1991 MITSUBISHI MONTERO engine

area. Always wear eye protection when working around air conditioning
systems and R-12. The system's high pressure can cause severe injury
to eyes and skin if a hose were to burst. R-12 evaporates quickly
when exposed to atmosphere, freezing anything it contacts.
2) Use care when handling refrigerant containers. DO NOT drop
or strike containers or expose refrigerant containers to excessive
heat. Containers must never be heated more than 125
F (52C). Never
expose R-12 directly to open flame.
CAUTION: When R-12 is exposed to an open flame, drawn into a running
engine, or detected with a Halide (propane) leak tester,
poisonous phosgene gas is formed. Keep work areas ventilated
and avoid running engines near work area.
USING INDIVIDUAL R-12 CANS
Disposable refrigerant cans (referred to as one pound cans)
have a flat type seal or a screw type seal, and proper can tap must be
used for each type. Be sure sealing gasket on can tap is in good
condition. A proper safety can tap will prevent refrigerant from
flowing back into open can, as tap has a one-way flow control.
NOTE: Recent findings by the EPA indicate that refrigerant is
harmful to the Earth's protective Ozone layer. When
discharging refrigerant avoid allowing refrigerant to enter
the atmosphere. Refrigerant recovery system should be used
when discharging the system.
MULTI-CAN DISPENSING VALVES
A multi-can dispensing valve allows attachment of several
cans of refrigerant, and is a good substitute when a bulk container is
not available. Cans are installed onto each leg of multi-can
dispensing valve in the same manner as the individual cans, and each
leg has its own can tap.
CAN TAP INSTALLATION FLAT TYPE SEAL CANS
On cam-lock or one-piece can taps, first turn the handle
outward to the fully open position. Securely engage locking lugs over
the can flange, and lock them in place by turning cam lock or locking
nut. Screw tap assembly into adapter so sealing gasket is fully seated
against the can top. Turn tap inward to pierce the can and close the
tap. DO NOT open tap until ready to purge the service hose or dispense
refrigerant into the system.
On 2-piece can taps, be certain tap handle is turned fully
inward to the closed position. Check that locking base is turned to
its outer limit. Securely engage locking lugs over the can flange.
Turn entire tap assembly (without disturbing the closed setting)
downward into the locking base to pierce the can. DO NOT open tap
until ready to dispense into system.
SCREW TYPE SEAL CANS
Ensure can tap is fully closed. Screw refrigerant can into
can tap fitting until tight. This will pierce the can. Connect tap to
center hose on manifold gauge set. DO NOT open tap until ready to
dispense R-12 into system.
WARNING: DO NOT open high side hand valve while air conditioning

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D - A D JU STM EN TS

1991 M it s u bis h i M onte ro
1991 ENGINE PERFORMANCE
On-Vehicle Adjustments
Chrysler Motors: Colt, Colt 200, Colt Vista,
Ram-50, Stealth, Summit
Mitsubishi: Eclipse, Galant, Mirage, Montero,
Pickup, 3000GT
ENGINE MECHANICAL
Before performing any on-vehicle adjustments to fuel or
ignition system, ensure engine mechanical condition is okay.
VALVE CLEARANCE
NOTE: All engines except 1.5L use hydraulic valve lifters. Valve
adjustment is only required on 1.5L engines. To check
hydraulic valve lifter operation, see CHECKING HYDRAULIC
VALVE LIFTERS.
MECHANICAL VALVE LIFTERS
CAUTION: DO NOT rotate crankshaft in opposite direction of normal
engine rotation.
1.5L
1) Ensure engine is at normal operating temperature. Remove
all spark plugs and valve cover. Rotate crankshaft to position
cylinder No. 1 on TDC of compression stroke. Adjust intake valves on
cylinders No. 1 and No. 2, and exhaust valves on cylinders No. 1 and
No. 3. See VALVE CLEARANCE ADJUSTMENT table for specification.
2) Rotate crankshaft 360 degrees to position cylinder No. 4
on TDC of compression stroke. Adjust intake valves on cylinders No. 3
and No. 4, and exhaust valves on cylinders No. 2 and No. 4.
VALVE CLEARANCE ADJUSTMENT TABLE









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Cold Hot
Application In. (mm) In. (mm)
Intake ............ .003 (.07) ......... .006 (.15)
Exhaust ........... .007 (.17) ......... .010 (.25)









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CHECKING HYDRAULIC VALVE LIFTERS
Except 1.5L
1) Remove valve cover. Push downward on end of rocker arm
above lash adjuster. If lash adjuster is normal, it will feel hard. If
lash adjuster moves downward easily when pushed, replace adjuster.
2) If lash adjuster feels soft or spongy, oil with air has
probably entered lash adjuster. If this occurs, check engine oil
level. If engine oil level is okay, check oil screen and oil screen
gasket for damage.
3) After repairing cause of air leak, warm engine to
operating temperature. Drive vehicle at low speed for approximately 5
minutes. Turn engine off for a few minutes.
4) Restart engine and drive at low speed for approximately 5

minutes. Repeat this step several times for about one hour. This helps
remove air from engine oil.
IGNITION TIMING
NOTE: Perform all adjustments with engine at normal operating
temperature, cooling fan and accessories off, transmission
in Park or Neutral, and front wheels in straight-ahead
position. Set curb idle speed to specification. See IDLE
SPEED SPECIFICATIONS table under IDLE SPEED & MIXTURE.
IGNITION TIMING
1) Locate ignition timing adjustment connector. See IGNITION
TIMING ADJUSTMENT CONNECTOR LOCATION table. Connect jumper wire
between ignition timing adjustment connector and ground. Check
ignition basic timing.
2) If ignition basic timing is not within specification,
loosen distributor (or crank angle sensor on engines with dual coil
assembly) and rotate to adjust timing if necessary. See IGNITION
TIMING SPECIFICATIONS table. Disconnect jumper wire from ignition
timing adjustment connector.
IGNITION TIMING SPECIFICATIONS TABLE (Degrees BTDC@RPM)









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Application (1) Basic (1) (2) Actual
1.5L
Colt, Colt 200
Mirage & Summit ....... 5@650-850 ........ 10@650-850
1.6L
Mirage ................. 5@650-850 ......... 8@650-850
1.8L
Eclipse ................ 5@600-800 ........ 10@600-800
2.0L
Colt Vista &
Galant (VIN V) ........ 5@600-800 ........ 10@600-800
Eclipse ................ 5@650-850 ......... 8@650-850
Galant
(VIN R) ............... 5@650-850 ......... 8@650-850
(VIN U) ............... 5@650-850 ........ 12@650-850
2.4L
Pickup & Ram-50 ........ 5@650-850 ......... 8@650-850
3.0L
Montero, Pickup, Ram-50
Stealth & 3000GT ...... 5@600-800 ........ 15@600-800
(1) - Transmission in Park or Neutral.
(2) - Actual timing may fluctuate.









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IGNITION TIMING ADJUSTMENT CONNECTOR LOCATION TABLE








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Application (1)(2) Wire Color Locati\
on
Colt, Colt Vista, Colt 200,
Mirage & Summit
1.5L, 1.6L & 2.0L ................ Yellow/Red ............. (3)\
Eclipse
1.8L & 2.0L (Except Turbo) ........ Yellow/Red ............. (4\
)
2.0L Turbo ....................... Yellow/Black ............ (4)\
Galant

2.0L .............................. Yellow/Red ............. (5)\
Montero
3.0L ............................. White/Yellow ............ (4)\
Pickup & Ram-50
2.4L .............................. Black/Blue ............. (6)\
3.0L ............................. White/Yellow ............ (6)\
Stealth (SOHC)
3.0L ............................. White/Yellow ............ (4)\
Stealth & 3000GT (DOHC)
3.0L (Non-Turbo) ................. Black/Green ............. (4\
)
3.0L (Turbo) ..................... White/Yellow ............ (4\
)
(1) - Remove waterproof female connector (if equipped) for access to\
wire.
(2) - Ground connector at wire end for basic timing adjustment.
(3) - On main wiring harness, near center of firewall.
(4) - On main wiring harness, near wiper motor on firewall.
(5) - On main wiring harness, near master cylinder on firewall.
(6) - Between right shock tower and firewall.
(7) - Near front of right shock tower.









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IDLE SPEED & MIXTURE
NOTE: Perform adjustments with engine at normal operating
temperature, cooling fan and accessories off, transmission
in Park or Neutral, and front wheels in straight-ahead
position.
CURB (SLOW) IDLE SPEED
NOTE: Curb idle speed is controlled by Idle Speed Control (ISC)
motor. Adjustment is usually not necessary. For curb idle
speed specifications, see IDLE SPEED SPECIFICATIONS table
under BASIC IDLE SPEED.
1) Check ignition timing and adjust if necessary. Run engine
at 2000-3000 RPM for more than 5 seconds. Allow engine to idle for 2
minutes. Check curb idle speed.
2) If curb idle speed is not within specification, check ISC
system. If ISC system is okay, adjust basic idle speed. See BASIC IDLE
SPEED.
BASIC IDLE SPEED
NOTE: ALWAYS check TPS adjustment after adjusting basic idle
speed. See THROTTLE POSITION SENSOR (TPS).
BASIC IDLE SPEED TEST APPLICATION TABLE









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Application Test
1.5L
Colt, Colt 200,
Mirage & Summit ............. TEST NO. 1
1.6L
Mirage ....................... TEST NO. 2
1.8L
Eclipse ...................... TEST NO. 1
2.0L (VIN V)
Colt Vista & Galant .......... TEST NO. 1
2.0L (VIN R & U)

Eclipse & Galant ............. TEST NO. 2
2.4L
Pickup & Ram-50 .............. TEST NO. 1
3.0L
Montero, Pickup, Ram-50,
Stealth & 3000GT ............ TEST NO. 2









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Test No. 1
1) Loosen throttle cable. Turn ignition on for more than 15
seconds. DO NOT start engine. Turn ignition off. This should fully
retract ISC motor plunger.
2) On 2.0L Galant (VIN V), connect jumper wire between
ignition timing adjustment connector and ground. See IGNITION TIMING
ADJUSTMENT CONNECTOR LOCATION table under IGNITION TIMING.
3) On all models, disconnect harness connector(s) from Idle
Speed Control (ISC) motor. Ensure ISC plunger is in fully retracted
position. Unscrew fixed Speed Adjusting Screw (SAS) until throttle
valve is fully closed. See Fig. 1.
CAUTION: When cleaning throttle body, plug air by-pass hole in
throttle body to prevent solvent from entering passage.
4) Start engine. Check basic idle speed. See IDLE SPEED
SPECIFICATIONS table. If basic idle speed is within specification, go
to step 7). If basic idle speed is not within specification, remove
air intake hose and clean throttle body. Reconnect air intake hose.
Recheck basic idle speed.
5) If basic idle speed is still not within specification
after cleaning throttle body, adjust basic idle speed by turning idle
speed adjusting screw. See Fig. 1. After adjusting basic idle speed,
turn fixed SAS screw clockwise until engine speed begins to increase.
6) Turn fixed SAS screw counterclockwise until engine speed
decreases. Turn fixed SAS screw counterclockwise an additional 1/2
turn from point at which engine speed no longer decreases. Turn off
engine.
7) Adjust throttle cable. Reconnect harness connector(s) at
ISC motor. Start engine. Operate engine for about 5 minutes. Ensure
engine idles within curb idle speed specification. See IDLE SPEED
SPECIFICATIONS table.
8) Turn ignition off. Disconnect negative battery cable for
at least 10 seconds to clear diagnostic trouble code. Reconnect
negative battery cable. Operate engine at idle for about 5 minutes to
ensure engine idles smoothly.
Test No. 2
1) Locate ignition timing adjustment connector. See IGNITION
TIMING ADJUSTMENT CONNECTOR LOCATION table under IGNITION TIMING.
Connect jumper wire between ignition timing adjustment connector and
ground.
2) Locate diagnostic connector under instrument panel.
Connect jumper wire between diagnostic connector terminal No. 10
(White wire) and ground. See Fig. 3. Start engine. Check basic idle
speed. See IDLE SPEED SPECIFICATIONS table. If basic idle speed is
within specification, go to step 9). If basic idle speed is not within
specification, go to step 3).
3) Remove air intake hose. Check throttle body. If throttle
body contains deposits, go to next step. If throttle body is clean,
disconnect jumper wires connected in steps 1) and 2). On all models
except Eclipse, Galant and Mirage, go to step 6). On Eclipse, Galant
and Mirage, go to step 5).
CAUTION: When cleaning throttle body, plug air by-pass hole in

throttle body to prevent solvent from entering passage.
4) Clean throttle body with solvent. Replace air intake hose.
Recheck basic idle speed. If basic idle speed is within specification
after cleaning throttle body, go to step 9). If basic idle speed is
still not within specification after cleaning throttle body,
disconnect jumper wires connected in steps 1) and 2). On all models
except Eclipse, Galant and Mirage, go to step 6). On Eclipse, Galant
and Mirage, go to step 5).
5) Adjust idle position switch and go to step 7). See IDLE
POSITION SWITCH under THROTTLE POSITION SENSOR (TPS).
6) Adjust fixed Speed Adjusting Screw (SAS) and go to next
step. See FIXED SPEED ADJUSTING SCREW under IDLE SPEED & MIXTURE.
7) Reconnect jumper wires as indicated in steps 1) and 2).
Check basic idle speed. If basic idle speed is within specification,
go to step 9). If basic idle speed is not within specification, adjust
by turning idle speed adjusting screw on throttle body. See Fig. 2. Go
to next step.
8) If basic idle speed is within specification after turning
idle speed adjusting screw, go to step 9). If basic idle speed cannot
be adjusted to specification by turning idle speed adjusting screw,
check for leaking fast idle air valve. Replace throttle body if fast
idle air valve leaks.
9) Turn ignition off. Disconnect jumper wires from ignition
timing adjustment connector and diagnostic connector. Operate engine
at idle for about 5 minutes. Ensure engine idles smoothly and within
curb idle specification. See IDLE SPEED SPECIFICATIONS table.
IDLE SPEED SPECIFICATIONS TABLE









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Application Curb Idle Basic Idle
1.5L
Colt, Colt 200,
Mirage & Summit .... 650-850 ...... 700-800
1.6L
Mirage .............. 650-850 ...... 700-800
1.8L
Eclipse ............. 600-800 ...... 650-750
2.0L (VIN V)
Colt Vista .......... 600-800 ...... 650-750
Galant .............. 650-850 ...... 700-800
2.0L (VIN R & U)
Eclipse ............. 650-850 ...... 650-750
Galant .............. 650-850 ...... 700-800
2.4L
Pickup & Ram-50 ..... 650-850 ...... 700-800
3.0L
Montero, Pickup, Ram-50,
Stealth & 3000GT . 600-800 ...... 650-750









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Fig. 1: Idle & Fixed Speed Adj. Screws (1.5L, 1.8L, 2.0L (VIN V)
& 2.4L)

NOTE: Idle mixture is computer controlled on fuel injected engines
and is nonadjustable. CO level specifications are not
available from manufacturer.
THROTTLE POSITION SENSOR (TPS)
TPS ADJUSTMENT
NOTE: Ensure basic idle speed is set to specification before
adjusting TPS. See BASIC IDLE SPEED under IDLE SPEED &
MIXTURE. Perform all adjustments with engine at normal
operating temperature, front wheels in straight-ahead
position, cooling fan and all accessories off, and
transmission in Park or Neutral.
TPS TEST APPLICATION









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Application Test
1.5L
Colt, Colt 200,
Mirage & Summit ............. TEST NO. 1
1.6L
Mirage ....................... TEST NO. 2
1.8L
Eclipse ...................... TEST NO. 3
2.0L (VIN V)
Colt Vista & Galant .......... TEST NO. 1
2.0L (VIN R & U)
Galant ....................... TEST NO. 1
Eclipse ...................... TEST NO. 3
2.4L
Pickup & Ram-50 .............. TEST NO. 1
3.0L
Montero, Pickup & Ram-50 ..... TEST NO. 4
Stealth & 3000GT ............. TEST NO. 5









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Test No. 1
1) Turn ignition on for more than 15 seconds. DO NOT start
engine. Turn ignition off. ISC plunger should be retracted fully.
2) Ensure ISC plunger is in fully retracted position.
Disconnect harness connector(s) from ISC motor. Turn ignition on. DO
NOT start engine.
3) Using digital voltmeter, backprobe terminal No. 19
(Green/White wire) and terminal No. 24 (Black or Green/Black wire) a\
t
Engine Control Unit (ECU) wiring harness connector. Note TPS output
voltage.
4) If output voltage is .48-.52 volt, go to step 6). If
output voltage is not .48-.52 volt, loosen TPS mounting screw(s) and
rotate TPS clockwise, or counterclockwise, until output voltage is
within specification. Tighten TPS mounting screws.
5) Turn ignition off. Reconnect harness connector(s) at ISC
motor. Start engine. Ensure engine idles within curb idle speed
specification.
6) Turn ignition off. Disconnect negative battery cable for
at least 15 seconds to clear diagnostic trouble code. Reconnect
negative battery cable. Operate engine at idle for about 5 minutes to
ensure engine idles smoothly.
Test No. 2
1) Turn ignition on. DO NOT start engine. Loosen throttle

cable. Using digital voltmeter, backprobe terminal No. 19 (Green/White
wire) and terminal No. 24 (Black or Green/Black wire) at Engine
Control Unit (ECU) wiring harness connector. Check TPS output voltage.\
2) If output voltage is .48-.52 volt, go to step 3). If
output voltage is not .48-.52 volt, remove throttle body. Loosen TPS
mounting screws and rotate TPS clockwise, or counterclockwise, until
output voltage is within specification. Tighten TPS mounting screws.
3) Turn ignition off. Disconnect voltmeter from ECU harness
connector. Adjust throttle cable. Disconnect negative battery cable
for at least 10 seconds to clear diagnostic code. Reconnect negative
battery cable. Operate engine at idle for about 5 minutes to ensure
engine idles smoothly.
Test No. 3
1) Turn ignition on for more than 15 seconds. DO NOT start
engine. Turn ignition off. This should fully retract ISC plunger.
2) Ensure ISC plunger is fully retracted. Disconnect TPS
harness connectors. Connect Test Harness (MD998474) between
connectors. Connect digital voltmeter between Red and Blue wires of
test harness.
3) Turn ignition on. DO NOT start engine. TPS voltage should
be .48-.52 volt. If TPS voltage is .48-.52 volt, go to step 4). If TPS
voltage is not .48-.52 volt, loosen TPS mounting screws and rotate TPS
clockwise, or counterclockwise, until correct voltage is obtained.
Tighten TPS mounting screws.
4) Turn ignition off. Disconnect voltmeter and remove test
harness. Reconnect TPS harness connectors. Adjust throttle cable.
Start engine and check idle speed.
5) Turn ignition off. Disconnect negative battery cable for
at least 10 seconds to clear diagnostic trouble code. Reconnect
negative battery cable. Operate engine at idle for about 5 minutes to
ensure engine idles smoothly.
Test No. 4
1) Loosen throttle cable. Disconnect electrical connector
from TPS. Connect digital ohmmeter between Green/White and
Green/Yellow wire terminals of TPS electrical connector (on TPS side
of harness).
2) Insert .026" (.66 mm) feeler gauge between fixed Speed
Adjusting Screw (SAS) and throttle lever. See Fig. 4. Loosen TPS
mounting screws. Rotate TPS fully clockwise. Check for continuity
between Green/White wire and Green/Yellow wire terminals of TPS
electrical connector.
3) Rotate TPS counterclockwise until ohmmeter registers no
continuity. Tighten TPS mounting screws and reconnect TPS electrical
connector.
4) Using digital voltmeter, backprobe terminal No. 19
(Green/White wire) and terminal No. 24 (Black or Green/Black wire) a\
t
Engine Control Unit (ECU) wiring harness connector. Turn ignition on.
DO NOT start engine. Check TPS output voltage.
5) If TPS output voltage is 0.4-1.0 volt, go to step 6). If
TPS output voltage is not 0.4-1.0 volt, check TPS and wiring harness
for damage or malfunction. Replace TPS or repair wiring harness if
necessary and go to next step.
6) Remove feeler gauge. Turn ignition off. Disconnect
voltmeter from ECU connector. Adjust throttle cable. Operate engine at
idle for about 5 minutes to ensure engine idles smoothly and within
specification.
Test No. 5
1) Disconnect electrical connector from TPS. Connect digital
ohmmeter between Yellow/Red wire and Black wire terminals of TPS.
2) Insert .026" (.66 mm) feeler gauge between fixed Speed