engine coolant MITSUBISHI TRITON 1997 User Guide

MPI ± Troubleshooting13A-38
INSPECTION PROCEDURE 22
Too high CO and HC concentration when idling
Probable cause
Abnormal air-fuel ratio is suspected.
Malfunction of the air-fuel ratio control system

Deteriorated catalyst
Check trouble symptom.
No
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
MUT-II Data list
21 Engine coolant temperature sensor. (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air temperature sensor system. (Refer to P.13A-12,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-57.)NGCheck the barometric pressure sensor system. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
11 Oxygen sensor
OK:600 ± 1,000 mV when racing suddenly (Refer to P.13A-57.)NGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Repeat 0 ± 400 mV and 600 ± 1,000 mV alternately when
idling. (Refer to P.13A-57.)OK
NG
Check the fuel pressure. (Refer to P.13A-81.)
OK
NG
Check the following items.

Check the injectors for operation sound.

Check the injectors for fuel leakage.

Check the ignition coil, spark plugs, spark plug cables. (Refer to GROUP 16 ± On-vehicle Service.)

Check the compression pressure. (Refer to GROUP 11 ± On-vehicle Service.)

Check the positive crankcase ventilation system. (Refer to GROUP 17 ± Emission Control System.)

Check the purge control system. (Refer to GROUP 17 ± Emission Control System.)

Check the EGR control system. (Refer to GROUP 17 ± Emission Control System.)
Check the trouble symptom.
NG
Replace the catalytic converter.
Replace the oxygen sensor.
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.

MPI ± Troubleshooting13A-47
INSPECTION PROCEDURE 34
MUT-II: Inspection of no initial combustion
MUT-II Data list
16 Voltage of engine-ECU power source (Refer to P.13A-57.)NGCheck the power supply and ignition switch-IG system.
(Refer to P.13A-39, INSPECTION PROCEDURE 23.)
OK
Does the camshaft rotate at the engine cranking?
(When oil filler cap is removed.)NoCheck timing belt for breakage.
Ye s
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
MUT-II Data list
22 Crank angle sensor
OK:Cranking speed is displayed.NoCheck the crank angle sensor system.
(Refer to P.13A-15, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 22.)
OK
MUT-II Actuator test
07 Fuel pump (Refer to P.13A-62.)NGCheck the fuel pump system.
(Refer to P.13A-40, INSPECTION PROCEDURE 24.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
INSPECTION PROCEDURE 35
Ignition system: Inspection of no initial combustion.
Does the engine tachometer display the cranking speed?

Set the tachometer of primary voltage detection type.NGCheck ignition circuit system.
(Refer to P.13A-44, INSPECTION PROCEDURE 30.)
OK
Check the ignition timing when cranking.
OK:Approx. 5BTDCNGCheck that the crank angle sensor is installed properly.

MPI ± Troubleshooting13A-48
INSPECTION PROCEDURE 36
MUT-II: Check if uncomplete combustion occurs.
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS CODE
No
MUT-II Actuator test
07 Fuel pump (Refer to P.13A-62.)NGCheck the fuel pump system.
(Refer to P.13A-40, INSPECTION PROCEDURE 24.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURES FOR DIAGNO-
SIS CODE 21.)
OK
MUT-II Data list
18 Ignition switch-ST (Refer to P.13A-57.)NGCheck the ignition switch-ST system .
(Refer to P.13A-41, INSPECTION PROCEDURE 26.)
INSPECTION PROCEDURE 37
Check if hunting occurs.
Clean the throttle body. (Refer to P.13A-78.)
Check and adjust the fixed SAS. (Refer to P.13A-79.)
Check trouble symptom.
NG
Inspect the intake of air into the air intake system

Broken intake manifold gasket

Broken air intake hose

Broken vacuum hose

Positive crankcase ventilation valve does not operate.

MPI ± Troubleshooting13A-49
INSPECTION PROCEDURE 38
MUT-II: Check if idling speed is unstable.
OK
MUT-II Data list
26 Idle position switch (Refer to P.13A-57.)NGCheck the idle position switch system.
(Refer to P.13A-40, INSPECTION PROCEDURE 25.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air temperature sensor system. (Refer to P.13A-12,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-57.)NGCheck the barometric pressure sensor system. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Actuator test
08 Purge control solenoid valve (Refer to P.13A-62.)NGCheck the purge control solenoid valve system
(Refer to P.13A-45, INSPECTION PROCEDURE 32.)
MUT-II Data list
11 Oxygen sensor
OK:600 ±1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0 ±400 mV and 600 ±1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system.

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.
OK
MUT-II Data list
27 Power steering fluid pressure switch (Refer to P.13A-57.)NGCheck the power steering
fluid pressure switch sys-
tem. (Refer to P.13A-43,
INSPECTION PROCE-
DURE 28.)
OK
MUT-II Data list
28 A/C switch (Refer to P.13A-57.)NGCheck the A/C switch and A/C relay system.
(Refer to P.13A-43. INSPECTION PROCEDURE 29.)
OK
MUT-II Data list
29 Inhibitor switch (Refer to P.13A-57.)NGCheck the ignition switch-ST and inhibitor switch system.
(Refer to P.13A-42, INSPECTION PROCEDURE 27.)
OK
MUT-II Data list
45 ISC Servo position (Refer to P.13A-57.)NGAdjust the basic idle speed. (Refer to P.13A-79.)
OK
MUT-II Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system. (Refer to P.13A-46,
INSPECTION PROCEDURE 33.)

MPI ± Troubleshooting13A-50
INSPECTION PROCEDURE 39
MUT-II: Engine stalling inspection when the engine is warmed up and idling.
MUT-II Data list
26 Idle position switch (Refer to P.13A-57.)NGCheck the idle position switch system.
(Refer to P.13A-40, INSPECTION PROCEDURE 25.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air sensor system. (Refer to P.13A-12, INSPEC-
TION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-57.)NGCheck the barometric pressure sensor system. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0 ± 400 mV and 600 ± 1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.
OK
MUT-II Data list
27 Power steering fluid pressure switch (Refer to P.13A-57.)NGCheck the power steering
fluid pressure switch sys-
tem. (Refer to P.13A-43,
INSPECTION PROCE-
DURE 28.)
OK
MUT-II Data list
28 A/C switch (Refer to P.13A-57.)NGCheck the A/C switch and A/C relay system.
(Refer to P.13A-43, INSPECTION PROCEDURE 29.)
OK
MUT-II Data list
29 Inhibitor switch (Refer to P.13A-57.)NGCheck the ignition switch-ST and inhibitor switch system.
(Refer to P.13A-42, INSPECTION PROCEDURE 27.)
OK
MUT-II Data list
45 ISC servo position (Refer to P.13A-57.)NGAdjust the basic idle speed. (Refer to P.13A-79.)
OK
MUT-II Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system. (Refer to P.13A-46,
INSPECTION PROCEDURE 33.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 600 ± 1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)

MPI ± Troubleshooting13A-51
INSPECTION PROCEDURE 40
MUT-II: Check if hesitation, sug, stumble or poor acceleration occurs.
MUT-II Data list
26 Idle position switch (Refer to P.13A-57.)NGCheck the idle position switch system.
(Refer to P.13A-40, INSPECTION PROCEDURE 25.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air sensor system. (Refer to P.13A-12, INSPEC-
TION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-57.)NGCheck the barometric pressure sensor system. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOS-
TIC CODE 21.)
OK
MUT-II Data list
14 Throttle position sensor (Refer to P.13A-57.)NGCheck the throttle position sensor system. (Refer to P.13A-13, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system.
(Refer to P.13A-46, INSPECTION PROCEDURE 33.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 600 ± 1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0 ± 400 mV and 600 ± 1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.

MPI ± Troubleshooting13A-52
INSPECTION PROCEDURE 41
MUT-II: Check if surge occurs.
MUT-II Data list
26 Idle position switch (Refer to P.13A-57.)NGCheck the idle position switch system.
(Refer to P.13A-40, INSPECTION PROCEDURE 25.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air sensor system. (Refer to P.13A-12, INSPEC-
TION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-57.)NGCheck the barometric pressure sensor system. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
14 Throttle position sensor (Refer to P.13A-57.)NGCheck the throttle position sensor system. (Refer to P.13A-13, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system.
(Refer to P.s13A-46, INSPECTION PROCEDURE 33.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 600 ± 1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0 ± 400 mV and 600 ± 1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.

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