1991 MITSUBISHI ECLIPSE Oxy

14-24FUEL SYSTEM - Troubleshooting
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PURGECONTROLSOLENOIDVALVE
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COMBINATION
METERmn
I-1I
IGNITIONTIMING
ADJUSTMENT
CONNECTOROXYGENSENSORCHECKCONNECTOR FRONT SIDE
REVERSE SIDEOXYGEN
SENSOR
B-26A-60
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C-56
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6
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-

14-58FUEL SYSTEM -MPI System Inspection <1.8L Engine>
MALFUNCTION INDICATOR LIGHTNWQAB
Among the self-diagnosis items, a malfunction indicator light
comes on to notify the driver of the emission control items
when an irregularity is detected.
However, when an irregular signal returns to
notmal ‘and the
engine control unit judges that it has returned to normal, the
malfunction indicator light goes out.
Moreover, when the ignition switch is turned off, the light goes
out. Even if the ignition switch is turned on again, the light doesnot come on until the irregularity is detected.
Here, immediately after the ignition switch is turn on, the
malfunction indicator light is lit for 5 seconds to indicate that
the malfunction indicator light operates normally.
Items indicated by the lightening malfunction light
Engine control unit
Oxygen sensor
Air-flow sensor
Intake air temperature sensor
Throttle position sensor
Motor position sensor
Engine coolant temperature sensor
Crank angle sensor
No. 1 cylinder TDC sensor
Barometric pressure sensor
Ignition timing adjustment signal
Injector
Fuel pump
EGR system Caution
The malfunction indicator light lights up when the ignition
timing adjustment terminal is short-circuited
,‘t’o ground.
Consequently, it lights up ,when the ignition timing
adjustment is grounded when adjusting ignition timing,
but in this case there is no abnormality.
MALFUNCTION INDICATOR LIGHT INSPECTlON
When turning on the ignition switch, check that the light comes
on.
NOTElf the light does not come on, check the harness and light for
breakage.SELF-DIAGNOSIS
Nl4PMFaThe engine control unit monitors the input/output signals
(some signals at all times and the others under specified
conditions) of the engine control unit.

14-60FUEL SYSTEM - MPI Svstem lnwection <1.8L Engine>
7 MPI
diagnosis
LGround
DIAGNOSIS CHART (FAULT TREE)output
preference
orderDiagnosis item
1Engrne control
unit
2 2Oxygen sensor Oxygen sensor
3 3Air flow sensor Air flow sensor
4 4Intake air Intake airtemperature sensor temperature sensor
5 5Throttle position Throttle positionsensor sensor
6 6Motor position Motor positionsensor sensor
INSPECTION PROCEDURE - USING VOLTMETERN14PCAGl
(1) Connect an analogue voltmeter to the self-diagnosis con-,z
nectar.
‘~(2) Turn ignition switch to ON, and indication of engine control
unit memory contents will immediately start. If the system
is in normal condition, pointer of voltmeter indicates normalpattern. If any abnormality is in memory, the pointer of
voltmeter will deflect, indicating abnormal item as de-
scribed in “Diagnosis Chart”.
After recording the abnormal item, check and repair each
part according to the check items in “Diagnosis Chart”.
(3) If the defective parts have been repaired, disconnect the
negative terminal of battery cable for
10 seconds or more
and connect it again to make sure that the abnormal code
has been erased.
N14PRACDiagnosis code
Output signal pattern
:1
12A0104
12A0104
12A0104
12A0104
:JJlJJ--
12A0104
LII
12A0104
No.
-
11Retained
12Retained
14
15MemoryCheck item (Remedy)
-(ll#ace engine control
l Harness and connectorl Fuel, pressurel Injectors
(Replace if defective)
l Intake air leaks0 Oxygen sensor
l Harness and connector
(If harness and connector
are normal, replace airflow sensor assembly.)

14-64FUEL SYSTEM -MPI System Inspection <1.8L Engine>
Idle speed controlservo connector
6FU098t(3) Disconnect the idle speed control servo connector.
(4) Connect DC
6V between terminals @) and @ of the idle
speed control servo connector, and then measure the
resistance between terminals
@ and @ of the motor
position sensor connector when the idle speed control
servo is activated (caused to expand and contract).
Standard value: Smooth increase/decrease in accord-
ance with extension and retraction of
idle speed control servo plunger.
Caution
Apply only a 6V DC or lower voltage. Application of
higher voltage could cause locking of the servo gears.
(5) If there is a deviation from the standard value, or if the
change is not smooth, replace the idle speed control servo
assembly.
OXYGEN SENSORN14QDBAb
INSPECTIONCaution
1. Before checking, warm up the engine until engine
coolant temperature reaches 85 to
95°C (185 to 205°F).2. Use an accurate digital voltmeter.
(1) Disconnect the oxygen sensor connector and connect a
voltmeter to the oxygen sensor connector.
(2) While repeating engine racing, measure the oxygen sensor
output voltage.
EngineOxygen sensor
output voltageRemarks
Race0.6- 1 .OVMake air-fuel mixture
rich by accelerator
operation
NOTEFor removal and installation of the oxygen sensor, refer
toGROUP 11
- Exhaust Manifold.
Oxygen sensor installation torque:
40
-50 Nm (30 - 36 klbs.)
EGR TEMPERATURE SENSOR NIIRCHA~Refer to GROUP 25
- Exhaust Gas Recirculation System.
VEHICLE SPEED SENSORN14QEEBaRefer to GROUP 8
- Meters and Gauges.
AIR CONDITIONER SWITCHRefer to GROUP 8
- Column Switch.
N14QQABa

FUEL SYSTEM - MPI System Inspection <2.0L DOHC Engine>
EGR control solenoid valve
[Calif. only]
Purge control solenoid valve
1
/AF--Y:rIgnition coil, Power transistor
Oxygen sensorPower
steering fluid Dressure switch
Coolant temDerature sensor

14-72FUEL SYSTEM - MPI Svstem InsDection <2.0L DOHC Engine>
MALFUNCTION INDICATOR LIGHTAmong the self-diagnosis items, a malfunction indicator light
comes on to notify the driver of the emission control items
when an irregularity is detected.
However, when an irregular signal returns to normal and the
engine control unit judges that it has returned to normal. the
malfunction indicator light goes out.
Moreover, when the ignition switch is turned off, the light goes
out. Even if the ignition switch is turned on again, the light doesnot come on until the irregularity is detected.
Here, immediately after the ignition switch is turn on, the
malfunction indicator light is lit for 5 seconds to indicate that
the malfunction indicator light operates normally.
I--l
klfunctionindicator light
Items indicated by the lightening malfunction light
Engine control unit
Oxygen sensor
Air flow sensor
Intake air temperature sensor
Throttle positron sensor
Engrne coolant temperature sensor
Crank angle sensor
Top dead center sensor
Barometric pressure sensor
Detonatron sensor
Injector
Fuel pump
EGR
Ignition co11
/
iMALFUNCTION INDICATOR LIGHT INSPECTION
When turning on the ignition switch, check that the light comes
on.
NOTEIf the light does not come on, check the harness and light for
breakage.

FUEL SYSTEM- MPI Svstem InsDection <2.0L DOHC Engine>
MPI
diagnosis
I Ground
INSPECTION PROCEDURE - USING VOLTMETERN14PCAGZ
(1) Connect an analogue voltmeter to the self-diagnosis con-
nector.(2) Turn ignition switch to ON, and indication of engine control
unit memory contents will immediately start. If the system
is in normal condition, pointer of voltmeter indicates normalpattern. If any abnormality is in memory, the pointer of
voltmeter will deflect, indicating abnormal item as de-
scribed in “Diagnosis Chart”.
After recording the abnormal item, check and repair each
part according to the check items in “Diagnosis Chart”.
(3) If the defective parts have been repaired, disconnect the
negative terminal of battery cable for
10 seconds or more
and connect it again to make sure that the abnormal code
has been erased.
DIAGNOSIS CHART (FAULT TREE)NlQPRADoutputDiagnosis codeIreference
Dragnosrs Item- Check item (Remedy)
orderOutput signal patternNo.Memory
1Engine controlunit- - W$$ace engine control: I
12A0104
2Oxygen sensor11Retainedl Harness and connector:-J-l-J-0 Oxygen sensor
o Fuel pressure
0 Injectors(Replace if defective)
12A0104l Intake air leaks
3Air flow sensor
:-rLJL ‘*
Retainedl Harness and connector
(If harness and connector
are normal, replace airflow sensor assembly.)
12A0104
4Intake au
J--lNlL l3
Retarnedl Harness and connectortemperature sensor Hl Intake air temperature
sensor
12A0104
5Throttle postron
:n l4
Retainedl Harness and connector
sensorl Throttle position sensorl Idle position switch
17A0104
6Engine coolant
:nn 2’
Retainedl Harness and connectortemperature sensorl Engine coolant temper-
ature sensor
12A0107

FUEL SYSTEM - MPI System Inspection <2.0L DOHC Engine>
6FUO999
Accelerator pedal
DepressedContinuity .
Non-conductive
(03 fl)
ReleasedIConductive (0 fl)I(4) Replace the idle position switch if faulty.
NOTE
For replacement procedure, refer to the idle position switch(fixed speed adjusting screw) adjustment section
(P.14-
52.).OXYGEN SENSOR
NllQDeJ
INSPECTION(1) Disconnect the oxygen sensor connector.
(2) Check that there is continuity [approx. 12
52 at 20°C (68”F)l
between oxygen sensor connector terminal @ and terminal
GO.(3) If there is no continuity, replace the oxygen sensor.
(4) Warm up the engine until the engine coolant temperature
exceeds
80°C (176°F).(5) Use jumper wires to connect oxygen sensor terminal
@and terminal
@ to the battery @ terminal and 0 terminal.
Caution
Be very careful when connecting the jumper wires
because the oxygen sensor will be damaged if a
mistake is made in the connecting terminals.
(6) Connect a digital voltmeter between terminal
@ and
terminal
0.(7) While repeatedly racing the engine, measure the ‘output
voltage of the oxygen sensor.
When racing
engineWhen the
air/fuel mixture raticINSTALLATION
1. For removal and installation of oxygen sensor, refer to
GROUP 11
- Exhaust Manifold.
2. Oxygen sensor tighten to specified torque.
Specified torque: 40
- 50 Nm (29 - 36 ft.lbs.)