1991 MITSUBISHI 3000GT compression ratio

00-22GENERAL - General Data and Specifications
Transaxle
Model No. -Type
Manual transaxle
Automatic transaxle
Fuel system
Fuel supply system3000GT
(Non-Turbo)
F5M33 -5speed manual
F4A33 - 4-speedautomatic
Electronic
control
multi-pointinjection
3000GT SL
(Non-Turbo)
F5M33 -5-speed manual
F4A33 - 4-speedautomatic
Electronic
control
multi-point
injection
3000GT VR-4
(Turbo)W5MGl
-5-speed manual
-
Electronic
control
multi-pointinjectionENGINE SPECIFICATIONS
Items
Type
Number of cylinders
Boremm (in.)
Strokemm (in.)
Piston displacementcm3 (cu.in.)
Compression ratio
Firing orderTRANSAXLE SPECIFICATIONS
FL
Items
Type
Gear ratio
Final reduction ratio1st
2n’d
3rd
4th
5th
Reverse
Transaxle
Transfer
L
6672 Non-Turbo
V60” DOHCFront Transverse
6
91 .I (3.59)
76.0 (2.99)
2,972 (181.4)
10
1-2-3-4-5-6
6672 Turbo
V60” DOHC
Front Transverse
6
91 .I (3.59)
76.0 (2.99)
2,972 (181.4)
8.0
1-2-3-4-5-6
F5M33W5MGlF4A33
5-speed M/T
3.090
1.833
1.217
0.888
0.741
3.166
4.153
-
5-speed MIT
3.071
1.739
1.103
0.823
0.659
3.076
3.972
0.814i
4-speed AlT
2.551
1.488
1 .ooo
0.685
-
2.176
3.958
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GENERAL - Master Troubleshooting
ROUGH IDLE OR ENGINE STALLS
LProbable causeReference page or remedy
Symptom
Rough idle or engine stallsVacuum leaks
l Purge control valve hosel Vacuum hosesl Intake manifoldl Air intake plenuml Throttle bodyl EGR valve
Ignition system problems16-25
Idle speed set too lowCheck idle speed controlsystem
Idle mixture too lean or too rich-
Fuel injection system problems-
Exhaust gas recirculation (EGR) systemproblems17-11
Engine overheats
114-3
Compression too lowIll-15
ENGINE HESITATES OR POOR ACCELERATION
L
Reference pageSymptomProbable cause
Ignition system problem
Vacuum leaksl Purge control valve hosel Vacuum hosesl Intake manifoldl Air intake plenuml Throttle bodyl EGR valve
Air cleaner clogged
Fuel line clogged
Fuel injection system problem
Emission control system problem
l EGR system always on
Engine overheats
Compression too low11-13
Engine hesitates or poor
acceleration
17-3
15-9
-
17-11
14-3
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II-4ENGINE - Specifications
SPECIFICATIONSMllCA--GENERAL SPECIFICATIONS
‘,
‘dItems
Non-Turbo
Turbo
TypeV-type, DOHC
V-type, DOHC
Number of cylinders
6
6
Boremm (in.)
91 .I (3.587)
91 .I (3.587)
Stroke
mm (in.)
76.0 (2.992)
76.0 (2.992)
Piston displacementcc (win.)2,972 (181.4)
2,972 (181.4)
Compression ratio
10.08.0
Firing order
1-2-3-4-5-6
1-2-3-4-5-6
Valve timing
Intake valve
Opens (BTDC)16
16
Closes (ABDC)55”
55”
Exhaust valve
Opens (BBDC)4850”
Closes (ATDC)1517”SERVICE SPECIFICATIONS
MllCE -
Items
Compression pressure
kPa (psi)/rpm
Non-Turbo
Turbo
Compression pressure difference of all
cylinder
kPa (psi)
Manifold vacuum
mmHg (in.Hg.)
Non-Turbo
Turbo
Bas2Tig;ition timing at curb idle speedAct;ir-&yition
timing at curb idle speed
Curb idle speedrpmStandard value
-
-
-
520 (20)
495 (19)
5” f 2”
Approx. 15”700
ZII 100
Limit
min. 980
(139)/250 - 400
min. 810(115)/250-400
max. 100 (14)
d
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11-28ENGINE - Timing Belt
Tlmlng mark01 N009E
A : :y,y;i;,$yi *&:;.~:;>
Exhaust valveside
*
/’*
120"* -1"
(*
6
7.^^^J‘c;Y
1zv w**
Intake valveside
Front bank
* : Approx. 35” o1 N0, og
Rockercoverslde
Exhaust valveside
Front bank
t~mng markOlNOlO
12. INSTALLATION OF TIMING BELT
(1) Align the timing marks on the respective sprockets.
In case of the camshaft sprockets in the front bank,
I~
proceed as follows:@ Install the crankshaft pulley. Shift the timing mark
on the crankshaft sprocket by three teeth to lower
the piston in No. 1 cylinder slightly from the top
dead center on compression stroke.
CautionTurning the camshaft sprocket with the piston
in No. 1 cylinder located at TDC on compression
stroke may cause the valves to interfere with the
piston.@ Make sure that the timing marks on the camshaft
sprockets for intake and exhaust valves are not
within the range A in the illustration at left.
If the timing mark is within range A, turn the
camshaft sprocket to move the timing mark to the
area closest to the range A.
CautionIn range A, the cam lobe on the camshaft lifts
the valve through the rocker arm and the
camshaft sprocket is apt to rotate by reaction
force of the valve spring. Therefore, be careful
not to have the finger pinched between the
sprockets.@ Turn the camshaft sprocket for either the intake or
exhaust valve to locate the timing mark as shown in
\the illustration at left. Then turn the other crankshaft
to locate the timing mark-as shown in the illustration
at left.
CautionIf the intake and exhaust valves of the same
cylinder lift simultaneously, interference with
each other may result. Therefore, turn the intake
valve camshaft sprocket and the exhaust valve
camshaft alternately.@ Turn the camshaft sprocket clockwise to align the
timing marks.
If the camshaft sprocket has been turned excessive-
ly, turn it counterclockwise to align the timing
marks.
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.@ Align the timing mark of the crankshaft sprocket.
NOTEShift the timing mark of the crankshaft sprocket one
teeth in counterclockwise direction to facilitate belt
installation.

SERVICE ADJUSTMENT PROCEDURES
MlBFHSU
BASIC IDLE SPEED ADJUSTMENT
NOTE(1) The basic idle speed has been factory-adjusted with the
speed adjusting screw (SAS) and does not normally require
adjustment.(2) If the adjustment is required, first check that the ignition
plug, injector,
ISC servo, and compression pressure are
normal.
(1) Before starting the inspection and adjustment procedures,set the vehicle in the following conditions:
l
Engine coolant temperature: 80 to 95°C (176 to 205°F)l Lights, electric cooling fan, accessories: OFF
lTransaxle: Neutral (P range on vehicles with automatic
transaxle)l Steering wheel: Straightforward position
(2) When using the multi-use tester, connect it to the diagnosis
connector.
NOTEThe connection of the multi-use tester grounds the
self-
diagnosis/data transmission selector terminal.
(3) When not using the multi-use tester, proceed as follows:
@) Insert a paper clip into the l-pin blue connector as
shown in the illustration. FUEL SYSTEM
- Service Adjustment Procedurks13-31
i
@ Connect a primary-voltage-detecting tachometer to the
paper clip.
NOTEThe
tacho/neter should read l/3 of the actual engine
speed. This means that the actual engine speed is thetachometer reading multiplied by 3.
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FUEL SYSTEM - 0
n-vehicle Inspection of MPI Components
AIR FLOW SENSORAir flow sensor J
III I
\I\Y7FUO941
@ Equipment side
connector
Air flow rate (liters/second)
@ Harness side
connector
I
Control relay
I
Air flow sensor
ECU
’ 7FUO654
Engine control
unit connector
7FUO653
OPERATIONl
The air flow sensor located in the air cleaner converts the engine intake air volume into a pulse signal of
frequency proportional to the air volume and inputs it to the engine control unit, which then computes thefuel injection rate, etc. based on the input signal.
l
The air flow sensor power is supplied from the control relay to the air flow sensor and is grounded in theengine control unit. The air flow sensor generates a pulse signal as it repeatedly opens and closes
between the 5 V voltage supplied from the engine control unit and ground.
TROUBLESHOOTING HINTS
Hint 1 :If the engine stalls occasionally, crank the engine and shake the air flow sensor harness. If the engineHint 2:stalls, poor contact of the air flow sensor connector is suspected.
If the air flow sensor output frequency is other than 0 when the ignition switch is turned on (but notHint 3:starting the engine), faulty air flow sensor or engine control unit is suspected.
If the engine can be run idle even though the air flow sensor output frequency is out of specification,troubles are often found in other than the air flow sensor itself.
[Examples](1) Disturbed air flow in the air flow sensor
(Disconnected air duct, clogged air cleaner element)
(2) Poor combustion in the cylinder
(Faulty ignition plug, ignition coil, injector, incorrect compression pressure, etc.)
(3) Air leaking into the intake manifold through gap of gasket, etc.
(4) Loose EGR valve seatTSB Revision

FUEL SYSTEM - 0n-vehicleInspection of MPI Components
TOP DEAD CENTER SENSOR
Control relay
1d
@ Equipment side
connector
zd
.+$ t5V z” Output characteristic 2r~,
Normal waveformTime6
it07FUO677
Crank angle sensor/\3
Top dead center sensor/\
Engtne control unit
d
7FUO493I
OPERATIONl
The top dead center sensor senses the top dead center on compression stroke of the No. 1, No. 3 and No.
5 cylinders, converts it into a pulse signal and inputs it to the engine control unit, which then computes thefuel injection sequence, etc. based on the input signal.
l
Power to the top dead center sensor is supplied from the control relay and is grounded to the body. The
top dead center sensor generates a pulse signal as it repeatedly connects and disconnects between 5 Vvoltage supplied from the engine control unit and ground.
TROUBLESHOOTING HINTS
Hint 1:If the top dead center sensor does not function correctly, correct sequential injection is not made sothat the engine may stall, run irregularly at idle or fail to accelerate normally.
Hint 2: If the sensor outputs a pulse signal when the ignition switch is turned ON (with the engine not
running), a faulty top dead center sensor or engine control unit is suspected.
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13-102FUEL SYSTEM - On-vehicle Inspection of MPI Components
TROUBLESHOOTING HINTSHint 1: If the engine is hard to start when hot, check fuel pressure and check the injector for leaks.
Hint 2:If the injector does not when the engine that is hard to start is cranked, the following as well as the
Iinjector itself may be responsible.
(1) Faulty power supply circuit to the engine control unit, faulty ground circuit
\-J
-(2) Faulty control relay
Hint 3:(3) Faulty crank angle sensor, top dead center sensor
If there is any cylinder whose idle state remains unchanged when the fuel injection of injectors is cut
one after another during idling, make following checks about such cylinder.
(1) Injector and harness check
(2) Ignition plug and high tension cable check
(3) Compression pressure check
Hint 4: If the injector harness and individual part checks have resulted normal but the injector drive time is
out of specification, the following troubles are suspected.
(1)Poor combustion in the cylinder (faulty ignition plug, ignition coil, compression pressure, etc.)
(2) Loose EGR valve seating
(3) High engine resistance
INSPECTIONUsing Multi-use Tester
FunctionItem No. Data displayCheck conditionCoolant temperatureStandard valueData reading 41
Drive time”’Engine: Cranking0°C (32”F)*zApprox. 17 ms
20°C (68°F)Approx. 46 ms
8O"C(176"F)Approx. 11 ms
Function
Data readingItem No.Data display
41Drive time*3l Engine coolant tem-perature: 80 to 95°C700 rpm (Idle)2.4-3.0 ms
(176 to 205°F)2,000 rpm2.0-2.6
msl Lamps, electric coolingfan, accessory units:When sharp racing isTo increaseAll OFF
madel Transaxle: Neutral
(P range for vehicle
with A/T)l Steering wheel: Neutral
Check conditionEngine stateStandard value ,
.---NOTE“I : The injector drive time refers to when the supply voltage is 11 V and the cranking speed is less than 250 rpm.*2: When coolant temperature is lower than 0°C (32°F). injection ismade by four-cylinders.---simultaneously.
“3: When the vehicle is new [within initial operation of about 500 km (300 miles)], the injector drive time may be about
10% longer.
Function
Actuator testItem No.
Drive content
Check conditionNormal state
01No. 1 injector shut offEngine: Idling afterIdle state to change
02No. 2 injector shut offwarm-up
(Shut off the injectorsfurther (becoming less
in sequence during afterstable or stalling)
03
No. 3 injector shut offengine warm-up, check
04No. 4 injector shut offthe idling condition)
05No. 5 injector shut off
06No. 6 injector shut off
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