Mitsubishi MOTORS Space Runner 1999 Workshop Manual Supplement page 418

INSPECTION PROCEDURE 18
To high CO and HC concentration when idling
The cause is probably an incorrect air/fuel ratio
MUT-II Self-Diag code
Is a diagnosis code displayed?
Check ignition timing. (Refer to GROUP 11A – Engine Adjustment.)
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-76.)
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-75.)
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-76.)
MUT-II Data list
11 Oxygen sensor
OK: 600 – 1,000 mV when the engine is suddenly raced
MUT-II Data list
11 Oxygen sensor
OK: 0 – 400 mV and 600 – 1,000 mV alternates when the
engine is idling (wait for four minutes after the engine
started).
Measure fuel high-pressure between the fuel pump (high pressure)
and injector. (Refer to P.13A-98.)
Check ignition coil spark for each cylinder.
(1) Remove the ignition coil.
(2) Install a new spark plug to the removed ignition coil.
(3) Disconnect the injector intermediate connector.
Caution
Never touch the connector terminal as approx. 100 V is applied to the injector, or you are seriously injured.
(4) Earth the spark plug electrode securely.
(5) Check that the spark plug ignites when the engine is cranked.
Check all the following items:
Spark plugs
EGR system
Compression pressure
Clogged fuel filter or line
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GDI –
No
OK
OK
OK
OK
OK
NG
OK
OK
OK
Troubleshooting
Probable cause
Malfunction of the air/fuel ratio control system
Deterioration of the catalyst
Yes
(Refer to P.13A-13, INSPECTION CHART FOR DIAGNOSIS
CODES.)
NG
Check that the crank angle sensor and timing belt cover are properly
installed.
NG
Check the engine coolant temperature sensor. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
NG
Check the intake air temperature sensor. (Refer to P.13A-16, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
NG
Check the barometric pressure sensor. (Refer to P.13A-22, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
NG
Check the oxygen sensor system. (Refer to P.13A-14, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
Replace the oxygen sensor.
Check trouble symptom.
NG
Repair
Replace the ignition coil.
13A-59
NG
NG