1991 MITSUBISHI 3000GT lights

GENERAL - Precautions before Service0045
c
mm (in.)so005
PRECAUTIONS BEFORE SERWCEMOOOAAOSERVICING ELECTRICAL SYSTEM
1. Note the following before proceeding with work on the
electrical system.
Note that the following must never be done:
Unauthorized modifications of any electrical device or
wiring, because such modifications might lead to a vehicle
malfunction, over-capacity or short-circuit that could result
in a fire in the vehicle.
2. When servicing the electrical system, disconnect the
negative cable terminal from the battery.
Caution1. Before connecting or disconnecting the negative
cable, be sure to turn off the ignition switch and the
lighting switch.(If this is not done, there is the possibility of
semiconductor parts being damaged.)
2. After completion of the work steps [when the
battery’s negative (-) terminal is connected], warm
up the engine and allow it to idle for approximately
five minutes under the conditions described below,in order to stabilize the engine control conditions,
and then check to be sure that the idling is
satisfactory.
Engine coolant temperature: 80 - 95°C (176 - 203°F)
Lights, electric fans, accessories: OFF
Transaxle: neutral position(A/T models: “N” or “P”)
Steering wheel: neutral (center) position
VEHICLE WASHING
If high-pressure car-washing equipment or steam car-washing
equipment is used to wash the vehicle, be sure to maintain the
spray nozzle at a distance of at least 300 mm (12 in.) from any
plastic parts and all opening parts (doors, luggage compart-
ment, etc.).
c
TSB Revision

ENGINE - Service Adiustment ProceduresII-13
I_ ianltion tlminaI!H Connector for Igdpstment 6rown)
4tll II -7FUO9371IGNITION TIMING ADJUSTMENTMllFLAF
(1) The vehicle should be prepared as follows before the
inspection and adjustment.
lEngine coolant temperature: 80 - 95°C (176 - 205°F)
l Lights, electric cooling fan and accessories: OFF
l Transaxle: neutral
(P for A/T)l Steering wheel: neutral position
(2) Insert a paper clip to the connector, and connect a
tachometer to the paper clip.
NOTEDo not use the Multi-use tester.
If tested with the Multi-use tester connected to the
diagnosis connector, the ignition timing will not be the basic
timing but be ordinary timing.
(3) Set the timing light.
(4) Start the engine and run at idle.
(5) Check curb idle speed.
Curb idle speed: 700
f 100 rpm
NOTEThe engine speed indicated is a third of actual speed. In
other words, the reading of the tachometer times 3 is actual
speed.
(6) Turn OFF the ignition switch.
(7) Using a jumper wire, ground the ignition timing adjusting
terminal.
NOTEGrounding this terminal sets the engine to the basic ignition
timing.
\(8) Start the engine and run at idle.
(9) Check basic ignition timing.
Basic ignition timing: 5” BTDC
k 2”
(10)lf not within the standard value range, loosen the crank
angle sensor mounting nut and adjust by turning the crank
angle sensor. Turning it to the counterclockwise retards
timing, and to the clockwise advances it.
(1 l)After adjustment, tighten mounting nut taking care not to
move the crank angle sensor.
(12)Turn OFF the ignition switch.
(13)Disconnect the jumper wire connected at step (7).
(14)Start and run the engine at curb idle speed.
1 TSB Revision

11-14ENGINE - Service Adjustment Procedures
(15)Check to be sure that the idling ignition timing is the correct
timing.
Actual ignition timing: Approx. 15” BTDC
NOTE:d
(1) Ignition timing is variable even under normal operation.
(2) And it is automatically advanced at higher altitudes.
CURB IDLE SPEED INSPECTIONMllFMAB
(1) The vehicle should be prepared as follows before the
inspection.
lEngine coolant temperature: 80 - 95°C (176 - 205°F)
l Lights, electric cooling fan and accessories: OFF
l Transaxle: neutral
(P for A/T)l Steering wheel: neutral position
(2) Connect a tachometer. (Refer to P.l l-1 3.)
(3) Set a timing light.
(4) Using a jumper wire, ground the ignition timing adjusting
terminal.
(5) Start the engine and let it idle.
(6) Check whether or not the ignition timing is the standard
value; if not, adjust.
Standard value: 5” BTDC + 2”
NOTECheck the ignition timing with the Multi-use tester not
connected to the diagnosis connector.
(7) Remove the jumper wire from the ignition timing adjusting
terminal.
(8) When using the Multi-use tester, turn OFF the ignition
switch and connect the tester to the diagnosis connector.
(9) Idle the engine for two minutes.
(10)Check the idle speed.
Curb idle speed:
700 + 100 rpm
NOTE(1) The idling speed is automatically regulated by the
idle-speed control system.
(2)’ The engine speed indicated is a third of actual speed. In
other words, the reading of the tachometer times 3 is
actual speed.
(1l)lf not within the standard value range, refer to GROUP 13 -Service Adjustment Procedures.
d
1 TSB RevisionI

11-16ENGINE - Service Adjustment Procedures
MANIFOLD VACUUM INSPECTION
MllFNAR
(1) The vehicle should be repaired as follows before the
inspection.
lEngine coolant temperature: 80 - 95°C (176 - 205°F)‘dl Lights, electric cooling fan, and accessories: OFF
l Transaxle: Neutral
(P for A/T)l Steering wheel: neutral position
(2) Connect a tachometer. (Refer to P.l l-l 3.)
(3) Disconnect the vacuum hose from the nipple for taking off
fuel pressure regulator vacuum from the air intake plenum.
(4) Conncet a three-way joint between the removed vacuum
hose and the nipple and connect a vacuum gauge to the
joint.
(5) Start the engine and check that idle speed is within the
standard value range.
(6) Check the manifold vacuum.
Standard value:
*
Approx. 520 mmHg (20 in.Hg)
Approx. 495 mmHg (19 in.Hg)LASH ADJUSTERS CHECK
Ml 1 FEAFIf an abnormal noise is heard from the lash adjusters, check as
follows.
(1) After warming up the engine, stop it.
(2) While installed to the cylinder head, press the part where
the rocker arm contacts the lash adjuster at the very top. If
the adjuster is normal, the part pressed will feel very hard.
d
(3) If it easily moves all the way downward when pressed,
there is a malfunction of the lash adjuster and it should be
replaced with a new one.
(4) If it feels spongy or elastic, probably oil with air mixed in it
has entered the lash adjuster. Check whether the amount
of oil is too much or is not enough and the cause of air
becoming mixed into the oil is a damaged oil screen or oil
screen gasket.
(5) After repairing the cause of the air leak, warm up the engine
and then drive the vehicle at low speed for a while. Stop the
engine and leave it off for a few minutes; then restart the
engine and drive at low speed. Repeat this procedure
several times during the course of about one hour so as to
remove the air from the oil.
TSB Revision

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.
TSB Revision

FUEL SYSTEM - On-vehicle Inspection of MPI Components13-55
INSPECTIONUsing Multi-use Tester

Function
Data readingtern No. Data display
12Sensor airvolume(frequency)
Check conditionEngine stateStandard value
l Engine coolant tem-
700 rpm (Idle)25-50 Hzperature: 80 to 95°C
(176 to 205°F)2,000 rpm70-IOOHzl Lights and accessories:OFFRacingFrequency increasesl Transaxle: Neutralwith racing(P range for vehiclewith AIT)l Steering wheel: Neutral
NOTEWhen the vehicle is new [within initial operation of about 500 km (300 miles)], the air flow sensor output frequency maybe about 10% higher.

Function
Data listItem No. Data displayCheck conditionsEngine conditionsStandard value
34Reset signall Engine warm up700 rpm (Idle)ON
condition2,000 rpmOFF
L;
FunctionItem No. Data display
Data list37Volumetric
efficiencyCheck conditionEngine stateStandard valuel Engine coolant tem-700 rpm (Idle)20-35%
perature: 80 to 95°C
(176 to 205°F)
l Lights, electric cooling2,000 rpm15-30%
fan and accessory opera-tion: OFFl Transaxle: NeutralRacingFrequency increases
(P range for vehiclewith racingwith &T)
l Steering wheel: Neutral
Using Oscilloscope(1) Run the engine at idle speed.
(2) Connect the probe to the oscilloscope pick-up point as
shown in the circuit diagram, and check the waveform.
Regular waveform
03A0203
TSB Revision

13-156ENGINE CONTROL - Service Adjustment Procedures
SERVICE ADJUSTMENT PROCEDURES
M13FBCKIACCELERATOR CABLE INSPECTION AND
a ’ADJUSTMENT
For models equipped with the cruise control system, refer to
P. 13-l 58.(1) Turn air conditioner and lights OFF.
Inspect and adjust at no load.
(2) Warm engine until stabilized at idle.
(3) Confirm idle speed is at prescribed rpm.
(4) Stop engine (ignition switch OFF).
(5) Confirm there are no sharp bends in accelerator cable.
(6) Check inner cable for correct slack.
(7) If there is too ‘much slack or no slack, adjust play by the
following procedures.@ Turn the ignition switch to the ON position (without
starting the engine) and leave in that condition for
approximately 15 seconds.@Loosen the adjusting bolts on the air intake plenum, and
then secure the outer cable so that the free play of
th,einner cable will be the standard value.
Standard value:
1 - 2 mm (.04 - .08 in.)3-5 mm
(.12-.20 in.)
NOTE
\JIf there is excessive play of the accelerator cable, the
vehicle speed drop (“undershoot”) when climbing a slope
will be large.
If there is no play (excessive tension) of the accelerator
cable, the idling speed will increase.
(8) After adjusting, confirm that throttle valve fully opens and
closes by operating pedal.
(9) Adjust accelerator cable play and confirm throttle lever
stopper touches the fixed SAS.
ACCELERATOR SWITCH INSPECTION AND
A
nADJUSTMENTMlBFlBC
09FO117Make sure that when the accelerator pedal is free, there is
;$ustingcontinuity between the terminals of the accelerator switch and
/that when the pedal is pressed until the indicated pedal stroke
A reaches the standard value, there is no continuity between
the terminals of the switch.
Standard value:Accelerator switch switching point
2 - 6 mm (.079 - .24 in.)If stroke A is out of specification, adjust with adjusting bolt.
TSB Revision
\
‘LJ ~

CRUISE CONTROL SYSTEM - Troubleshooting13-165
I I3Inspection of indicator light circuitI
CRUl
MAIN-!;$ROLIGNITIONSWITCH(IG1)
l-
CRUISE
CONTROL UNIT
Trl
b!XXSS-AK-RI303
DESCRIPTION OF OPERATION1. Cruise control ON (ASC ON) indicator light
Located in the combination meter, it lights as soon as the main switch is set to ON.
2. Cruise control (CRUISE) indicator light
During cruise control operation, transistor
Tr, in the control unit is kept in the ON state to keep the
indicator light on.
TROUBLESHOOTING HINTSECU terminal voltage
TerminalNo.Signal nameCondition
I
Terminal
voltage
I
23
I I
fr;se control (CRUISE) indicatorWhen cruise control is activeSystem voltage
When cruise control is inactiveov
TSB Revision