1991 MITSUBISHI ECLIPSE engine

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 Svstem InsDection <2.0L DOHC Engine>
outputDiagnosis codeIreferenceDragnosrs ItemCheck item (Remedy)orderOutput signal patternNo.Memory
7Crank angle sensor
:nn **
Retainedl Harness and connector
(If harness and connector
are normal, replace crank
angle sensor assembly.)
12A0107
8Top dead center
:- 23
Retainedl Harness and connectorsensor (No.1 and(If harness and connector
No. 4 cylinder)are normal, replace crank
angle sensor assembly.)
12A0107
9Vehicle speed sensor24Retainedl Harness and connector
(reed swatch)H
I u I nlvln
l Vehicle speed sensor
(reed switch)
L12A0107
10Barometnc pressure25Retainedl Harness and connector
sensorH(If harness and connector
are normal, replace
LULllnMllbarometric pressure
12A0107sensor assembly.)
11Detonation sensorRetainedl Harness and connector
:m 31
l Detonation sensor
12R0468
12Injector
:m 41
Retainedl Harness and connector0 Injector coil resistance
12A0105
13Fuel pump42Retainedl Harness and connectorH
UUUI nn
0 Control relay
L12A0105
14EGR 43Retainedl Harness and connector
Hl EGR temperature sensor
u u u I nnn
l EGRvalvel EGR valve control sole-Lnoid valve
12A0105l EGR valve control vacuum
15Ignition coil44Retainedl Harness and connectorH
UUUL-llMlL
0 Ignition coil0 Power transistor
L12A0105
16Normal state---H
L
12A0104
NOTEReplace the engine control unit if a malfunction code is output although the inspection reveals that there is no problem with the check
items.

14-76FUEL SYSTEM - MPI Svstem InsDection <2.0L DOHC Enaine>

Air flow sensorsrde connector
6FUO622
6FUO623
16Rl251
INTAKE AIR TEMPERATURE SENSOR
INSPECTION
Nl4OHAB
(1) Disconnect the air flow sensor connectors.
(2) Measure resistance between terminals
@ and @I Turbo>
(3) Measure resistance between terminals @and @I
Temperature “C (“F)Resistance kR
0 (32)6.0
20
(68)2.7
80 (176)
0.4(4) Measure resistance while heating the sensor using a hair
drier.
Temperature “C (“F)
Higher
Resistance k0
Smaller(5) If the value deviates from the standard value or the
resistance remains unchanged, replace the air flow sensor
assembly.
ENGINE COOLANT TEMPERATURE SENSOR
NlMABEl
INSPECTION
(1) Remove engine coolant temperature sensor from the
intake manifold.
(2) With temperature sensing portion of engine coolant
temperature sensor immersed in hot water, check resist-
ance.
Temperature
“C (“F)
0 (32)
Resistance kfl
5.9
20 (68)2.5
40 (I 04)2.7
80
(I 76)0.3
(3) If the resistance deviates from the standard value greatly,
replace the sensor.

FUEL SYSTEM - MPI Svstem InsDection <2.0L DOHC Engine>14-77INSTALLATION
(1) Apply specified sealant to threaded portion and tighten to
specified torque.
Specified sealant: MOPAR Part No.4318034 or
equivalent
Specified torque: 20
- 40 Nm (15 - 29 ft.lbs.1(2) Fasten harness connectors securely.
THROTTLE POSITION SENSOR
INSPECTION
N14QBBKl(1) Disconnect the throttle position sensor connector.
(2) Measure resistance between terminal
@I (sensor ground)
and terminal
@ (sensor power).
Standard value: 3.5
- 6.5 kR(3) Connect a pointer type ohmmeter between terminal
@I(sensor ground) and terminal
@ (sensor output).
(4) Operate the throttle valve slowly from the idle position to
the full open position and check that the resistance changessmoothly in proportion with the throttle valve opening
angle.
6FU1244(5) If the resistance is out of specification, or fails to change
smoothly, replace the throttle position sensor.
Throttle position sensor installation torque:
1.5
- 2.5 Nm (1.1 - 1.8 ft.lbs.)
J II\/ hFU1419IDLE POSITION SWITCH
INSPECTION
N14QKAEa(1) Keeping the acceleration pedal released, check that the
throttle valve lever or the idle position switch is pushed.
NOTEIf it is not pushed, adjust the idle position switch (fixed
speed adjusting screw). (Refer to
P.14-52.)(2) Disconnect the idle position switch connector.
(3) Check the continuity between terminal
@) to the ground.

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.)

FUEL SYSTEM - MPI System Inspection <2.0L QOHC Engine>14-79EGR TEMPERATURE SENSOR
N14RCHAaRefer to GROUP 25
- Exhaust Gas Recirculation System.
VEHICLE SPEED SENSOR
Refer to GROUP 8
- Meters and Gauges.
N140EBBaAIR CONDITIONER SWITCH
Nl4QQAEaRefer to GROUP 8
- Column Switch.
POWER STEERING OIL PRESSURE SWITCH
N14RCJBRefer to GROUP 19 for power steering system inspection.
INJECTORS
NWXAHCHECKING OPERATION SOUND
Using a sound-scope, check the operation sound (“chi-chi-chi”)of the injectors during idling or during cranking.
Check to be sure that the operation sound increases when the
engine speed is increased.
Caution
Note that the sounds of other injectors may be heard even
though the injector being checked is not operating, so caremust be taken when checking.
NOTEIf the operation sounds cannot be heard, check the injector
activation circuit.
If this circuit is normal, there is probably a malfunction of the
injector or of the engine control unit.
MEASURING OF RESISTANCE BETWEEN TERMINALS
(1) Disconnect the connector for the injectors.
(2) Measure the resistance between terminals.
Standard value:
13
-16 S2 [at 20°C (68”F)]2
- 3 52 [at 20% (68”F)]
(3) Connect the connector for the injectors.
IDLE SPEED CONTROL SERVO
N14QUADCHECKING OPERATING SOUND
(1) Check that when the ignition switch is placed in the ON
position (the engine not started), the operating sound of thestepper motor can be heard over the idle speed control
servo.
(2) If no operating sound can be heard, check the stepper
motor drive circuit.
(If the circuit is good, a defective stepper motor or engine
control unit is suspected.)

_-
FUEL SYSTEM - MPI System Inspection <2.0L DOHC Engine>'I4181
OlLO22Z
CONTROL RELAY
INSPECTIONNWWAC
(1) Remove the control relay.
(2) Use jumper wires and connect control relay terminal
@I to
the battery
@ terminal and terminal @ to the battery 0
terminal.Caution
Be very careful when connecting the jumper wires
because the relay will be damaged if a mistake is made
with the contact terminals.
(3) With battery
0 terminal jumper wire connected and
disconnected, measure the voltage at control relay termi-
nals
@I and 0.(4) Use jumper wires to connect control relay terminal
@ to
the battery
@ terminal and terminal @ to the battery 0
terminal.(5) With the battery
@ terminal jumper wire connected and
disconnected, measure the voltage at control relay termi-
nals
@I and 0.
Continuity between terminals 0-0
)(6) Use jumper wires and connect control relay terminal
@ to
the battery
@ terminal and terminal @ to the battery 0
terminal.(7) With the battery
0 terminal jumper wire disconnected,
measure the voltage at control relay terminal
0.
31(8) Replace the control relay if faulty.

14-82FUEL SYSTEM - MPI System Inspection <2.0L DOHC Engine>
\ \\I \3FUO352
,\ \
\I \3FUO353
,\ ‘\R/
\ \\I \3FUo354
POWER TRANSISTORRefer to GROUP 8
- Ignition System
NlIAcQAl
a-4
AIR CONDITIONER POWER RELAYN14NCl.a -Refer to GROUP 24
- Air Conditioner.
PURGE CONTROL SOLENOID VALVEN14RCKARefer to GROUP 25
- Evaporative Emission Control System.
EGR CONTROL SOLENOID VALVE
N14NCURefer to GROUP 25
- Exhaust Gas Recirculation System.
FUEL PRESSURE CONTROL VALVE
OPERATIONAL CHECK
NOTEBefore the vacuum hoses are removed, make a mark’on the
-
hose for visual identification so that they can be reconnected in,their original positions.
(1) Remove the vacuum hoses (blue stripes and black) from
the solenoid valve.
(2) Disconnect the harness connector.
(3) Apply vacuum with a hand vacuum pump to the nipple to
which the black vacuum hose was connected and check for
air tightness both when a voltage is applied to the solenoidvalve terminal and when the voltage is removed.
Battery voltageOther nipple of
solenoid valveNormal condition
When voltage
is removed
When voltage
is applied
OpenVacuum leaks
Blocked by fingerVacuum is retained
OpenVacuum is retainedCHECKING
COIL RESISTANCE
Measure the coil resistance with a tester.
Standard resistance: 36
- 46 R [at 20°C (68”F)]