engine MITSUBISHI MONTERO 1991 Service Manual

EMISSION SYSTEMS
EXHAUST GAS RECIRCULATION (EGR) CONTROL
Federal (Non-Turbocharged)
To lower oxides of nitrogen (NOx) exhaust emissions, a non-
computer controlled exhaust gas recirculation system is used. EGR
operation is controlled by throttle body ported vacuum. Vacuum is
routed through thermovalve to prevent EGR operation at low engine
temperatures.
Spring pressure holds EGR valve closed during low vacuum
conditions (engine idling or wide open throttle). When vacuum pressure\
increases and overcomes EGR spring pressure, EGR valve is lifted and
allows exhaust gases to flow into intake manifold for combustion.
California & Turbocharged
ECU controls EGR operation by activating EGR control solenoid
valve according to engine load. When engine is cold, ECU signals EGR
control solenoid valve to deactivate EGR.
California models are equipped with an EGR temperature
sensor. When EGR malfunction occurs, EGR temperature decreases and ECU
illuminates CHECK ENGINE (malfunction indicator) light.
EGR Control Solenoid Valve
Denies or allows vacuum supply to EGR valve, based upon ECU
commands.
Thermovalve
Denies or allows vacuum supply to EGR valve based on coolant
temperature.
EVAPORATIVE CONTROL
Fuel evaporation system prevents fuel vapor from entering
atmosphere. System consists of a special fuel tank with vapor
separator tanks (if equipped), vacuum relief filler cap, overfill
limiter (2-way valve), fuel check valve, thermovalve (if equipped),
charcoal canister, purge control valve, purge control solenoid valve
and connecting lines and hoses.
Purge Control Solenoid Valve
When engine is off, fuel vapors are vented into charcoal
canister. When engine is warmed to normal operating temperature and
running above idle, ECU energizes purge control solenoid valve,
allowing vacuum to purge valve.
Canister vapors are then drawn through purge valve into
intake manifold for burning. Purge control solenoid valve remains
closed during idle and engine warm-up to reduce HC and CO emissions.
HIGH ALTITUDE CONTROL (HAC)
This system compensates for variations in altitude. When
atmospheric (barometric) pressure sensor determines vehicle is above
preset altitude, ECU compensates by adjusting air/fuel mixture and
ignition timing. If HAC system is inoperative, there will be an
increase in emissions.
PCV VALVE
Positive Crankcase Ventilation (PCV) valve operates in the
closed crankcase ventilation system. Closed crankcase ventilation

system consists of PCV valve, oil separator, breather and ventilation
hoses.
PCV valve is a one-way check valve, located in valve cover.
When engine is running, manifold vacuum pulls PCV valve open, allowing
crankcase fumes to enter intake manifold. If engine backfires through
intake manifold, PCV valve closes to prevent crankcase combustion.
SELF-DIAGNOSTIC SYSTEM
Self-diagnostic system monitors input and output signals. On
all models, codes can be read using analog voltmeter. On some models,
scan tool can be used to read codes. For additional information, see G
- TESTS W/ CODES article.
CHECK ENGINE Light
Also called Malfunction Indicator Light by manufacturer,
comes on when ignition is turned on. Light remains on for several
seconds after engine has started. If an abnormal input signal occurs,
light comes on and code is stored in memory. If an abnormal input
signal returns to normal, ECU turns light off but code remains stored
in memory until cleared. If ignition is turned on again, light will
not come on until ECU detects malfunction during system operation.
NOTE: ECU diagnostic memory is retained by direct power supply
from the battery. Memory is not erased by turning off
ignition but is erased if battery or ECU is disconnected.

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TR AN SM IS SIO N R EM OVA L & IN STA LLA TIO N - A /T
1991 M it s u bis h i M onte ro
199192 TRANSMISSION SERVICING
Transmission Removal & Installation
Mitsubishi: Eclipse, Galant, Mirage, Montero,
Pickup, Precis, 3000GT
MANUAL
NOTE: For manual transmission/transaxle replacement procedures,
see appropriate article in CLUTCHES.
AUTOMATIC FWD MODELS
REMOVAL
1) Remove battery and battery tray. On 3000GT, remove
undercover(s). On Eclipse turbo, drain and remove intercooler. On all
models, remove air cleaner and case. Raise and support vehicle. Remove
wheels. Disconnect control cables at transaxle. Drain transaxle fluid.
2) On Mirage 1.6L, disconnect tension rod. On all models,
disconnect neutral safety switch connector, oil cooler hoses and
electrical connectors from transaxle. Disconnect speedometer cable and
throttle control cable (if equipped). Remove starter motor.
3) On Galant models with electronically controlled
suspension, remove air compressor and bracket. Disconnect front height
sensor rod at lower control arm.
4) On all models, remove upper transaxle-to-engine bolts.
Remove engine undercover (if equipped). On all models, remove drive
axle shafts. See FWD AXLE SHAFTS article in DRIVE AXLES. Separate
lower control arms from struts for access to axle shafts (if
necessary).
5) Remove front exhaust pipe (if necessary). On Eclipse 4WD,\
Galant 4WD and 3000GT, remove right member and gusset. On 4WD models,
separate transfer assembly from transaxle. Reference mark transfer
assembly-to-drive shaft and remove transfer assembly.
6) On all models, remove transmission inspection (dust)
cover. Place index mark on torque converter and drive plate for
reassembly reference. Remove torque converter-to-drive plate bolts.
Push torque converter away from engine into transaxle.
7) Support transaxle with jack. Remove transaxle mounts
bolts, mounting brackets and remaining transaxle-to-engine bolts.
Slide transaxle assembly to right and lower to remove.
CAUTION: Ensure torque converter is fully seated in transaxle before
installation. Always install new snap rings on inner
constant velocity joints.
INSTALLATION
1) To install, reverse removal procedure. Tighten transaxle-
to-engine bolts and torque converter-to-drive plate bolts to
specification. See TORQUE SPECIFICATIONS table at end of article.
2) Ensure reference marks on torque converter-to-drive plate
and transfer assembly-to-drive shaft align. Tighten mounting bolts
with weight of engine and transaxle on mounts. Refill transaxle fluid
to specified level. Adjust all control cables.
RWD MODELS

REMOVAL
1) Disconnect negative battery cable. Remove front exhaust
pipe. On Montero, remove transfer case shift lever knob, dust boot and
retainer plate or console. Remove transfer case gearshift assembly.
2) On all models, raise and support vehicle. Remove
undercarriage cover and/or skid plate(s). Drain transmission and
transfer case (if applicable). Place reference mark on drive shaft(s)\
and remove. Disconnect all external solenoid and switch connections.
3) Disconnect speedometer cable and control cables at
transmission. Remove starter and bellhousing cover. Place reference
mark on torque converter and drive plate for reassembly reference.
Remove torque converter bolts.
4) Disconnect transmission cooler lines. Remove oil filler
tube. Secure transmission on a jack. Raise transmission slightly to
take weight off mount. Remove crossmember-to-mount bolts and
crossmember.
5) Remove transfer case mounting bracket and mount (if
equipped). Remove transmission-to-engine mounting bolts. Carefully
lower transmission from vehicle.
CAUTION: Ensure torque converter is fully seated in transmission
before installation.
INSTALLATION
1) To install, reverse removal procedure. Tighten
transmission-to-engine bolts and torque converter-to-drive plate bolts
to specification. See TORQUE SPECIFICATIONS table at end of article.
Tighten mount bolts with weight of engine and transmission on mounts.
Ensure reference marks on drive shaft(s) and torque converter-to-drive\
plate align.
2) Apply sealant to transfer case gearshift assembly gasket
before installation. Coat transmission oil filler tube "O" ring with
transmission fluid before installation. Refill transmission fluid to
specified level. Adjust all control cables.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS








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Applications Ft. Lbs. (N.m)
FWD Models
Torque Converter-To-Drive Plate Bolt
Precis ....................................... 53-55 (72-76)
All Others ................................... 34-38 (46-52)
Transaxle-To-Engine Block Bolt
Mirage
8-mm Bolt ............................................ (1)
10-mm Bolt ................................. 22-25 (30-34)
12-mm Bolt ................................. 31-40 (42-54)
Eclipse & Galant
8-mm Bolt ............................................ (1)
10-mm Bolt ................................. 22-25 (30-34)
Precis
8-mm Bolt .................................. 22-25 (30-34)
10-mm Bolt ................................. 31-40 (42-54)
3000GT
Upper Coupling Bolts ............................. 54 (73)
Lower Coupling Bolts ............................. 65 (88)

RWD Models
Torque Converter-To-Drive Plate Bolt
Montero ...................................... 25-30 (34-41)
Pickup ....................................... 33-38 (45-52)
Transmission-To-Engine Block Bolt
Montero
10x40-mm Bolt .............................. 22-30 (30-41)
12x40-mm Bolt .............................. 47-61 (64-83)
12x55-mm Bolt .............................. 58-72 (79-98)
Pickup
10x16-mm Bolt .............................. 22-30 (30-41)
10x50-mm Bolt .............................. 31-40 (42-54)
10x70-mm Bolt .............................. 31-40 (42-54)
(1) - Tighten to 84-108 INCH lbs. (10-12 N.m).









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\003
TR AN SM IS SIO N S ER VIC IN G - A /T

1991 M it s u bis h i M onte ro
1991 TRANSMISSION SERVICING
Automatic Transmission
Mitsubishi: Eclipse, Galant, Mirage,
Montero, Pickup, Precis, 3000GT
IDENTIFICATION
MITSUBISHI AUTOMATIC TRANSMISSION APPLICATIONS








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Model Transmission/Transaxle
Eclipse
1.8 & 2.0L ........................... Model F4A22 Transaxle
2.0L Turbo ........................... Model F4A33 Transaxle
All-Wheel Drive (AWD) ................ Model W4A33 Transaxle
Galant
AWD .................................. Model W4A32 Transaxle
DOHC ................................. Model F4A22 Transaxle
SOHC ........................ Model KM175 or F4A22 Transaxle
Mirage
1.5L ................................. Model F3A21 Transaxle
1.6L ................................. Model F4A21 Transaxle
Montero ............................ Model V4AW2 Transmission
Pickup ............................. Model R4AC1 Transmission
Precis ................................ Model KM176 Transaxle
3000GT ................................ Model F4A33 Transaxle









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LUBRICATION
TRANSAXLE/TRANSMISSION SERVICE INTERVALS
Check fluid level every 12 months or 15,000 miles. Change
fluid and filter every 30,000 miles. If vehicle is operated under
severe condition, change fluid more often. If severe darkening of
fluid and strong odor are noted, bands should also be adjusted (if
equipped).
TRANSFER CASE SERVICE INTERVALS
On 4WD and AWD models, change transfer case fluid every 30,
000 miles.
CHECKING FLUID LEVEL
TRANSAXLE/TRANSMISSION
1) Park vehicle on level area. Ensure oil is at normal
operating temperature, parking brake is engaged, and engine is at
idle. Move gear selector through each position, stopping briefly in
each position.
2) Place gear selector in Neutral, and clean area around
dipstick tube. Ensure fluid level is between lower and upper marks,
but never over upper mark, in HOT range. Add or drain fluid if
necessary.

CAUTION: If severe darkening of fluid and strong odor are noted,
change fluid and filter, and adjust bands.
TRANSFER CASE (3000GT)
Lubricant level should be approximately .5" (13 mm) below
fill hole on side of transfer case.
TRANSFER CASE (ALL OTHERS)
Lubricant level should be to bottom of fill hole on side of
transfer case.
RECOMMENDED FLUID
TRANSAXLE/TRANSMISSION
Use Chrysler Plus/Mitsubishi Plus ATF, Dexron and Dexron-II
ATF.
TRANSFER CASES
Use SAE 75W-85 gear oil with API GL-4 rating or higher.
FLUID CAPACITY
TRANSAXLE/TRANSMISSION REFILL CAPACITIES








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Refill Dry Fill
Application Qts. (L) Qts. (L\
)
Mirage ..................... 4.8 (4.5) ............... 13.0 (12.2\
)
Eclipse
F4A22 .................... 4.2 (4.0) ................. 6.4 (6.1\
)
F4A33 & W4A33 ............ 6.4 (6.1) ................. 8.0 (7.6\
)
Galant
2WD ...................... 4.8 (4.5) ................. 6.4 (6.1\
)
AWD ...................... 4.8 (4.5) ................. 6.9 (6.5\
)
Montero .................... 5.8 (5.5) ................. 7.4 (7.0\
)
Pickup ................... 2.0 (1.9)( 1) ............... 10.2 (9.7)
Precis ..................... 4.8 (4.5) ................. 6.4 (6.1\
)
3000GT ..................... 4.8 (4.5) ................. 7.9 (7.5\
)
( 1) - Idle engine in Neutral, then add fluid to bring level between
notches at "H" mark.









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TRANSFER CASE REFILL CAPACITIES








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Application Pts. (L)
Eclipse & Galant ............................ 1.3 (0.6)
Mirage ............................................ N/A
Montero & Pickup ............................ 4.6 (2.2)
3000GT ........................................ .6 (.3)









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DRAINING & REFILLING
NOTE: Although manufacturer recommends changing only fluid, the
oil filter/screen may also require replacement. If replacing

oil filter/screen, note length and location of all bolts.
TRANSAXLE (EXCEPT MONTERO, PICKUP & RAM-50)
1) Remove drain plug(s), and drain fluid. See Fig. 1. Some
applications may contain a drain plug located in housing below drive
axle shaft, in oil pan. Remove oil pan. Remove oil filter/screen if
necessary.
2) If oil filter/screen is replaced, tighten bolts to
specification. See TORQUE SPECIFICATIONS table at end of article.
Clean oil pan, replace gasket, and install oil pan. Tighten oil pan
bolts and drain plug to specification. See TORQUE SPECIFICATIONS
table. Ensure dipstick hole area is clean, and pour approximately 4.2
qts. (4.0L) of Dexron-II fluid into dipstick hole.
3) Operate engine at idle for 2 minutes. Shift transaxle to
each position, ending in Neutral. Add sufficient fluid to reach lower
mark. After reaching normal operating temperature, fluid should be
between upper and lower marks of HOT range on dipstick.
Fig. 1: Locating Drain Plugs
Courtesy of Mitsubishi Motor Sales of America.
TRANSMISSION (MONTERO & PICKUP)
1) Remove drain plug (if equipped) from transmission pan, an\
d
allow fluid to drain. On models without drain plug, remove oil pan
must to drain fluid. Remove oil filter/screen if necessary.
2) If oil filter/screen is replaced, tighten bolts to
specification. See TORQUE SPECIFICATIONS table at end of article.
Clean oil pan, replace gasket, and install oil pan. Tighten oil pan
bolts and drain plug to specification. See TORQUE SPECIFICATIONS
table. Fill transmission, through filler tube, with 5.3 qts. (5.0L) of\
Dexron-II ATF on Montero, or 2.0 qts. (1.9L) on all others. Start
engine, and allow to idle for 2 minutes.
3) Shift transmission into each position, ending in Neutral.
Check fluid level with engine running at idle, and add sufficient

fluid to bring level to lower mark of dipstick if necessary. Recheck
fluid level after transmission is at normal operating temperature.
TRANSFER CASE
Drain plug is located on bottom of transfer case. Change
drain plug gasket whenever fluid is changed. On 3000GT, lubricant
level should be approximately .5" (13 mm) below fill hole on side of
transfer case. On all others models, lubricant level should be to
bottom of fill hole on side of transfer case.
HYDRAULIC CONTROL PRESSURE ADJUSTMENTS
LINE PRESSURE CHECK (EXCEPT MONTERO & PICKUP)
1) Set parking brake. Place shift lever in Neutral position.
Attach engine tachometer. Remove line pressure port plug located above
front transaxle shaft, forward of governor pressure port plug. On
Precis, line pressure port is located below bell housing, at front of
transaxle oil pan. Using appropriate adapter, attach pressure gauge.
2) Start engine, and bring to operating temperature. With
gear selector in Drive position, bring engine speed to 2500 RPM. Pull
throttle control cable (if equipped) wide open at transaxle side.
3) Line pressure should be 98-100 psi (6.9-7.0 kg/cm
) on
Mirage, or 124-127 psi (8.7-8.9 kg/cm) on all others. If line
pressure is not to specification, proceed to LINE PRESSURE ADJUSTMENT.
LINE PRESSURE ADJUSTMENT (EXCEPT MONTERO & PICKUP)
1) Drain transaxle fluid. Remove oil pan. Disconnect throttle
control cable from throttle cam. Remove oil temperature sensor (if
equipped). Disconnect solenoid connector. On some models, it may be
necessary to push solenoid wire harness connector and grommet into
transaxle case.
2) Remove oil filter screen and plate. Noting location and
length of bolts, remove valve body. DO NOT drop internal parts. Adjust
line pressure by turning regulator valve adjusting screw.
3) Turn adjusting screw counterclockwise to increase pressure
or clockwise to decrease pressure. One complete turn of adjusting
screw changes line pressure as follows.
* 3.7 psi (.26 kg/cm
) on Mirage with F3A21 Transaxle
* 5.4 psi (.39 kg/cm) on Precis
* 54 psi (3.8 kg/cm) on all others
4) After adjustment, reverse removal procedure to install.
Refill transaxle.
LINE PRESSURE (MONTERO)
1) Remove plug from line pressure take-off port located
behind transmission shift control lever. Install Hydraulic Pressure
Meter (MD998330) with Adapter (MD998206).
2) Place vehicle on dynamometer. Apply parking brake and
start engine. With brake applied, place transmission in Drive. Note
pressure at idle. Pressure should be 74-85 psi (5.2-6.0 kg/cm
).
3) Raise engine RPM to stall speed (2100-2400 RPM). Note lin\
e
pressure. Pressure should be 156-185 psi (11.0-13.0 kg/cm
).
4) Shift transmission into Reverse with brake applied. At
idle, pressure should be 112-130 psi (7.9-9.1 kg/cm
). Raise engine
RPM to stall speed (2100-2400 RPM). Note line pressure. Pressure
should be 227-285 psi (16.0-20.0 kg/cm
). If readings are not to

initially, lock nut and adjustment rod may rotate together.
6) Back off outer section 2-2 3/4 turns. Rotate outer section
to right and inner section to left until inner section is free of lock
nut. Tighten lock nut by hand until it contacts piston. Using torque
wrench, tighten lock nut to 18-23 ft. lbs. (25-32 N.m).
7) Remove adapter and kickdown servo wrench. Install new "O"
ring in groove around switch. Install switch and snap ring.
TRANSMISSION THROTTLE CONTROL
MIRAGE
1) On all other models, ensure throttle lever is in curb idle
position. Engine must be at normal operating temperature.
2) On all models, raise cover "B" of throttle cable upward to
expose nipple. See Fig. 3. Loosen lower cable bracket mounting bolt.
Move lower cable bracket until distance between nipple and top of
cover "A" on throttle cable is .02-.06" (.5-1.5 mm).
3) Tighten lower cable bracket mounting bolt to 108-126 INCH
lbs. (12-14 N.m). With throttle lever in wide open throttle position,
pull cable upward to ensure some cable free play exists.
Fig. 3: Adjusting Throttle Cable (Mirage)
Courtesy of Mitsubishi Motor Sales of America.
CAUTION: On Pickup, always adjust throttle control cable
whenever idle is adjusted.