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3.0 L V 6 - V IN S [ B ,C ,S ]
1 991 M it s u bis h i M onte ro
1991 ENGINES
Mitsubishi 3.0L V6
Montero, Pickup, 3000GT
* PLEASE READ THIS FIRST *
NOTE: For engine repair procedures not covered in this article,
see ENGINE OVERHAUL PROCEDURES - GENERAL INFORMATION article
in the GENERAL INFORMATION section.
ENGINE IDENTIFICATION
Engine may be identified by using Vehicle Identification
Number (VIN) stamped on a metal pad, located near lower left corner of\
windshield. The eighth character identifies the engine model.
Engine model number is stamped on front upper edge of
cylinder block (below cylinder head) or on vehicle information plate
on firewall. Engine serial number is stamped near the engine model
number.
ENGINE IDENTIFICATION CODES TABLE
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Application Engine Model Engine Code
3.0L V6 SOHC
Montero ............... 6G72 .................... S
Pickup ................ 6G72 .................... S
3.0L V6 DOHC
3000GT
Non-Turbo ............ 6G72 .................... B
Turbo ................ 6G72 .................... C
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ADJUSTMENTS
VALVE CLEARANCE ADJUSTMENT
NOTE: Hydraulic lash adjusters are set into rocker arms (SOHC) or
cylinder head (DOHC). No adjustment is required.
REMOVAL & INSTALLATION
NOTE: For reassembly reference, label all electrical connectors,
vacuum hoses and fuel lines before removal. Also place
mating marks on engine hood and other major assemblies
before removal.
FUEL PRESSURE RELEASE
Perform these steps to release fuel system pressure:
* Disconnect fuel pump harness connector at fuel tank.
* Start engine. After it stalls, turn ignition switch to OFF
position.
* Disconnect battery (-) terminal, and reconnect fuel pump
harness connector.
FUEL GAUGE
Simple Test
Disconnect fuel sending unit connector wire in luggage
compartment, cargo space, or at tank unit. Connect a 12-volt, 3.4-watt
bulb to harness side of connector, between power terminal and ground
(Yellow and Black wires on Montero). On Pickup and Ram-50 see Fig. 1.
Turn ignition switch to ON position. Ensure test bulb flashes, or
stays on, and fuel gauge needle moves. If bulb or gauge needle does
not function as described, check and repair fuel gauge circuit.
CAUTION: Gauge coils can be damaged if wire is grounded too long.
Perform test as quickly as possible.
Fig. 1: Identifying Fuel Gauge Test Connection (Pickup & Ram-50)
Courtesy of Chrysler Motors.
NOTE: The following test must be completed with instrument panel
cluster removed. Use ohmmeter for all measurements. If
resistance is extremely low, there may be a short in the
coil. If resistance is extremely high, there may be a broken
wire or similar problem in the gauge.
Resistance Test
Remove instrument cluster. See INSTRUMENT CLUSTER under
REMOVAL & INSTALLATION. Measure resistance between appropriate
terminals of instrument cluster or combination gauges. See Fig. 2 or
FUEL SYSTEM PRESSURE RELEASE
WARNING: ALWAYS relieve fuel pressure before disconnecting any fuel
injection-related component. DO NOT allow fuel to contact
engine or electrical components.
1) On Colt and Mirage, remove rear seat cushion. On all
models, disconnect fuel pump harness connector at fuel tank.
2) Start engine. Let engine run until it stops. Turn ignition
off. Disconnect negative battery terminal. Connect fuel pump harness
connector.
FUEL PUMP
Removal & Installation
1) Fuel pump assembly is located inside fuel tank. Release
fuel pressure from system. See FUEL SYSTEM PRESSURE RELEASE. Raise
vehicle on hoist. Drain fuel into suitable container. Disconnect
electrical connectors and fuel hoses at fuel tank.
2) Remove fuel filler hose from fuel tank. Remove nuts
securing fuel tank. Remove fuel tank from vehicle and remove fuel pump
assembly. To install, reverse removal procedure. Tighten nuts to
specification. See TORQUE SPECIFICATION table.
FUEL RAILS & INJECTORS (PFI)
Use a rag to cover fuel hose connection before disconnecting
high pressure fuel hose at fuel rail. Some residual fuel pressure may
still be in system.
Removal (Except Pickup & Ram-50 2.4L)
1) On all models, relieve fuel pressure. See
FUEL SYSTEM PRESSURE RELEASE . Disconnect negative battery cable. On
Montero, Pickup, Ram-50, Stealth and 3000GT 3.0L, disconnect air
intake plenum. On Eclipse, disconnect PCV valve hose.
2) On Colt Vista, disconnect coolant temperature sensor
connector, idle speed control servo connector and brake booster vacuum
hose. On all models, disconnect high pressure fuel hose at fuel rail.
3) Disconnect fuel return hose. Disconnect vacuum hoses. On
Eclipse, Colt and Colt 200, disconnect throttle cable clamp. Remove
center cover. On all models, disconnect injector electrical
connectors. Remove fuel rail bolts and lift fuel rail and injectors
from engine.
Installation
To install, reverse removal procedure. Tighten bolts to
specifications. See TORQUE SPECIFICATIONS table.
Removal (Pickup & Ram-50 2.4L)
1) Relieve fuel pressure. See FUEL SYSTEM PRESSURE RELEASE.
Disconnect negative battery cable. Drain coolant. On all models,
disconnect air intake hose. Disconnect breather hose (if applicable)
and vacuum hoses.
2) Disconnect coolant lines as necessary for clearance.
Disconnect injector electrical connectors. Position all lines, hoses
and electrical connectors out of way. Disconnect throttle and/or
kickdown cables. Remove throttle body assembly and position it out of
the way.
3) Disconnect high pressure fuel hose at fuel rail.
Disconnect fuel return line and vacuum line connection at fuel rail.
Remove fuel rail bolts and lift fuel rail and injectors from engine.
intake hoses and EGR pipe. Disconnect oxygen sensor electrical
connector.
2) Remove oil pipe and EGR valve. Disconnect exhaust fitting
and remove rear heat protector. Remove oil return pipe. Remove
turbocharger assembly. See Fig. 11.
Fig. 11: Removing Rear Turbocharger (Stealth & 3000GT)
Courtesy of Mitsubishi Motor Sales of America.
Inspection
Check turbine and compressor wheels for cracking and other
damage. Make sure turbine and compressor wheels turn smoothly. Check
for oil leakage from turbocharger assembly. Check for proper wastegate
valve operation. See SYSTEM & COMPONENT TESTING article.
Installation
1) To install, reverse removal procedure. Before oil pipe
flare nut (above turbocharger) is installed, pour clean engine oil
into turbocharger. Ensure oil and air hoses are properly installed and
securely clamped.
2) Use new gaskets. Adjust accelerator cable (if necessary).\
Refill engine oil and coolant. Check for oil and coolant leaks.
Tighten all bolts to specification. See TORQUE SPECIFICATIONS table.
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE\
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Applications Ft. Lbs. (N.m)
Fuel Tank Nuts ............................. 15-22 (20-30)