Mitsubishi 380. Manual — part 353

EMISSION CONTROL

ENGINE AND EMISSION CONTROL

17-80

COMPONENT LOCATION

M1173007400189

POSITIVE CRANKCASE VENTILATION SYSTEM
CHECK

M1173001100232

1. Remove the positive crankcase ventilation (PCV) valve from

the rocker cover.

2. With the engine idling, put your finger on the open end of the

PCV valve, and check for negative pressure (vacuum).

NOTE: At this time, the plunger in the PCV valve should
move back and forth as the open end is covered and uncov-
ered.

3. If negative pressure is not felt, clean or replace the PCV

valve. Inspect the vacuum supply hose and vacuum supply
hose port for restriction or plugged condition.

POSITIVE CRANKCASE VENTILATION VALVE
CHECK

M1173001200228

1. Hold the positive crankcase ventilation (PCV) valve with the

vacuum side down. Insert a thin rod, and using lamp
pressure, depress the end of the PCV valve spring by 5

− 10

mm. Release pressure on the rod to see if the PCV valve
spring will lift the rod to its original position.

2. If the rod returns quickly to its original position, the PCV

valve is OK. If the stick does not return quickly, clean or
replace the PCV valve.

POSITIVE CRANKCASE

VENTILATION VALVE

07TE008A

PCV VALVE

POSITIVE

CRANKCASE

VENTILATION

VALVE

6EM0400

EMISSION CONTROL

ENGINE AND EMISSION CONTROL

17-81

EVAPORATIVE EMISSION CONTROL SYSTEM

GENERAL DESCRIPTION (EVAPORATIVE EMISSION SYSTEM)

M1173005100706

The evaporative emission (EVAP) system prevents
fuel vapors generated in the fuel tank from escaping
into the atmosphere.
Fuel vapors from the fuel tank flow through the vapor
pipe/hose to be stored temporarily in the EVAP can-
ister.
When the vehicle is in operation, fuel vapors stored
in the EVAP canister flow through the EVAP purge
solenoid, purge port and intake manifold plenum 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-ECU brings the EVAP
purge solenoid into the OFF state to shut off the fuel
vapor flow to the intake manifold plenum. This
ensures driveability when the engine is cold or run-
ning under low load and also stabilizes the emission
level.

SYSTEM DIAGRAM

07DB112A

EVAPORATIVE

EMISSION

PURGE

SOLENOID

ON: OPEN

ENGINE

ECU

INTAKE AIR TEMPERATURE

SENSOR

ENGINE COOLANT

TEMPERATURE SENSOR

MASS AIRFLOW SENSOR

MFI

RELAY

EVAPORATIVE EMISSION

CANISTER

FUEL

TANK

B

EMISSION CONTROL

ENGINE AND EMISSION CONTROL

17-82

COMPONENT LOCATION

M1173007500205

PURGE CONTROL SYSTEM CHECK (PURGE FLOW CHECK)

M1173001400620

01DB051A

WHITE MARK

.

SOLENOID VALVE

CHAMBER

07DB115A

THROTTLE BODY

INTAKE MANIFOLD

FROM

AIRCLEANER

TO

COMBUSTION

CHAMBER

OFF

ON

EVAPORATIVE EMISSION

PURGESOLENOID

(ON: OPENED)

PURGE

FLOW

INDICATOR

(MB995061)

PURGE HOSE

EVAPORATIVE EMISSION

CANISTER

CHAMBER

EMISSION CONTROL

ENGINE AND EMISSION CONTROL

17-83

Required Special Tool:
MB995061: Purge Flow Indicator
1. Disconnect the purge hose from the evaporative emission

(EVAP) purge solenoid, and connect special tool MB995061
between the EVAP purge solenoid and the purge hose.

2. Before inspection, set the vehicle in the following conditions:

• Engine coolant temperature: 80 − 95°C (176 − 203°F)

• Lights, electric cooling fan and accessories: OFF

• Transaxle: P range

3. Run the engine at idle for more than four minutes.

4. Check the purge flow volume when engine is revved

suddenly several times.

Standard value: Momentarily 20 cm

3

/s (2.5 SCFH) or

more.

5. If the purge flow volume is less than the standard value,

check it again with the vacuum hose disconnected from the
EVAP canister. If the purge flow volume is less than the
standard value, check the vacuum port and the vacuum
hose for clogging. Also check the EVAP purge solenoid. If
the purge flow volume is at the standard value, replace the
EVAP canister.

EVAPORATIVE EMISSION PURGE SOLENOID
CHECK

M1173001700289

1. Disconnect the vacuum hose (black, black with red paint

mark) from the evaporative emission (EVAP) purge
solenoid.

NOTE: When disconnecting the vacuum hose, always place
an identification mark so that it can be reconnected at its
original position.

2. Disconnect the harness connector.
3. Connect a hand vacuum pump to nipple (A) of the EVAP

purge solenoid (refer to the illustration at left).

4. As described in the chart below, check airtightness by

applying a vacuum with voltage applied directly from the
battery to the EVAP purge solenoid valve and without
applying voltage.

BATTERY POSITIVE
VOLTAGE

NORMAL CONDITION

Applied

Vacuum leaks

Not applied

Vacuum maintained

AK200339