spark MITSUBISHI MONTERO 1991 Service Manual

Removal (SOHC)
1) Drain cooling system. Remove upper and lower intake
manifolds and brackets. See UPPER INTAKE MANIFOLD and LOWER INTAKE
MANIFOLD under REMOVAL & INSTALLATION. Remove spark plug wires. Remove
splash shields.
2) Disconnect O2 sensor. Disconnect exhaust pipe from exhaust
manifold, and support to crossmember using wire. Remove heat shields
and exhaust manifolds. See EXHAUST MANIFOLDS under REMOVAL &
INSTALLATION.
3) Remove distributor (left or rear head). Remove timing bel\
t
outer covers, camshaft sprockets, timing belt and timing belt inner
covers. See TIMING BELT under REMOVAL & INSTALLATION. Remove accessory
bracket bolts from front of cylinder head. Remove rocker cover and
gasket.
4) Using Socket (MD998051), loosen cylinder head bolts in 2-\
3
steps using proper sequence. See Fig. 5. Remove cylinder head and
camshaft assemblies. Note direction of washer installation on head
bolts.
NOTE: Cylinder head bolts must be loosened in 2-3 steps using
proper sequence to prevent cylinder head warpage and
cracking.
Fig. 5: Cylinder Head Bolt Removal & Tightening Sequence
Courtesy of Mitsubishi Motor Sales of America, Inc.
Inspection (SOHC)
Check cylinder head height and warpage at gasket and manifold

surfaces. Resurface head if warpage exceeds specification. See
CYLINDER HEAD (SOHC) table under ENGINE SPECIFICATIONS at end of
article. Replace cylinder head if it is not within specification after
resurfacing.
Installation (SOHC)
1) Ensure mating surfaces are clean and dry. Note
identification mark located on front of head gasket. Identification
marks are: "R" for SOHC, "2DN" for DOHC non-turbocharged and "2DT" for
DOHC turbocharged engine. Install head gasket with identification mark
toward timing belt side of engine and facing upward. Ensure all holes
are aligned.
NOTE: Install head gasket with identification mark toward timing
belt side of engine and facing upward. Ensure all holes
align. Install washers on head bolts with chamfered side
toward bolt head.
2) Install cylinder head and bolts. Ensure washers are
installed on head bolts with chamfered side toward bolt head. Using
proper sequence, tighten bolts to specification in 2-3 steps. See
Fig. 5 . See appropriate TORQUE SPECIFICATIONS table at end of article.
3) Apply sealant to rocker cover sealing surfaces before
installation. See Fig. 6. Ensure rocker cover gasket projections are
aligned with notches in rocker cover. Coat all "O" rings with oil, and
install a new "O" ring on distributor adapter and oil dipstick tube.
4) Coat camshaft area with oil prior to installing
distributor adapter. To complete installation, reverse removal
procedure. Tighten bolts and nuts to specification. See appropriate
TORQUE SPECIFICATIONS table. After engine reaches normal operating
temperature, allow engine to cool, and retighten cylinder head bolts.
Fig. 6: Applying Sealant to Rocker Cover (SOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
Removal (DOHC)
1) Drain cooling system. Remove upper and lower intake
manifolds and brackets. See UPPER INTAKE MANIFOLD and LOWER INTAKE
MANIFOLD under REMOVAL & INSTALLATION.
2) Remove turbocharger(s) (if equipped). See TURBOCHARGER
under REMOVAL & INSTALLATION. Remove heat shields from exhaust
manifolds. Remove exhaust manifolds. See EXHAUST MANIFOLDS under
REMOVAL & INSTALLATION.
3) Remove spark plug wires and ignition coils. Remove rocker
cover and gasket. Remove timing belt and timing belt inner covers. See

Install valve lash adjusters and valve lash adjuster holders (if
removed). See Fig. 18.
2) Apply 3M Sealant (4171) to designated areas of cylinder
head. See Fig. 19. Use care so sealant does not get on camshaft or
camshaft bearing journals. Install rocker arm assembly. Ensure arrow
on bearing cap faces same direction as arrow on cylinder head. See
Fig. 19 . Tighten bearing cap bolts to specification. See appropriate
TORQUE SPECIFICATIONS table at end of article. Remove valve lash
adjuster holders.
3) Coat camshaft oil seal area with oil. Using Seal Installer
(MD998713), install camshaft oil seal. Using Circular Packing
Installer (MD998306), install circular packing to press-in depth of .
02" (.5 mm).
4) Apply Three Bond (1212D) sealant to rocker cover sealing
surfaces before installation. See Fig. 6. Coat new "O" ring with oil,
and install on distributor adapter (if removed).
5) Coat camshaft area with oil before installing distributor
adapter. To complete installation, reverse removal procedure. Tighten
bolts to specification. See appropriate TORQUE SPECIFICATIONS table.
Removal (DOHC)
1) Remove UPPER INTAKE MANIFOLD and LOWER INTAKE MANIFOLD as
necessary. See UPPER INTAKE MANIFOLD and LOWER INTAKE MANIFOLD under
REMOVAL & INSTALLATION. Remove timing belt, camshaft sprockets and
rear timing belt covers. See TIMING BELT under REMOVAL & INSTALLATION.
2) Remove center cover and spark plug wires. Remove PCV and
breather hoses. Remove rocker covers and gaskets. Remove crank angle
sensor adapter. Remove front and rear camshaft bearing caps along with
seals and circular packings.
3) Remove remaining camshaft bearing caps in sequence: No. 2,
No. 4 and No. 3. Remove camshaft, rocker arms and lash adjusters. Mark
component location for reassembly reference.
Inspection (DOHC)
Inspect rocker arm for damaged roller and flaking. Inspect
camshaft for damage. Measure camshaft end play, journal diameter and
lobe height. Replace camshaft if it is not within specification. See
CAMSHAFT (DOHC) table in ENGINE SPECIFICATIONS at end of article.
Installation (DOHC)
1) Coat components with oil. Install lash adjusters and
rocker arms. Bring No. 1 cylinder to TDC. Ensure intake and exhaust
camshafts are installed correctly. Intake camshaft is marked with a
"V" and exhaust camshaft is marked with a "C" on hexagon section.
Position camshaft dowels as shown. See Fig. 21.
NOTE: If cylinder head is off vehicle, support cylinder head at
least .39" (10 mm) above work surface to prevent valve
damage while installing camshaft bearing caps.
Fig. 21: Installing Camshafts & Bearing Caps (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
2) Install camshaft bearing caps in sequence: No. 3, No. 4

\003
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









\









\









\









\









\









\

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









\









\









\









\









\









\

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

pump. If fuel pressure drops slowly, fuel injector is leaking or fuel
pressure regulator valve seat is leaking. Check for faulty fuel
injector or fuel pressure regulator. Repair as required.
11) When fuel pressure test is complete, repeat fuel pressure
release procedure in steps 1) and 2) before disconnecting fuel
pressure gauge. Install new "O" ring at end of high pressure hose.
Check for fuel leaks.
FUEL PUMP TEST TERMINAL LOCATION TABLE









\









\









\









\









\









\









\







Application Wire Color Location
Colt, Colt 200 ......... BLK/WHT .............. Center Of Firewall
Colt Vista ............. BLK/WHT ........ Right Center Of Firewall
Eclipse ................ BLK/WHT .......... Rear Of Battery Compt.
Galant ................. YEL/GRN ........... Left Rear Eng. Compt.
Mirage 1.5L ............ BLK/WHT .............. Center Of Firewall
Mirage 1.6L ............ BLK/BLU .............. Center Of Firewall
Montero .................. WHT .......... Right Center Of Firewall
Pickup ................. BLK/BLU ....... Right Side Of Eng. Compt.
Precis ................... YEL ............. Left Rear Eng. Compt.
Summit ................. BLK/WHT .............. Center Of Firewall
Ram-50 ................. BLK/BLU ....... Right Side Of Eng. Compt.
Stealth, 3000GT ........ BLK/BLU .......... Rear Of Battery Compt.









\









\









\









\









\









\









\







REGULATED FUEL PRESSURE TABLE








\









\









\









\









\









\









\


At Idle At Idle
w/Vacuum w/o Vacuum
Application psi (kg/cm
) psi (kg/cm)
Non-Turbo .................. 38 (2.7) ....... 47-50 (3.3-3.5)
Turbo
Except Eclipse A/T ....... 27 (1.9) ....... 36-38 (2.5-2.7)
Eclipse A/T .............. 33 (2.3) ....... 36-38 (2.9-3.2)









\









\









\









\









\









\









\


Control Relay
Multipurpose relay switches power to vehicle sensors and
actuators including airflow sensor, crank angle sensor, idle speed
control, injectors and fuel pump. When ignition switch is turned to ON
position, ECU energizes coils controlling injectors, airflow sensor
and idle speed control. When ignition switch is turned to START
position, ECU energizes coils (through inhibitor switch on A/T models)\
to supply power to fuel pump. Relay failure will cause a no-start
condition. For testing procedure, see SYSTEM & COMPONENT TESTING
article.
IGNITION CHECKS
SPARK
Check for spark at coil wire (if applicable) and at each
spark plug wire using a high output spark tester. Check spark plug
wire resistance on suspect wires. For wire resistance specification,
see C - SPECIFICATIONS article in the ENGINE PERFORMANCE Section.
CRANK ANGLE SENSOR
For crank angle sensor testing procedure on all models except
Ram-50, Stealth, Eclipse, Laser, Pickup and 3000GT, see TEST NS-5:

Abbreviation Description
AIS ............................ Air Injection System
CBVV ..................... Carburetor Bowl Vent Valve
CE ............................... Check Engine Light
CEC ..................... Computerized Engine Control
EGR ....................... Exhaust Gas Recirculation
EGR-CS ......................... EGR Control Solenoid
EGR-TS ....................... EGR Temperature Sensor
EGR-TV .............................. EGR Thermovalve
EGR-TVS ................... EGR Thermal Vacuum Switch
EGR-VRV .................. EGR Vacuum Regulator Valve
EVAP ........................ Fuel Evaporation System
EVAP-CBVV ........... EVAP Carburetor Bowl Vent Valve
EVAP-CS ....................... EVAP Control Solenoid
EVAP-PV ............................ EVAP Purge Valve
EVAP-TV .......................... EVAP Thermal Valve
EVAP-VC ......................... EVAP Vapor Canister
FBC ............................. Feedback Carburetor
HAC ...................... High Altitude Compensation
HAC-VSV .................. HAC Vacuum Switching Valve
MCV ........................... Mixture Control Valve
O2 .................................... Oxygen Sensor
PAS ............................. Pulse Air Injection
PAS-PAV ......................... PAS Pulse Air Valve
PAS-PAVCS ............ PAS Air Valve Control Solenoid
PAV ................................. Pulse Air Valve
PAV-CSOLV ................ PAV Control Solenoid Valve
PCV .................. Positive Crankcase Ventilation
PFI ............................. Port Fuel Injection
PG-CSOLV ............... Purge Control Solenoid Valve
PG-CV .......................... Purge Control Valve
PG-TV ............................. Purge Thermovalve
SPK ................................... Spark Control
SPK-CC ...................... SPK Computer Controlled
SPK-TVS ................... SPK Thermal Vacuum Switch
TAC ........................ Thermostatic Air Cleaner
TWC .............................. Three-Way Catalyst









\









\









\









\









\









\

remote vacuum regulator. The internal solenoid is normally open, which
causes the vacuum signal to be vented off to the atmosphere when EGR
is not controlled by the Electronic Control Module (ECM). The solenoid\
valve opens and closes the vacuum signal, controlling the amount of
vacuum applied to the diaphragm. See Fig. 12.
The electronic EGR valve contains a voltage regulator, which
converts ECM signal and regulates current to the solenoid. The ECM
controls EGR flow with a pulse width modulated signal based on
airflow, TPS and RPM. This system also contains a pintle position
sensor, which works similarly to a TPS sensor. As EGR flow is
increased, the sensor output increases.
Verify EGR valve is present and not modified or purposely
damaged. Ensure thermal vacuum switches, pressure transducers, speed
switches, etc., (if applicable) are not by-passed or modified. Ensure
electrical connector to EGR valve is not disconnected.
Fig. 12: Cutaway View Of Typical Integrated Electronic EGR Valve
Courtesy of General Motors Corp.
SPARK CONTROLS (SPK)

Spark control systems are designed to ensure the air/fuel
mixture is ignited at the best possible moment to provide optimum
efficiency and power and cleaner emissions.
Ensure vacuum hoses to the distributor, carburetor, spark
delay valves, thermal vacuum switches, etc., are in place and routed
properly. On Computerized Engine Controls (CEC), check for presence of\
required sensors (O2, MAP, CTS, TPS, etc.). Ensure they have not been
tampered with or modified.
Check for visible modification or replacement of the feedback
carburetor, fuel injection unit or injector(s) with a non-feedback
carburetor or fuel injection system. Check for modified emission-
related components unacceptable for use on pollution-controlled
vehicles.
AIR INJECTION SYSTEM (AIS)
Air Pump Injection System (AP)
The air pump is a belt-driven vane type pump, mounted to
engine in combination with other accessories. The air pump itself
consists of the pump housing, an inner air cavity, a rotor and a vane
assembly. As the vanes turn in the housing, filtered air is drawn in
through the intake port and pushed out through the exhaust port. See
Fig. 13 .
Check for missing or disconnected belt, check valve(s),
diverter valve(s), air distribution manifolds, etc. Check air
injection system for proper hose routing.
Fig. 13: Typical Air Pump Injection System
Courtesy of General Motors Corp.
Pulsed Secondary Air Injection (PAIR) System
PAIR eliminates the need for an air pump and most of the
associated hardware. Most systems consists of air delivery pipe(s),
pulse valve(s) and check valve(s). The check valve prevents exhaust
gases from entering the air injection system. See Fig. 14.
Ensure required check valve(s), diverter valve(s), air
distribution manifolds, etc., are present. Check air injection system
for proper hose routing.

than .010" (.25 mm) from tip. Chamfer sharp edge of reground valve
tip. Recheck valve stem installed height.
VALVE STEM OIL SEALS
Valve stem oil seals must be installed on valve stem. See
Fig. 2 . Seals are needed due to pressure differential at the ends of
valve guides. Atmospheric pressure above intake guide, combined with
manifold vacuum below guide, causes oil to be drawn into the cylinder.
Exhaust guides also have pressure differential created by
exhaust gas flowing past the guide, creating a low pressure area. This
low pressure area draws oil into the exhaust system.
Replacement (On Vehicle)
Mark rocker arm or overhead cam components for location.
Remove rocker arm components or overhead cam components. Components
must be installed in original location. Remove spark plugs. Valve stem
oil seals may be replaced by holding valves against seats using air
pressure.
Air pressure must be installed in cylinder using an adapter
for spark plug hole. An adapter can be constructed by welding air hose
connection to spark plug body with porcelain removed.
Install adapter in spark plug hole. Apply a minimum of 140
psi (9.8 kg/cm
) to adapter. Air pressure should hold valve closed. If
air pressure does not hold valve closed, check for damaged or bent
valve. Cylinder head must be removed for service.
Using valve spring compressor, compress valve springs. Remove
valve locks. Carefully release spring compressor. Remove retainer or
rotator and valve spring. Remove valve stem oil seal.
If oversized valves have been installed, oversized oil seals
must be used. Coat valve stem with engine oil. Install protective
sleeve over end of valve stem. Install new oil seal over valve stem
and seat on valve guide. Remove protective sleeve. Install spring
seat, valve spring and retainer or rotator. Compress spring and
install valve locks. Remove spring compressor. Ensure valve locks
are fully seated.
Install rocker arms or overhead cam components. Tighten all
bolts to specification. Adjust valves if required. Remove adapter.
Install spark plugs, valve cover and gasket.
VALVE SPRING INSTALLED HEIGHT
Valve spring installed height should be checked during
reassembly. Measure height from lower edge of valve spring to the
upper edge. DO NOT include valve spring seat or retainer. Distance
must be within specifications. If valves and/or seats have been
ground, a valve spring shim may be required to correct spring height.
See Fig. 12 .
Fig. 12: Measuring Valve Spring Installed Height - Typical
This Graphic For General Information Only

CLUTCH PEDAL POSITION SWITCHES
COLD START INJECTORS
CONNECTORS
COOLANT
COOLANT RECOVERY TANKS
COOLING FAN MOTOR MODULES
COOLING FAN MOTOR RELAYS AND MODULES
COOLING FAN MOTOR RESISTORS
COOLING FAN MOTOR SENSORS AND SWITCHES
COOLING FAN MOTOR SWITCHES
COOLING FAN MOTORS
CRANKSHAFT POSITION SENSORS
DECEL VALVES
DEFLECTORS
DIP STICKS AND TUBES
DIP STICK TUBES
DISTRIBUTOR ADVANCES AND RETARDERS (MECHANICAL AND VACUUM)
DISTRIBUTOR BOOTS AND SHIELDS
DISTRIBUTOR CAPS
DISTRIBUTOR RETARDERS (MECHANICAL AND VACUUM)
DISTRIBUTOR ROTORS
DISTRIBUTOR SHIELDS
DISTRIBUTORS
EARLY FUEL EVAPORATION VALVES (HEAT RISER ASSEMBLIES)
EGR COOLERS
EGR EXHAUST MANIFOLD PASSAGES
EGR INTAKE AND EXHAUST MANIFOLD PASSAGES
EGR PLATES AND COOLERS
ELECTRONIC SPARK CONTROL MODULES
ELECTRONIC TRANSMISSION CONTROL DEVICES
ELECTRONIC TRANSMISSION FEEDBACK DEVICES
ENGINE COOLANT TEMPERATURE SENSORS
ENGINE COOLING SYSTEMS
ENGINE COVERS (OIL PAN, VALVE COVER, TIMING COVER)
ENGINE OIL
ENGINE OIL CANISTERS
ENGINE OIL COOLERS (EXTERNAL)
ENGINE OIL DRAIN PLUGS AND GASKETS
ENGINE OIL FILTERS AND CANISTERS
ENGINE OIL GASKETS
ENGINE OIL PRESSURE GAUGES (MECHANICAL)
EVAPORATIVE EMISSION (EVAP) CANISTER FILTERS
EVAPORATIVE EMISSION (EVAP) CANISTER PURGE DEVICES
EVAPORATIVE EMISSION (EVAP) CANISTERS
EVAPORATIVE EMISSION (EVAP) FEEDBACK DEVICES
EXHAUST GAS RECIRCULATION DEVICES
EXHAUST GAS RECIRCULATION FEEDBACK DEVICES
EXPANSION PLUGS
FAN CONTROL SENSORS
FUEL
FUEL ACCUMULATORS AND DAMPERS
FUEL AND COLD START INJECTORS
FUEL DAMPERS
FUEL DELIVERY CHECK VALVES
FUEL DISTRIBUTORS (BOSCH CIS)
FUEL FILLER NECKS AND RESTRICTORS
FUEL FILTERS
FUEL INJECTORS
FUEL LEVEL SENDERS7
FUEL PRESSURE REGULATORS
FUEL PUMPS (IN-TANK AND EXTERNAL, ELECTRICAL OR MECHANICAL)
FUEL RAILS
FUEL RESTRICTORS