stored temporarily in the canister.
When driving the vehicle, fuel vapours stored in the
canister flow through the purge control solenoid
valve and purge port and go into the intake manifold
to be sent to the combustion chamber.
When the engine coolant temperature is low or when
the intake air quantity is small (when the engine is at
idle, for example), the engine control unit turns the
purge solenoid off to shut off the fuel vapour flow to
the intake manifold.
This does not only insure the driveability when the
engine is cold or running under low load but also
stabilize the emission level.

SYSTEM DIAGRAM

AK300022

PCV valve

AC

AK302829AB

Intake manifold

Canister

From
fuel
tank

OFF

ON

Purge
control
Solenoid
valve

Control
relay

Battery

Engine-ECU <M/T> or
Engine-A/T-ECU <A/T>

Air flow sensor

Engine coolant
temperature sensor

Intake air
temperature sensor

Barometric pressure sensor
(with engine-ECU <M/T>
or engine-A/T-ECU <A/T>)

EMISSION CONTROL <MPI>

ENGINE AND EMISSION CONTROL

17-62

COMPONENT LOCATION (EVAPORATIVE
EMISSION CONTROL SYSTEM)

M1173007500313

PURGE CONTROL SYSTEM CHECK

M1173001400437

1. Disconnect the vacuum hose (between purge

control solenoid valve and intake manifold) from
purge control solenoid valve and connect a hand
vacuum pump to the nipple.

2. Plug the vacuum hose.
3. When the engine is cold or hot, apply a vacuum of

53 kPa, and check the condition of the vacuum.

WHEN ENGINE IS COLD
(ENGINE COOLANT TEMPERATURE: 40

°C OR

LESS)

WHEN ENGINE IS HOT
(ENGINE COOLANT TEMPERATURE: 80

°C OR

HIGHER)

PURGE PORT VACUUM CHECK

M1173001500263

1. Disconnect the vacuum hose (between purge

control solenoid valve and intake manifold) from
the purge control solenoid valve and connect it to
a hand vacuum pump.

2. Plug the nipple from which the vacuum hose was

removed.

3. Start the engine.
4. Check that a fairly constant negative pressure is

generated regardless of the engine speed.

5. If no negative pressure is generated, the port is

probably blocked and should be cleaned.

PURGE CONTROL SOLENOID VALVE
CHECK

M1173001700234

NOTE: When disconnecting the vacuum hose,
always make a mark so that it can be reconnected at
original position.

Engine condition

Normal condition

At idle

Vacuum is maintained.

3,000 r/min

Engine condition

Normal condition

At idle

Vacuum is maintained.

3,000 r/min (within 3
minutes after engine
starts)

Vacuum will leak.

AK302830

Purge control
solenoid valve

AC

AK302831

Plug

Vacuum hose

AB

AK302833

Plug

Vacuum hose

AB

AK100011

AC

Vac-
uum

Engine speed (r/min)

EMISSION CONTROL <MPI>

ENGINE AND EMISSION CONTROL

17-63

1. Disconnect the vacuum hose from the solenoid

valve.

2. Disconnect the harness connector.

3. Connect a hand vacuum pump to nipple (A) of the

solenoid valve (refer to the illustration at left).

4. Check airtightness by applying a vacuum with

voltage applied directly from the battery to the
purge control solenoid valve and without applying
voltage.

5. Measure the resistance between the terminals of

the solenoid valve.

Standard value: 30

− 34 Ω (at 20°C)

AK100012 AC

Battery

A

AK100013

Battery voltage

Normal condition

Applied

Vacuum leaks

Not applied

Vacuum maintained

EMISSION CONTROL <MPI>

ENGINE AND EMISSION CONTROL

17-64

CANISTER REMOVAL AND INSTALLATION

M1173004200197

EXHAUST GAS RECIRCULATION
(EGR) SYSTEM

GENERAL INFORMATION (EGR SYSTEM)

M1173005200435

The exhaust gas recirculation (EGR) system lowers
the nitrogen oxide (NOx) emission level.
When the air/fuel mixture combustion temperature is
high, a large quantity of nitrogen oxides (NOx) is
generated in the combustion chamber.

Therefore, this system recirculates part of emission
gas from the exhaust port of the cylinder head to the
combustion chamber through the intake manifold to
decrease the air/fuel mixture combustion
temperature, resulting in reduction of NOx.
The EGR flow rate is controlled by the EGR valve so
as not to decrease the driveability.

OPERATION

The EGR valve is being closed and does not
recirculate exhaust gases under one of the following
conditions.
Otherwise, the EGR valve is opened and recirculates
exhaust gases.

• The engine coolant temperature is low.

• The engine is at idle.

• The throttle valve is widely opened.

Pre-removal and Post-installation Operation
Air Cleaner assembly Removal and Installation (Refer to
GROUP 15, Air Cleaner

P.15-3

).

AC310442

1

2

3

4

5

6

7

AB

<R.H. drive vehicles>

<L.H. drive vehicles>

Removal steps

1.

Purge hose connection

2.

Vapour hose

3.

Vent connector

4.

Vapour hose

5.

Hose clamp

6.

Canister

7.

Canister bracket