Mitsubishi Lancer Evolution IX. Manual - part 357

EMISSION CONTROL <MPI>

ENGINE AND EMISSION CONTROL

17-7

VACUUM CIRCUIT DIAGRAM

M1173007100586

AK501843

From 

air 

cleaner

To

combustion

chamber

Throttle body

B

B

B

W

R

B

B

AB

Inlet manifold

W

R

B

G

Y

L

Fuel
pressure 
regulator

EGR valve

EGR control 
solenoid valve

Purge control 
solenoid valve

Canister

Vacuum hose colour

B: Black
G: Green
L: Light blue
R: Red
W: White
Y: Yellow

Fuel pressure control
solenoid valve

Air by-pass valve

Check valve

Waste gate actuator

Waste gate
solenoid valve

Air cleaner

Y

B

Y

Brown

VACUUM HOSE CHECK

M1173007300193

1. Using the piping diagram as a guide, check to be 

sure that the vacuum hoses are correctly 
connected.

2. Check the connection condition of the vacuum 

hoses, (removed, loose, etc.) and check to be 
sure that there are no bends or damage.

VACUUM HOSE INSTALLATION

M1173007200141

1. When connecting the vacuum hoses, they should 

be securely inserted onto the nipples.

2. Connect the hoses correctly, using the vacuum 

hose piping diagram as a guide.

EMISSION CONTROL <MPI>

ENGINE AND EMISSION CONTROL

17-8

CRANKCASE EMISSION CONTROL 
SYSTEM

GENERAL INFORMATION (CRANKCASE 
EMISSION CONTROL SYSTEM)

M1173005000691

The crankcase emission control system prevents 
blow-by gases from escaping inside the crankcase 
into the atmosphere.
Fresh air is sent from the air cleaner into the crank-
case through the breather hose.

The air becomes mixed with the blow-by gases 
inside the crankcase.
The blow-by gas inside the crankcase is drawn into 
the inlet manifold through the positive crankcase 
ventilation (PCV) valve.
The PCV valve lifts the plunger according to the inlet 
manifold vacuum so as to regulate the flow of 
blow-by gas properly.
In other words, the blow-by gas flow is regulated dur-
ing low load engine operation to maintain engine sta-
bility, while the flow is increased during high load 
operation to improve the ventilation performance.

SYSTEM DIAGRAM

AK501845 AB

PCV valve

Ventilation hose

Breather hose

COMPONENT LOCATION (CRANKCASE 
EMISSION CONTROL SYSTEM)

M1173007400297

AK304227AB

PCV valve

POSITIVE CRANKCASE VENTILATION 
SYSTEM CHECK

M1173001100373

1. Remove the ventilation hose from the PCV valve.
2. Remove the PCV valve from the rocker cover.
3. Reinstall the PCV valve at the ventilation hose.
4. Start the engine and run at idle.

AK300021

PCV valve

AC

EMISSION CONTROL <MPI>

ENGINE AND EMISSION CONTROL

17-9

5. Place a finger at the opening of the PCV valve 

and check that vacuum of the inlet manifold is felt.
NOTE: At this moment, the plunger in the PCV 
valve moves back and forth.

6. If vacuum is not felt, clean the PCV valve or 

replace it.

POSITIVE CRANKCASE VENTILATION 
(PCV) VALVE CHECK

M1173001200336

AK300022

PCV valve

AC

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)

M1173005100717

The evaporative emission control system prevents 
fuel vapors generated in the fuel tank from escaping 
into the atmosphere.
Fuel vapors from the fuel tank flow through the fuel 
tank pressure control valve and vapor pipe/hose to 
be stored temporarily in the canister.
When driving the vehicle, fuel vapors stored in the 
canister flow through the purge solenoid and purge 
port and go into the inlet manifold to be sent to the 
combustion chamber.
When the engine coolant temperature is low or when 
the inlet 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 vapor flow to 
the inlet manifold.
This does not only insure the driveability when the 
engine is cold or running under low load but also sta-
bilize the emission level.

EMISSION CONTROL <MPI>

ENGINE AND EMISSION CONTROL

17-10

SYSTEM DIAGRAM

AK401830AB

Throttle body

Canister

Check valve

From
fuel
tank

OFF

ON

Purge
control
solenoid
valve

Engine 
control
relay

Battery

Engine-ECU

Air flow sensor

Engine coolant
temperature sensor

Intake air
temperature sensor

Barometric pressure sensor

COMPONENT LOCATION (EVAPORATIVE 
EMISSION CONTROL SYSTEM)

M1173007500302

AK304229AB

Purge control
solenoid valve

PURGE CONTROL SYSTEM CHECK

M1173001400664

AK304230AB

Throttle body

Red stripe

1. Disconnect the vacuum hose (red stripe) from 

throttle body and connect it to a hand vacuum 
pump.

2. Plug the nipple from which the vacuum hose was 

removed.

3. When the engine is cold or hot, apply negative 

pressure of 53 kPa, and check the condition of the 
negative pressure.

When engine is cold 

 

(Engine coolant temperature: 40

°C or less)

Engine condition

Normal condition

At idle

Negative pressure is 
maintained.

3,000 r/min

When engine is hot 

 

(Engine coolant temperature: 80

°C or higher)

Engine condition

Normal condition

At idle

Negative pressure is 
maintained.

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

Negative pressure 
will leak.