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.
17-2
EXHAUST GAS RECIRCULATION (EGR)
SYSTEM 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Information 14. . . . . . . . . . . . . . . . . . . . . .
Operation 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Diagram 14. . . . . . . . . . . . . . . . . . . . . . . . .
Component Location 14. . . . . . . . . . . . . . . . . . . . .
Exhaust Gas Recirculation (EGR) Control
System Check 15. . . . . . . . . . . . . . . . . . . . . . . . . . EGR Valve Check 15. . . . . . . . . . . . . . . . . . . . . . . .
EGR Port Vacuum Check 16. . . . . . . . . . . . . . . . .
EGR Control Solenoid Valve Check 16. . . . . . .
CATALYTIC CONVERTER 17. . . . . . . . . . . . . . .
General Information 17. . . . . . . . . . . . . . . . . . . . . .
CANISTER AND TWO-WAY VALVE 18. . . . . .
± Emission Control System ENGINE AND
EMISSION CONTROL17-6
EMISSION CONTROL SYSTEM 17300010184
GENERAL INFORMATION
The emission control system consists of the following subsystems:
Crankcase emission control system
Evaporative emission control system
Exhaust emission control system
ItemsNameSpecification
Crankcase emission
control systemPositive crankcase ventilation (PCV) valveVariable flow type
(Purpose: HC reduction)
Evaporative emission
control systemCanister
Purge control solenoid valveEquipped
ON/OFF type solenoid valve
(Purpose: HC reduction)
Exhaust emission
control systemAir-fuel ratio control device±MPI systemOxygen sensor feedback type
(Purpose: CO, HC, NOx reduction)
Exhaust gas recirculation system
EGR valve
EGR control solenoid valveEquipped
Single type
Duty cycle type solenoid valve
(Purpose: NOx reduction)
Catalytic converterMonolith type
(Purpose: CO, HC, NOx reduction)
EMISSION CONTROL DEVICE REFERENCE TABLE
Related partsCrankcase
emission
control
systemEvaporative
emission
control
systemAir/fuel
ratio
control
systemCatalytic
converterExhaust
gas
recircula-
tion systemReference
page
PCV valvey17-
Purge control solenoid valvey17-
MPI system componentyyGROUP 13A
Catalytic convertery17-
EGR valvey17-
EGR control solenoid valvey17-
