1997 MITSUBISHI TRITON Workshop Manual

S
ym pto m S
ta rtin g W
on't s ta rt T
he s ta rte r is u se d to c ra nk th e e ngin e, b ut th ere is n o c o m bustio n w it h in th e
c ylin ders , a nd th e e ngin e w on't s ta rt. F
ir e s u p a nd d ie s T
here is c o m bustio n w it h in th e c ylin ders , b ut th en th e e ngin e s o on s ta lls . H
ard s ta rtin g E
ngin e s ta rts a fte r c ra nkin g a w hile . I
d lin g s
ta bilit y H
untin g E
ngin e s p eed d oesn 't r e m ain c o nsta nt; c h anges a t id le . s
ta bilit y R
ough id le U
su ally , a ju dgem ent c a n b e b ase d u pon th e m ove m ent o f th e ta ch om ete r
p oin te r, a nd th e v ib ra tio n tr a nsm it te d to th e s te erin g w heel, s h if t le ve r, b ody, e tc .
T his is c a lle d r o ugh id le . I
n co rre ct id le s p eed T
he e ngin e d oesn 't id le a t th e u su al c o rre ct s p eed. E
ngin e s ta ll
( D ie o ut) T
he e ngin e s ta lls w hen th e fo ot is ta ke n fr o m th e a cce le ra to r p edal, r e gard le ss
o f w heth er th e v e hic le s is m ovin g o r n ot. E
ngin e s ta ll
( P ass o ut) T
he e ngin e s ta lls w hen th e a cce le ra to r p edal is d epre sse d o r w hile it is b ein g
u se d. D
riv in g H
esit a tio n S ag ª
H esit a tio nº is th e d ela y in r e sp onse o f th e v e hic le s p eed ( e ngin e s p eed) th at
o ccu rs w hen th e a cce le ra to r is d epre sse d in o rd er to a cce le ra te fr o m th e s p eed
a t w hic h th e v e hic le is n ow tr a ve lin g, o r a te m pora ry d ro p in v e hic le s p eed
( e ngin e s p eed) d urin g s u ch a cce le ra tio n.
S erio us h esit a tio n is c a lle d ª s a gº. ( R efe r to F ig . 1 ) P
oor a cce le ra tio n P
oor a cce le ra tio n is in abilit y to o bta in a n a cce le ra tio n c o rre sp ondin g to th e
d egre e o f th ro ttle o penin g, e ve n th ough a cce le ra tio n is s m ooth , o r th e in abilit y
t o r e ach m axim um s p eed. S
tu m ble E
ngin e s p eed in cre ase is d ela ye d w hen th e a cce le ra to r p edal is in it ia lly
d epre sse d fo r a cce le ra tio n. ( R efe r to F ig . 2 ) S
hock T
he fe elin g o f a c o m para tiv e ly la rg e im pact o r v ib ra tio n w hen th e e ngin e is
a cce le ra te d o r d ece le ra te d. S
urg e T
his is r e peate d s u rg in g a head d urin g c o nsta nt s p eed tr a ve l o r d urin g v a ria ble
s p eed tr a ve l. K
nockin g A
s h arp s o und lik e a h am mer s tr ik in g th e c ylin der w alls d urin g d riv in g a nd w hic h
a dve rs e ly a ff e cts d riv in g. S
to ppin g R
un o n
( ª D ie se lin gº) T
he c o ndit io n in w hic h th e e ngin e c o ntin ues to r u n a fte r th e ig nit io n s w it c h is
t u rn ed to O FF. A ls o c a lle d ª D ie se lin gº.

MPI ± Troubleshooting13A-23
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
INSPECTION PROCEDURE 1
Communication with MUT-II is not possible.
(Communication with all systems is not possible.)
Probable cause
The cause is probably a defect in the power supply system (including earth) for the
diagnosis line.
Malfunction of the connector

Malfunction of the harness wire
Measure at the diagnosis connector
(16-pin) C-35.

Voltage between 16 and earth
OK:Battery voltageNGCheck the following connectors.
A-56X, C-79, C-81NG
Repair
OK
Check trouble symptom.NGCheck the harness wire between the
power supply and diagnosis connector
(16 pin), and repair if necessary.OK
Measure at the diagnosis connector
(16-pin) C-35.

Continuity between 4 and earth

Continuity between 5 and earth
OK:ContinuityNG
OK
Replace the MUT-II.
Check the following connector.
C-86NG
Repair
OK
Check trouble symptom.NGCheck the harness wire between the
diagnosis connector (16-pin) and the
earth, and repair if necessary.

MPI ± Troubleshooting13A-24
INSPECTION PROCEDURE 2
MUT-II communication with engine-ECU is impossible.
Probable cause
One of the following causes may be suspected.

No power supply to engine-ECU.

Defective earth circuit of engine-ECU.

Defective engine-ECU.

Improper communication line between engine-ECU and MUT-II

Malfunction of engine-ECU power supply circuit

Malfunction of engine-ECU

Open circuit between engine-ECU and diagnosis
connector


Malfunction of engine-ECU power supply circuit

Malfunction of engine-ECU

Malfunction of immobilizer-ECU

Open circuit between immobilizer-ECU and diagnosis
connector

Open circuit between engine-ECU and immobilizer-
ECU
OK
Ye s
NG

Check the following connector. C-19NG
Repair
Check trouble symptom.
NG
Check the harness wire between engine-ECU and diagnosis con-
nector.OKCheck the harness wire
between engine-ECU and
earth.NG
Repair
OK
Check the power supply and ignition switch-IG system. (Refer to
P.13A-39, INSPECTION PROCEDURE 23.)

Repair
OKCheck the harness wire
between engine-ECU and
earth.NG
Repair
OK
Check the power supply and ignition switch-IG system. (Refer to
P.13A-39, INSPECTION PROCEDURE 23.)
NG
Check the harness wire between engine-ECU and immobilizer-
ECU.
OK
Check trouble symptom.
Check the following connectors. C-19, C-36NG
Repair
Is communication possible between the MUT-II and the immobilizer-
ECU?NoCheck the diagnosis line between the immobilizer-ECU and the
MUT-II, and repair if necessary. (Refer to GROUP 54 ± Ignition
Key and Immobilizer.)
NG
Repair

MPI ± Troubleshooting13A-25
INSPECTION PROCEDURE 3
The engine warning lamp does not illuminate right after
the ignition switch is turned to the ON position.
Probable cause
Because there is a burnt-out bulb, the engine-ECU causes the engine warning lamp
to illuminate for five seconds immediately after the ignition switch is turned to ON.
If the engine warning lamp does not illuminate immediately after the ignition switch
is turned to ON, one of the malfunctions listed at right has probably occurred.
Burnt-out bulb

Defective warning lamp circuit

Malfunction of the engine-ECU
MUT-II Data list
16 engine-ECU power supply voltage (Refer to P.13A-58.)NGCheck the engine-ECU power supply and earth circuit.
(Refer to P.13A-53, INSPECTION PROCEDURE 42.)
OK
Measure at the engine-ECU connector C-50.

Disconnect the connector, and measure at the harness side.

Earth the terminal No. 36.
OK:The engine warning lamp illuminates.OKCheck the following
connector. C-50.NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
NG
Check a burnt-out bulb.NG
Replace
OK
Measure at the combination meter connector C-06.

Disconnect the connector, and measure at the harness side.

Voltage between 43 and earth (Ignition switch: ON)
OK:System voltageNGCheck the engine warning lamp power supply circuit, and repair
if necessary.
OK
Check the following connectors.
C-04, C-06, C-19, C-50NG
Repair
OK
Check trouble symptom.NGCheck the harness wire between combination meter and engine-
ECU, and repair if necessary.
INSPECTION PROCEDURE 4
The engine warning lamp remains illuminating and never
goes out.
Probable cause
In cases such as the above, the cause is probably that the engine-ECU is detecting
a problem in a sensor or actuator, or that one of the malfunctions listed at right has
occurred.
Short-circuit between the engine warning lamp and
engine-ECU

Malfunction of the engine-ECU
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES
No
Measure at the combination meter connector C-04.

Disconnect the connector, and measure at the harness side.

Disconnect the engine-ECU connector

Continuity between 8 and earth
OK:No continuityNGCheck the harness wire between combination meter and engine-
ECU connector, and repair if necessary.
OK
Replace the engine-ECU.

MPI ± Troubleshooting13A-26
INSPECTION PROCEDURE 5
No initial combustion (starting impossible)
Probable cause
In cases such as the above, the cause is probably that a spark plug is defective,
or that the supply of fuel to the combustion chamber is defective.
In addition, foreign materials (water, kerosene, etc.) may be mixed with the fuel.
Malfunction of the ignition system

Malfunction of the fuel pump system

Malfunction of the injectors

Malfunction of the engine-ECU

Malfunction of the immobilizer system with immobilizer system>

Foreign materials in fuel
Check battery voltage when cranking.
OK:8 V or higherNGCheck the battery. (Refer to GROUP 54 ± Battery.)
OK
Is immobilizer-ECU diagnosis code displayed? immobilizer system>Ye sCheck the immobilizer.
(Refer to GROUP 54 ± Ignition Key and Immobilizer.)
No
MUT-II: Inspection of no initial combustion.
(Refer to P.13A-47, INSPECTION PROCEDURE 34.)
OK
Can any sound be heard from the injectors when cranking?NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Ignition system: Inspection of no initial combustion.
(Refer to P.13A-47, INSPECTION PROCEDURE 35.)
OK
Check the following items.

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

Check if the injectors are clogged.

Check if foreign materials (water, alcohol, etc.) got into fuel.

Check the compression pressure.

Check the immobilizer system. (Refer to GROUP 54 ± Ignition Key and Immobilizer.)

MPI ± Troubleshooting13A-27
INSPECTION PROCEDURE 6
Initial combustion but no complete combustion
(starting impossible)
Probable cause
In such cases as the above, the cause is probably that the spark plugs are generating
sparks but the sparks are weak, or the initial mixture for starting is not appropriate.
Malfunction of the ignition system

Malfunction of the injector system

Foreign materials in fuel

Poor compression

Malfunction of the engine-ECU
Check battery voltage when cranking.
OK:8 V or higherNGCheck the battery. (Refer to GROUP 54 ± Battery.)
OK
MUT-II: Check if uncompleted combustion occurs.
(Refer to P.13A-48, INSPECTION PROCEDURE 36.)
OK
Can any sound be heard from the injectors when cranking?NGCheck the injector system, (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Is starting good if the engine is cranked with the accelerator pedal
slightly depressed?Ye sCheck ISC servo for op-
eration sound.
(Refer to P.13A-90.)NGCheck the ISC servo sys-
tem. (Refer to P.13A-45,
INSPECTION PROCE-
DURE 31.)
OK

Clean the throttle valve area. (Refer to P.13A-78.)

Check and adjust the fixed SAS. (Refer to P.13A-79.)
No
Check the ignition timing when cranking.
OK:Approx. 5BTDCNGCheck that the distributor is installed properly.
OK
Check the following items.

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

Check if the injectors are clogged.

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

Check fuel lines for clogging.

Check if foreign materials (water, alcohol, etc.) got into fuel.

MPI ± Troubleshooting13A-28
INSPECTION PROCEDURE 7
In takes too long time to start. (Incorrect starting)
Probable cause
In cases such as the above, the cause is probably that the spark is weak and ignition
is difficult, the initial mixture for starting is not appropriate, or sufficient compression
pressure is not being obtained.
Malfunction of the ignition system

Malfunction of the injector system

Inappropriate gasoline use

Poor compression
Check battery voltage when cranking
OK:8 V or higherNGCheck the battery. (Refer to GROUP 54 ± Battery.)
OK
MUT-II: Check if uncomplete combustion occurs.
(Refer to P.13A-48, INSPECTION PROCEDURE 36.)
OK
Can any sound be heard from the injectors when cranking?NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing when cranking.
OK:Approx. 5BTDCNGCheck that the distributor is installed properly.
OK
Check the following items.

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

Check if the injectors are clogged.

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

Check if foreign materials (water, alcohol, etc.) got into fuel.

MPI ± Troubleshooting13A-29
INSPECTION PROCEDURE 8
Unstable idling (Rough idling, hunting)
Probable cause
In cases as the above, the cause is probably that the ignition system, air/fuel mixture,
idle speed control (ISC) or compression pressure is defective.
Because the range of possible causes is broad, inspection is narrowed down to simple
items.
Malfunction of the ignition system

Malfunction of air-fuel ratio control system

Malfunction of the ISC system

Malfunction of the purge control solenoid valve system

Malfunction of the EGR solenoid valve system

Poor compression

Drawing air into exhaust system
Were the battery terminals disconnected?Ye sAfter warming-up, let the engine run at idling for 10 minutes.
No
MUT-II Self-Diag code
Are diagnosis codes displayed?Ye sRefer to P.13A-10, INSPECTION CHART FOR DIAGNOSIS
CODES.
No
Does idling speed fluctuate excessively?Ye sCheck if hunting occurs.
(Refer to P.13A-48, INSPECTION PROCEDURE 37.)
No
Check the ISC servo for operation sound. (Refer to P.13A-90.)NGCheck the ISC servo system.
(Refer to P.13A-45, INSPECTION PROCEDURE 31.)
OK
Check the injector for operation sound.NGCheck the injector system. (Refer to P.13A-19, INSPECTION PRO-
CEDURE FOR DIAGNOSIS CODE 41.)
OK
MUT-II: Check if idling speed is unstable.
(Refer to P.13A-49, INSPECTION PROCEDURE 38.)
OK
Check the ignition timing.
(Refer to GROUP 11 ± On-vehicle Service.)NGCheck that the distributor is installed properly.
OK
Check the following items.

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

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

Check if foreign materials (water, alcohol, etc.) got into fuel.