MITSUBISHI ECLIPSE 1991 Service Manual

FUEL SYSTEM - Troubleshooting14-7
Symptom
Engine will not startor start too hard(Cranks OK)
Rough idle or engine
stumbles
Trouble in the MPI systemCheck for output of self-diagnosis
code.Read the code with a voltmeter.Malfunction
of the fuel pump drive control systemCheck the fuel pump drive controlsystem
and the fuel pump.Malfunction
of the ignition timing control systemMalfunction
of the power transistor
Check the ignition timing.
Check the power transistor as a single
unit.
Power is not supplied to the engine control unit.Check the power supply circuit.Malfunction
of the control relayMalfunction
of the injector
Replace.
Check the injector drive circuit.
Check the injector as a single unit.
The fuel pressure is not proper.Check the fuel pressure.
I
Vacuum hose disconnected or damagedRepair or replace.IMalfunction of
the engine control unit) Replace.
Wire breakage or short circuit occurs in theRepair or replace.
harness, or the connector is improperly connected.
Trouble in the MPI systemCheck for output of self-diagnosis
code.Read the code with a voltmeter.Malfunction
of the sensor
l Intake air temperature sensor
Check the sensor-related circuit.
Check the sensor as a single unit
Probable causeRemedy
l Engine coolant temperature sensorl Barometric pressure sensor
l Ignition switchl Idle position switchl Throttle position sensorl No. 1 cylinder TDC sensor, crank angle sensor
<I .8L Engine>l TDC sensor, crank angle sensor<2.0L DOHC Engine>
l Power steering oil pressure switch
l Air conditioner switch
l Inhibitor switch <A/T>l Motor position sensor <1.8L Engine>l Air flow sensor0 Oxygen sensorMalfunction of the engine control system
l
Stepper motor <2.0L DOHC Engine>l Injector0 Power transistor
Check the actuator-related circuit.Check the actuator as a single unit.

14-8FUEL SYSTEM - Troubleshootingiymptom
<ough idle or engine
#table
Probable causeMalfunction
of the vehicle speed reed switch
Remedy
Check the vehicle speed reed switch.
The fuel pressure is not proper.Check the fuel pressure.
Vacuum hose disconnected or damaged.Repair or replace.Malfunction
of the engine control unit.Replace.
Wire breakage or short circuit occurs in theRepair or replace.
harness, or the connector is improperly connected.
.ngine hesrtates oroor accelerationTrouble in the MPI systemCheck for output of self-diagnosiscode.Read the code with a voltmeter.
Malfunction of the sensorl Intake air temperature sensor
l Engine coolant temperature sensor
l Barometric pressure sensorl Ignition switch
l Idle position switchl Throttle position sensor
Check the sensor-related circuit.Check the sensor as a single unit.l
No. 1 cylinder TDC sensor, crank angle sensor<I .8L Engine>
l TDC sensor, crank angle sensor<2.0L DOHC Engine>
l Power steering oil pressure switchl Air conditioner switchl Inhibitor switch <A/T>l Motor position sensor <I .8L Engine>
l Air flow sensor
l Oxygen sensorMalfunction
of the engine control system
l
Stepper motor <2.0L DOHC Engine>
0 Injector0 Power transistor
Check the actuator-related circuit.
Check the actuator as a single unit.Malfunction
of the air conditioner power relayCheck the system, and the compo-
control systemnents if the system is found defective.
The fuel pressure is not proper.Check the fuel pressure.
Vacuum hose disconnected or damaged.Repair or replace.Malfunction
of the engine control unit.Replace.
Wrre breakage or short circuit occurs in theRepair or replace.
harness, or the connector is improperly connected.

FUEL SYSTEM - Troubleshooting14-S
Symptom
Poor fuel mileage,
Probable cause
Trouble In the MPI system
Remedy
Check for output of self-diagnosis
code.Read the code with a voltmeter.Malfunction
of the sensorl Intake air temperature sensorl Engine coolant temperature sensorl Barometric pressure sensorl Ignition switchl Idle position switch
l Throttle position sensorl No. 1 cylinder TDC sensor, crank angle sensor
Check the sensor-related circuit.Check the sensor as a single unit.
<I .8L Engine>l TDC sensor, crank angle sensor<2.0L DOHC Engine>
l Power steering oil pressure switch
l Air conditioner switch
l lnhrbrtor switch <A/T>l Motor
position sensor <I .8L Engine>
l Air flow sensor
0 Oxygen sensor
Malfunction of the engine control system
l Stepper motor <2.0L DOHC Engine>
0 Injector0 Power transistor
Check the actuator-related circurt.Check the actuator as a single unit.
The fuel pressure is not proper.Check the fuel pressure.

CONTROL FUNCTIONS
<1.8L Engine>
NWEEE- -
FunctionAir-fuelIgnitionIdleAir con-FuelPurgeEGRmixture
timingspeedditionercontrol
controlcontrolpower“d”,i2controlcontrol
relaycontrol
Functional elements
control
In-Power supplyXXXXXXX
Put(Ignition switch coupled)
Power supply (battery backup)
XXXXXXXAir flow sensor
XXXX
lgnitron switch ST terminalXXX(start srgnal)Power
steenng oil pressure switchX
Jut- InjectorXlutIdle speed control servoXPower transistor
X
Arr conditioner power relayX
Control relayX
Purge control solenord valveX
EGR control solenoid valveX<California>
NOTE*: <A/T>
FUEL SYSTEM - Troubleshooting

FUEL SYSTEM - Troubleshootina
<2.0LDOHC Engine>
FunctronArr-fuellgnrtronIdleAir con-
FuelFuel
PurgeEGRmixturetimrng
speeddrtronerpump pressureaircontrc
controlcontrol
controlpowerdrivecontrol
control
relaycontrol
Functronal elementscontrol
InPower supplyXXXXXXXXPut(ignrtron switch coupled)
Power supply (battery backup)
Ix Ix Ix lx lx lx lx Ix
Top dead center sensorI xXI
1 Crank angle sensorIxlxIxIxIxI lxlx
Oxygen sensorI x I
Vehrcle speed sensor
Air conditioner switch
XX
XX”XPower steering
011 pressure switchXIDetonation sensor <Turbo>
lgnrtron switch
X
XXX
lgnrtron switch ST terminalXXX
lnhibrtor switch <A/T>XXX”
)ut-InjectorXutResistor <Turbo>X
Idle speed control servoX
Power transistorI 1x1 I I I I I
Arr condrtroner power relay
Control relay
Fuel pressure control valve <Turbo>
Purge control solenord valve
X
X
X
X
EGR control solenoid valve<California>X
NOTE*: <A/T>

FUEL SYSTEM - Troubleshootinn
MPI CIRCUIT1.8L
Engine <M/T>
VSIBLE3ST1REI--
IGNITIONSWITCHtIGl)
c-59
12s
m458
j;WKPUMP
:ONNECTOR
IGNITIONCOIL
ISTOR
CRANK ANGLAND TOP DE!iDCENTER SENSOR
\/---DISTRIBUTOR5ASSEMBLY
'pcuc
n
,L)‘E
;
6
b
E-
5
5
08 C-64/1
tci3j4
I21
------
-.Vr
MPICONTROLRELAY
r
I
h
Lkn
39‘---,
i
lsil12
iz;.
c-65a-66
135-AC-U0514-NC

FUEL SYSTEM - Troubleshooting14-13
3-BW
COMBINATION
CJa
C-69
-1
c
C-6;
SUB FlLINK(
cQ
C-65 6L
7 3
69
10A
6
14
>
18
0
iz
_---.
13
SIBLE
l-47 loB
Q
l1
'Tc?
--I2 c-50
pil!Ezq:
I
1
I
E
.I
; A-22
1
;&&CATED
C-64
'12 C-58
ON+OFF:21OkPa@OPsI)
%iEi33lmOWOFF:
g#~~p384"8l~
21OOkPaC29BPsl)

FUEL SYSTEM - Troubleshootina
MPICONTROLRELAY
k%sEiow
A-36
INMKR AIRAIRnormmcR RRRew
\/\/\/ \/ \/"3"5"4 "6 “13
sc3m -sd
.02 C-64
MPICONTROLUNIT
MOTORW3P;;ONIDLESWITCHBE"&@-j@"T f#nibi
B-03SENSORB-30B-02
=y-Qgg&q/Y[81
j-1
H
EGR;;i;;;ATURE
(VEHICLES FORCALIFORNIA)
B-06 m
KX35-AC-U0614A-NC

FUEL SYSTEM - Troubleshooting14-15
MPICONTROLRELAY
F EGR CONTROLSOLENOIDi VALVEd
'W CLES
”
1 CALIFORNIA)
I :‘, lo-16
xEDI
2
r3
.&
-L
,
8,
P
1
-.--I3
I1.--3
I--
12
al-62
A-47
SELFDIAGNOSISu
,.
1
B-26
@12
OXYGEN= SENSOR
cz1
B-04
Em
IDLE SPEED
CONTROL
ACTUATOR POWER
i;EERING
F'tF=;;RE
B-17 D

FUEL SYSTEM - Troubleshootina
1.8L Engine <A/T>
IGNISWIlIGNISWITJN(IGl)
3-BW
7
7
6
14
1
>
8
l-6'31
;4
i COMBINATION
30
c!
lEfBl
I 2 a C-59,4669@
IGNITION
COIL
7-POWER_ TRANSISTORFCRANK ANGLE
1-63
422 C-66
k8
104 C-64
MPl_-._ -CONTROLUNIT
35AC-U0515-NC