1991 MITSUBISHI 3000GT engine

FUEL SYSTEM - On-vehicle Inspection of Mql Components13439(10)Disconnect the vacuum hose from the fuel pressure
regulator, and then measure the fuel pressure while using a
finger to plug the end of the hose.
Standard value:
330
- 350 kPa (47 - 50 psi) at curb idle
295 - 315 kPa (43 - 45 psi) at curb idle(11
)Check to be sure that the fuel pressure during idling does
not decrease even after the engine is raced a few times.
(12)Use a finger to gently press the fuel return hose while
repeatedly racing the engine, and check to be sure that
there is fuel pressure in the return hose also.
NOTEThere will be no fuel pressure in the return hose if there is
insufficient fuel flow.
(13)lf the fuel pressure measured in steps (9) to (12) deviates
from the standard value range, check for the probable
cause by referring to the table below, and. then make the
appropriate repair.
IConditionProbable cause1 RemedyI
l Fuel pressure is too low.l Fuel pressure drops duringracing.l No fuel pressure in fuel returnhose.
Malfunction of the valve seat withinthe fuel pressure regulator, or fuel
leakage to return, side caused byReplace the fuel filter.
Replace the fuel pressure regulator.
Fuel pump low discharge pressure.Replace the fuel pump.
Fuel pressure is too high.
The valve within the fuel pressureregulator is sticking.Replace the fuel pressure regulator.
Clogging of the fuel return hose and/Clean or replace the hose
and/oror the pipe.pipe.
No change of the fuel pressureDamaged vacuum hose or nippleReplace the vacuum hose, or clean
when the vacuum hose is connected clogging.the nipple.
and when not connected.
Malfunction of the fuel pressure controlChecking the fuel pressure controlsystem system
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13-140FUEL SYSTEM - On-vehicle Inspection of MPI Components
(14)Stop the engine and check for a change of the value
indicated by the fuel pressure gauge. The condition is
normal if there is no decrease of the indicated value within~
two minutes.
,If there is a decrease of the indicated value, monitor the
:d ’speed of the decrease, and, referring to the table below,
determine the cause of the problem and make the
appropriate repair.
Condition
After the engine is stopped, thefuel pressure drops gradually.Probable cause
Injector leakage.
Leakage at the fuel pressure
regulator valve seat.Remedy
Replace the injector.
Replace the fuel pressure regulator.
There is a sudden sharp drop of
the fuel pressure immediately
after the engine is stopped.The check valve (within the fuelpump) is not closed.Replace the fuel pump.
(15)Remove all remaining pressure from inside the fuel pipe.(16)Disconnect the fuel pressure gauge and the special tool
from the delivery pipe.
CautionBecause there will be.a slight amount of remaining
pressure in the fuel pipe line, use rags to cover so thatfuel doesn’t splatter.
(17)Replace the O-ring at the end of the fuel high-pressure hose
with a new one.(I 8)After connecting the fuel high-pressure hose to the delivery
pipe, tighten the installation bolt at the specified torque.
dTightening torque: 5.0 Nm (3.6 ftlbs.)
(19)Check to be sure that there is no fuel leakage.@ Apply battery voltage to the terminal for activation of
the fuel pump so as to activate the fuel pump.@ With fuel pressure applied, check for leakage of the fuel
line.
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FUEL SYSTEM - Throttle Body13-143Pre-removal and Post-installation Operation
l Draining and Supplying of Engine Coolant
(Refer to GROUP 00 -Maintenance Service.) - California>
3
THROTTLE BODY
I
idREMOVAL AND INSTALLATION
MIOSA-0
3\
OlFOOO4
NOTEThe layout of vacuum hoses (No. 3) of the constris for the DOHC (Non Turbo) - Federal.
OlFOO53
I drawing
Removal sl
+*1.Connection of accelerator cable2.Connection of air intake hose3. Connection of vacuum hose
4. Connection of TPS connector
5. Connection of
ISC motor connec6. Connedion of water hose
7. Vacuum pipe assembly
8.ThrottlebodyI)*9.Gasket
:eps
:tor
PrelectionThrottle bodySERVICE POINTS OF INSTALLATIONMlBSDAW9. INSTALLATION OF GASKET
Install the gasket so that the projection is where shown in
the illustration.
CautionPoor idling etc. may result if the gasket is installed
incorrectly.
1. ACCELERATOR CABLE ADJUSTMENTFor information concerning adjustment of the accelerator
cable, refer to
P.13-156.
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13-152FUEL SYSTEM- Fuel Line and Vapor Line
03FOO3
05FOO735 Nm7r; ft
Ihr-k” ._..I_.
@dFlare nut,xSERVICE POINTS OF REMOVAL
MlBKBAQ9. 13. REMOVAL OF EYE BOLT
Remove the eye bolt while holding the fuel filter nut
\securely.
Caution
Cover the hose connection with rags to prevent splash
of fuel that could be caused by some residual pressurein the fuel pipe line.
INSPECTION
MIBKCAJ
lCheck the hoses and pipes for cracks, bend, deformation
and clogging.
l Check the canister for clogging.
l Check the fuel filter for clogging and damage.
SERVICE POINTS OF INSTALLATION
MlSKDAU17.5. INSTALLATION OF FUEL VAPOR HOSE
/ 8. FUEL
RETURN HOSE
(1) If the fuel pipe has a stepped part, connect the fuel
hose to the pipe securely, up to the stepped part, as
shown in the illustration.
Iti(2) If the fuel pipe does not have a stepped part, connect
the fuel hose to the pipe securely, so that it is the
standard value.
Standard value: 25
- 30 mm (1.0 - 1.2 in.)
15. INSTALLATION OF HIGH PRESSURE FUEL HOSEApply engine oil to the hose union.
Insert the hose, being careful not to damage the O-ring, and
tighten securely.
CautionBecause there is high pressure applied between the
fuel pump and the injection mixer, be especially sure
that there is no fuel leakage in this area.
12. INSTALLATION OF FUEL FILTER(1) When installing the fuel filter, first temporarily install the
filter to the filter bracket; then insert the main pipe at
the connector part of the high pressure fuel pipe, and
manually screw in the main pipe’s flare nut.
(2) Holding the fuel filter nut, tighten the fuel main pipe’s
flare nut and eye bolt at the specified torque. Then
tighten the filter to the bracket.
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13-154FUEL SYSTEM - Detonation Sensor
DETONATION SENSORREMOVAL AND INSTALLATION
Pre-removal and Post-installation Operation
l Release and Installation of the Air Intake Plenum
(Refer to GROUP
15-Air Intake Plenum.)
l Removal and Installation of the Intake Manifold
(Refer to GROUP 15
- Intake Manifold.)
l * +*I. Detonation sensor
20-25NmSERVICE POINT OF REMOVAL
1. REMOVAL OF DETONATION SENSOR
SERVICE POINT OF INSTALLATION
1. INSTALLATION OF DETONATION SENSOR
When the detonation sensor is installed, be sure to tighten
Idit precisely to the specified torque as its installation affects
the engine control.
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ENGINE CONTROL - Specifications / Troubleshooting13-155
ENGINE CONTROL
i; SPECIFICATIONSSERVICE SPECIFICATIONS
M13CEB
IItems
Standard value
Accelerator cable playmm (in.)


Accelerator switch switching pointmm (in.)
TROUBLESHOOTING
Specifications
1
- 2 (.04 - .08)
3-5(.12-.20)
2 - 6 (08 - .24)ACCELERATOR CABLE AND ACCELERATOR PEDAL
MlSEGAC
ISymptomProbable causeRemedyI
Throttle valve will notfully open or closeMisadjusted accelerator cable
Misadjusted automatic speed-control cable
Broken return spring
Throttle lever malfunction
Adjust
Adjust
Replace
Replace
Accelerator pedaloperation not smooth(over acceleration)
Accelerator pedal wrongly tightened
Misinstalled accelerator cable
Accelerator cable requires lubricationRepair
Repair
Lubricate or replace
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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.
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ENGINE CONTROL - Engine Control13-157
ENGINE CONTROLREMOVAL AND INSTALLATION
L’
/
ii5Nm
4
ftlbs.1
/
Removal steps
I. Adjusting bolt2. Connection of throttle body side inner cable
3. Bushing
4. Accelerator cable
5. Accelerator
oedal6. Spring ’7. Connection of accelerator switch connector8. Accelerator arm bracket9.Split pin10.Accelerator arm11.Return spring12. Accelerator switch 13. Accelerator arm stopper14.Bolt 15.StopperMl30A-
-Post-installation Operation
l Accelerator Cable Adjustment
(Refer to P. 13-156.)l Accelerator Switch Adjustment 07A0031INSPECTION
MlBOCAJl Check the inner and outer cable for damage.
l Check the cable for smooth movement.
l Check the accelerator arm for bending.
l Check the return spring for deterioration.
l Check the connection of bushing to end metal fitting.
l Check the accelerator pedal switch for correct ON-OFF
switching.

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