1991 MITSUBISHI 3000GT Service Manual

17-1
EMISSIONCONTROL
.~
CATALYTIC CONVERTER............................:...Inspection
............................................................Removal and Installation
................................
CONTENTSM17.U. -
CRANKCASE EMISSION CONTROL
SYSTEM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ComponentsLocation
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Crankcase Ventilation System Inspection
._..Positive Crankcase Ventilation Valve
. . . . . . . . . . . .
EVAPORATIVE EMISSION CONTROL
SYSTEM................................................................Air Conditioner Switch
....................................Air Flow Sensor, Engine Coolant
Temperature Sensor and Intake Air
Temperature Sensor
........................................Canister
............................................................Components Location
....................................
FuelFiller CapInspection................................OverfillLimiter (Two-way Valve)
....................Purge Control Solenoid Valve
........................Purge Control System Inspection
....................................................Purge Control System Inspection

............................................................Purge Control Valve
........................
PurgePort VacuumCheck................................14
14
14
6
10
10
10
6
10
10
9
7
8
9
9EXHAUST GAS RECIRCULATION
(EGR)
SYSTEM. . . . . ..____._.._........__........_____.........................Air-FuelRatio Control (MPI) System. . . . . . . .
Components Location
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .EGR Control Solenoid Valve
- Non Turbo, Turbo>. . . . . . . . . . . . . . . . . . . .EGR System Inspection
- Non Turbo, Turbo>. . . . . . . . . . . . . . . . . . . .EGR Temperature Sensor
. . . . . . . .EGR Valve - Non Turbo, Turbo>
EGR Valve Control Vacuum Check
- Non Turbo, Turbo>. . . . . . . . . . . . . . . . . . . .
SPECIFICATIONS................................................General Specifications
....................................Service Specifications
....................................
TROUBLESHOOTING. . . . . . . . . . . . . . . . . ..______...............
VACUUM HOSES................................................Inspection
............................................................Installation
........................................................VacuumHosesRouting
....................................
11
14
11
13
12
13
13
12
2
2
22

17-2EMISSION CONTROL - Specifications / Troubleshooting
SPECIFICATIONS
GENERAL SPECIFICATIONSMl’ICA- -\
Items
Crankcase emission control systemSpecifications
Closed type with positive crankcase ventilationvalve
Evaporative emission control systemCanister storage type
Canister
Charcoal type
Purge control solenoid valve
ON/OFF solenoid valve
Exhaust emission control system
Exhaust gas recirculation system
EGR valveVacuum-activated diaphragm type
EGR temperature sensor Thermistor type
EGR control solenoid valve - Non Turbo, Turbo>Duty cycle solenoid valve
Catalytic converter
Monolith type
Location
Under floor
Turbocharger outlet (front bank and rear bank,)
and under floor
SERVICE SPECIFICATIONSMl7CB-.
ItemsSpecifications
Purge control solenoid valve coil resistance
036 - 44 [at 20°C (68”F)I\
EGR temperature sensor resistancekfl60 - 83 [at 50°C (I 22”F)]
11 - 14 [at 100°C (212”F)l
EGR control solenoid valve coil resistance1236 - 44 [at 20°C (68”F)lI
TROUBLESHOOTING
Symptom
Engine will not start
or hard to start
Rough idle or engine
stalls
Probable cause
Vacuum hose disconnected or damaged
The EGR valve is not closed
Malfunction of the purge control solenoid valve
The EGR valve is not closed
Vacuum hose disconnected or damaged
Malfunction of the positive crankcase ventilationvalveRemedy
Repair or replace
Repair or replace
Repair or replace
Repair or replace
Repair or replace
Replace
Malfunction of the purge control systemCheck the system; if there is a
problem, check its component parts
Engine hesitates or3oor acceleration
Zxcessive oil:onsumptron
Malfunction of the exhaust gas recirculation
system
Positive crankcase ventilation line cloggedCheck the system; if there is a
problem, check its component parts
Check positive crankcase
ventila-tion system
Ioor fuel mileageMalfunction of the exhaust gas recirculation
systemTSB RevisionCheck the system; if there is a
problem, check its component parts
d

EMISSION CONTROL - Vacuum Hoses
VACUUM 1-10sEs
lVACUUM HOSES ROUTING
L//
17-3M17JA-
-
I’
Li
Fuel pressureregulator
Vehicle front
id
L: Light blueR: RedB: Black
7EM0131
EGR controlsolenoid valve
r-c,cud valve/
Canister
/Fuel pressureregulator
v
Vehicle frontG: GreenY: Yellow
L: Light blueR: RedB: Black
TSB Revision
7EM0132I
1

17-4EMISSION CONTROL - Vacuum Hoses
Fuel pressure control
solenoid valveEGR controlWaste gate control
solenoid valve
solenoid valve
/\,i
aste gate actuator
G: GreenY: Yellow
L: Light blueR: RedB: BlackW:White
Purge controlsolenoid valve
Bypass valve
/Fuel pressure regulator
Purge control valve
Waste gate actuator
TLrbocharger7EM0133
INSPECTIONM17JCAF +’
(1) Referring to the VACUUM HOSES ROUTING, confirm that
the vacuum hoses are properly connected.
(2) Check the hoses for irregularities (disconnection, loose-
ness, etc.) and confirm that there is no breakage or
damage.
INSTALLATIONM17JDAF(1) When connecting a hose, firmly press it onto the nipple.
(2) Referring to the VACUUM HOSES ROUTING, connect the
hoses correctly.
TSB Revision

EMISSION CONTROL - Crankcase Emission Control System17-5
CRANKCASE EMISSION CONTROL SYSTEM
COMPONENTS LOCATIONJ
Ir--‘-l7FU1002
Name
Positive crankcase ventilation valveSymbolA
i{
ventilation valve\”
------rLYJ7EM0134M17KA--
CRANKCASE VENTILATION SYSTEM INSPEC-
TIONM171ABG(1) After disconnecting the ventilation hose from the positive
crankcase ventilation valve, disconnect the positive crank-
case ventilation valve from the rocker cover, and reconnect
the positive crankcase ventilation valve to the ventilation
hose.
(2) Idle engine, put finger on the opening end of the positive
crankcase ventilation valve, and check that the negative
pressure of the intake manifold is felt with finger.
NOTEAt this time, the plunger in the positive crankcase ventila-
tion valve moves back and forth.
(3) If negative pressure is not felt, clean or replace the positive
crankcase ventilation valve.
POSITIVE CRANKCASE VENTILATION VALVEMl7lACC
INSPECTION
(1) Remove the positive crankcase ventilation valve.
(2) Insert a thin stick into the positive crankcase ventilation
valve from the threaded side to check that the plunger
moves.
(3) If the plunger does not move, the positive crankcase
ventilation valve is clogged. Clean it or replace.
INSTALLATIONInstall the positive crankcase ventilation valve and tighten to
specified torque.
Specified tightening torque:
10 Nm (7.2 ft.lbs.1TSB Revision

17-6EMISSION CONTROL - Evaporative Emission Control System
EVAPORATIVE EMISSION CONTROL SYSTEM
COMPONENTS LOCATION
-\-\
TUW-\pJJ
7FIIl
NameSymbol
Canister
Purge control solenoid valveB
A
1 Purge control valve I c I
M17LA- -
ITSB RevisionI
Ldi ’
LI

EMISSION CONTROL - Evaporative Emission Control System17-7
PURGE CONTROL SYSTEM INSPECTION M17lBBP
Barometric pressure sensor
Engine control unit
7EM0161I-----I
\7EM0140t
(1) Disconnect the vacuum hose (red stripes) from the throttle
body,and connect it to a hand vacuum pump.
(2) Plug the nipple from which the vacuum hose is discon-
nected.
(3) Under the engine conditions shown below, check by
applying vacuum from a hand vacuum pump.
When engine is cold
-engine coolant temperature:
60°C (140°F) or less
When engine is hot
-engine coolant temperature:
70°C (158°F) or higher
Engine operatingcondttionApplying vacuumResult
ldllng375 mmHg(14.8 In.Hg)Vacuum is maintalned
I
after staitingengineNOTEThe vacuum will leak con-tenuously if the altitudeis 2,200 m (7.200 ft.) or
higher, or the intake airtemperature is 50°C(I 22°F) or higher.TSB Revision

17-8EMISSION CONTROL - Evaporative Emission Control System
PURGE CONTROL SYSTEM INSPECTION M17IBBQ
Canister
Purge control
valve\
PI IrnQ rnntrnlI.1 I
kXffo~~~~r~~ ’ I I-J
relay
Barometric pressure sensor
Intake air temperature sensor
Engine coolant temperature sensor
II1 I IAir flow sensor
Engine control unit
6EM0215(1) Disconnect the purge air hose from the air intake hose, and
plug the air intake hose. Then, connect the hand vacuum
pump to the purge air hose.
(2) Under the engine conditions shown below, check by
applying vacuum from a hand vacuum pump.
When engine is cold
-engine coolant temperature:
60°C (140°F) or less
Engine operating
conditionApplying vacuumResult
Idling
375 mmHgVacuum is maintained
3,000 rpm(14.8 in.Hg)When engine is hot
-engine coolant temperature:
70°C (158°F) or higher
Engine operating
condition
Idling
3,000 rpm within
three minutes after
starting engine
3,000 rpm after
three minutes
have elapsedafter startingengine
Applying vacuum
375
mmHg(14.8 in.Hg)
Try applyingvacuum
375
mmHg(14.8 in.Hg)
Result
Vacuum is marntained
Vacuum leaks
Vacuum WIII be main-tained momentarily, after
which it will leak.
NOTEThe vacuum WIII leak con-
tinuously if the altitude
is 2,200 m
(7,200 ft.) orhrgher. or the Intake arrtemperature is 50°C(122°F) or higher.
1 TSB Revision