1997 MITSUBISHI TRITON Workshop Manual

MPI ± Troubleshooting13A-54
INSPECTION PROCEDURE 44
Check the fuel pump drive control circuit.
Measure at the fuel pump relay connector C-54.

Disconnect the connector and measure at the harness side.

Voltage between 4 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connector. C-88NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between fuel pump relay
and ignition switch con-
nector.NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54 ± Ignition Switch and Immobilizer System.)
OK
Measure at the engine-ECU connector C-49.

Disconnect the connector and measure at the harness side.


Voltage between 8 and earth (Ignition switch: ON)
OK:System voltage


Voltage between 22 and earth (Ignition switch: ON)
OK:System voltageNG
Check the following
connector. C-54NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and fuel pump relay
connector, and repair if necessary.
OK
Check the following connector. C-49NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
INSPECTION PROCEDURE 45
Check air flow sensor (AFS) control circuit.
Measure at the air flow sensor connector A-77.

Disconnect the connector and measure at the harness side.
1. Voltage between 4 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 3 and earth (Ignition switch: ON)
OK:4.8 ± 5.2 V
3. Continuity between 5 and earth
OK:Continuity1. NGCheck the harness wire between the air flow sensor and control
relay connector, and repair if necessary.
2, 3. NGCheck the following
connector. C-51NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and air flow sensor con-
nector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following connector. A-77NG
Repair
OK
Check trouble symptom.
NG
Replace the air flow sensor.

MPI ± Troubleshooting13A-55
INSPECTION PROCEDURE 46
Check throttle position sensor (TPS) output circuit.
Measure at the engine-ECU connector C-51.

Connect the connector.

Voltage between 64 and earth (Ignition switch: ON)
OK:0.3 ± 1.0 V (Throttle valve at idle position)
4.5 ± 5.5 V (Throttle valve fully open)OKCheck the following
connector. C-51NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
NG
Check the following connector. A-47
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and throttle position
sensor connector, and repair if necessary.NG
Repair
INSPECTION PROCEDURE 47
Check injector control circuit
Measure at the engine-ECU connector C-49.

Disconnect the connector and measure at the harness side.

Voltage between 1, 14 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connectors.
A-45, A-46, A-57, A-61NG
Repair
OK
Check trouble symptom.
NG
Check the harness between engine-ECU and injector connector,
and repair if necessary.
OK
Check the following connector. C-49
OK
Check trouble symptom.
NG
Replace the engine-ECU.NG
Repair

MPI ± Troubleshooting13A-56
INSPECTION PROCEDURE 48
Check ignition coil and power transistor unit circuit.
Check the ignition coil. (Refer to GROUP 16 ± Ignition System.)NG
Replace
OK
Check the power transistor unit.
(Refer to GROUP 16 ± Ignition System.)NG
Replace
OK
Measure at the power transistor unit connector A-70.

Disconnect the connector and measure at the harness side.
1. Voltage between 3 and earth (Ignition switch: ON)
OK: System voltage
2. Voltage between 1 and earth (Engine: Cranking)
OK: 2 ± 7 V1. OKCheck the following
connector. A-65NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and the power transistor
unit, and repair if neces-
sary.NG
Repair
NG
As short circuit occurs between power transistor unit and combina-
tion meter (tachometer), check the harness wire, and repair if neces-
sary.
OK
Check the following connectors, and repair if necessary.
A-65, A-70NG
Check the harness wire between the power transistor unit and
ignition coil connector, and repair if necessary. 2. NG
Check the following
connector. C-49NG
Repair
OK
Check trouble symptom. OK
Measure at the power transistor unit connector A-70.

Disconnect the connector and measure at the harness side.

Disconnect the ignition coil connector.

Continuity between 3 and earth
OK: No continuity
OK
Replace the engine-ECU.

MPI ± Troubleshooting13A-57
DATA LIST REFERENCE TABLE13100890180
Caution
When shifting the select lever to D range, the brakes should be applied so that the vehicle does
not move forward.
NOTE
*1. In a new vehicle [driven approximately 500 km or less], the air flow sensor output frequency is sometimes
10% higher than the standard frequency.
*
2. The idle position switch normally turns off when the voltage of the throttle position sensor is 50 ±
100 mV higher than the voltage at the idle position. If the idle position switch turns back on after
the throttle position sensor voltage has been by 100 mV and the throttle valve has been opened,
the idle position switch and the throttle position sensor need to be adjusted.
*3. The injector drive time represents the time when the cranking speed is at 250 r/min or below when
the power supply voltage is 11 V.
*4. In a new vehicle [driven approximately 500 km or less], the injector drive time is sometimes 10%
longer than the standard time.
*5. In a new vehicle [driven approximately 500 km or less], the step of the stepper motor is sometimes
30 steps greater than the standard value.
Item
No.Inspection
itemInspection contentsNormal conditionInspection
procedure
No.Reference
page
11Oxygen
sensorEngine:After having
warmed up
Air/fuel mixture is
made leaner when de-
When at 4,000 r/min,
engine is suddenly
decelerated200 mV or lessCode No.
1113A-11
made leaner when de-
celerating, and is made
richer when racing.
When engine is
suddenly raced600 ± 1,000 mV
Engine:After having
warmed up
The oxygen sensor
signal is used to check
the air/fuel mixture
ratio and control
Engine is idling400 mV or less
(Changes)
600 ± 1,000 mV
ratio, and control
condition by the en-
gine-ECU.2,500 r/min400 mV or less
(Changes)
600 ± 1,000 mV
12Air flow
sensor*1
Engine coolant
temperature:
80 ± 95C

Lamps and all
accessories: OFF
Engine is idling22 ± 48 Hz
<4G63>
19 ± 45 Hz
<4G64>±±
accessories: OFF

Transmission:
Neutral (A/T:
P range)2,500 r/min80 ± 120 Hz
<4G63>
67 ± 107 Hz
<4G64>
Engine is racedFrequency
increases in
response to
racing

MPI ± Troubleshooting13A-58
Item
No.Reference
page Inspection
procedure
No. Normal condition Inspection contents Inspection
item
13Intake air
temperature
sensor
Ignition switch: ON or
with engine runningWhen intake air
temperature is ±20
C±20
CCode No.
1313A-12
sensorWhen intake air
temperature is 0
C0
C
When intake air
temperature is 20
C20
C
When intake air
temperature is 40
C40
C
When intake air
temperature is 80
C80
C
14Throttle
p
osition
Ignition switch: ONSet to idle position300 ± 1,000 mVCode No.
14
13A-13
osition
sensorGradually openIncreases in
proportion to
throttle opening
angle
14
Open fully4,500 ± 5,500 mV
16Power
supply
voltageIgnition switch: ONSystem voltageProcedure
No. 2313A-39
18Cranking
signal
(ignition
it h ST)
Ignition switch: ONEngine: StoppedOFFProcedure
No. 26
13A-41

13A-42
switch-ST)Engine: CrankingONProcedure
No. 27

21Engine
coolant
temperature
sensor
Ignition switch: ON or
with engine runningWhen engine
coolant temperature
is ±20
C±20
CCode No.
2113A-14
sensor
When engine
coolant temperature
is 0
C0
C
When engine
coolant temperature
is 20
C20
C
When engine
coolant temperature
is 40
C40
C
When engine
coolant temperature
is 80
C80
C

MPI ± Troubleshooting13A-59
Item
No.Reference
page Inspection
procedure
No. Normal condition Inspection contents Inspection
item
22Crank angle
sensor
Engine: Cranking

Tachometer:
ConnectedCompare the engine
speed readings on
the tachometer and
the MUT-II.AccordCode No.
2213A-15

Engine: Idling

Idle position
switch: ONWhen engine
coolant temperature
is ±20C1,275 ± 1,475 r/min
When engine
coolant temperature
is 0C1,225 ± 1,425 r/min
When engine
coolant temperature
is 20C1,100 ± 1,300 r/min
When engine
coolant temperature
is 40C950 ± 1,150 r/min
When engine
coolant temperature
is 80C650 ± 850 r/min
25Barometric
p
ressure
Ignition switch: ONAt altitude of 0 m101 kPaCode No.
25
13A-18
ressure
sensorAt altitude of 600 m95 kPa
25
At altitude of 1,200 m88 kPa
At altitude of 1,800 m81 kPa
26Idle position
switchIgnition switch: ON
Check by operating
acceleratorpedal
Throttle valve:
Set to idle positionONProcedure
No. 2513A-40
accelerator pedal
repeatedlyThrottle valve:
Slightly openOFF*2
27Power
steering fluid
p
ressure
Engine: IdlingSteering wheel
stationaryOFFProcedure
No. 2813A-43
pressure
switchSteering wheel
turningON

MPI ± Troubleshooting13A-60
Item
No.Reference
page Inspection
procedure
No. Normal condition Inspection contents Inspection
item
28A/C switchEngine: Idling
(when A/C switch isA/C switch: OFFOFFProcedure
No. 2913A-43
(
ON, A/C compressor
should be operating.)A/C switch: ONON
29Inhibitor
switch
Ignition switch: ONP or NP or NProcedure
No 27
13A-42
switch
D, 2, L or RD, 2, L or R
No. 27
41Injectors *3Engine: CrankingWhen engine cool-
ant temperature is
0C51 ± 76 ms
<4G63>
60 ± 90 ms
<4G64>±±
When engine
coolant temperature
is 20C26 ± 38 ms
<4G63>
30 ± 45 ms
<4G64>
When engine
coolant temperature
is 80C5.7 ± 8.5 ms
<4G63>
6.7 ± 10.1 ms
<4G64>
Injectors*4
Engine coolant
temperature:
80 ± 95C

Lamps and all
accessories: OFF
Engine is idling1.9 ± 3.1 ms
<4G63>
2.2 ± 3.4 ms
<4G64>
accessories: OFF

Transmission:
Neutral (A/T :
P range)2,500 r/min1.8 ± 3.0 ms
<4G63>
1.9 ± 3.1 ms
<4G64>
When engine is
suddenly racedIncreases
44Ignition coils
and power
Engine: After
having warmed upEngine is idling2±18BTDC±±
transistors
g

Timing lamp is set.
(The timing lamp
is set in order to
check actual
ignition timing.)2,500 r/min23 ± 43 BTDC
<4G63>
27 ± 47 BTDC
<4G64>

MPI ± Troubleshooting13A-61
Item
No.Reference
page Inspection
procedure
No. Normal condition Inspection contents Inspection
item
45ISC
(stepper)
motor
p
osition*5

Engine coolant
temperature:
80 ± 95C

Lamps and all
A/C switch: OFF2 ± 25 STEP±±
osition 5
Lam s and all
accessories: OFF

Transmission:
Neutral (A/T :
P range)

Idleposition
A/C switch:
OFF
ONIncreases by
10 ± 70 steps

Idle osition
switch: ON

Engine: Idling

When A/C switch
is ON, A/C
compressor should
be operating
A/C switch: OFF

Select lever:
N range
D
rangeIncreases by
5 ± 50 steps
49A/C relayEngine: After having
warmed up/Engine is
idlingA/C switch: OFFOFF (Compressor
clutch is not
operating)Procedure
No. 2913A-43
A/C switch: ONON (Compressor
clutch is
operating)