ENGINE CONTROL SYSTEM
EC-1029
< SERVICE INFOMATION >
[MR TYPE 2] C
D E
F
G H
I
J
K L
M A EC
NP
O
The mixture ratio feedback system provides the best air/
fuel mixture ratio for drivability and emission control.
The three way catalyst (manifold) can then better r educe CO, HC and NOx emissions. This system uses air
fuel ratio (A/F) sensor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The
ECM adjusts the injection pulse width according to the sensor voltage signal. For more information about air
fuel ratio (A/F) sensor 1, refer to EC-1210 . This maintains the mixture ratio within the range of stoichiometric
(ideal air/fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the th ree way catalyst (manifold). Even if the switching
characteristics of air fuel ratio (A/F) sensor 1 shift, the air/fuel ratio is controlled to stoichiometric by the signal
from heated oxygen sensor 2.
Open Loop Control The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
• Deceleration and acceleration
• High-load, high-speed operation
• Malfunction of air fuel ratio (A/F) sensor 1 or its circuit
• Insufficient activation of air fuel ratio (A /F) sensor 1 at low engine coolant temperature
• High engine coolant temperature
• During warm-up
• After shifting from N to D (A/T and CVT models)
• When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL The mixture ratio feedback control system monitors the mixture ratio signal transmitted from air fuel ratio (A/F)
sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to
the theoretical mixture ratio as possible. However, the bas ic mixture ratio is not necessarily controlled as orig-
inally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during operation (i.e., fuel injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value co mpared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensati on used to maintain the mixture ratio at its theoretical
value. The signal from air fuel ratio (A/F) sensor 1 i ndicates whether the mixture ratio is RICH or LEAN com-
pared to the theoretical value. The signal then triggers a r eduction in fuel volume if the mixture ratio is rich, and
an increase in fuel volume if it is lean.
“Long term fuel trim” is overall fuel compensation ca rried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycl e according to the firing order. This system is used
when the engine is running.
Simultaneous Multiport Fuel Injection System Fuel is injected simultaneously into all four cylinders twice each engine cycle. In other words, pulse signals of
the same width are simultaneously transmitted from the ECM.
The four fuel injectors will then receive the signals two times for each engine cycle. SEF337W
EC-1036< SERVICE INFOMATION >
[MR TYPE 2]
EVAPORATIVE EMISSION SYSTEM
EVAPORATIVE EMISSION SYSTEM
Description INFOID:0000000004499914
SYSTEM DESCRIPTION
The evaporative emission system is used to reduce hydr ocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplis hed by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into t he EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not oper ating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating. EVAP canister purge volume contro l solenoid valve is controlled by ECM. When the
engine operates, the flow rate of vapor controlled by EVAP canister purge volume control solenoid valve is
proportionally regulated as the air flow increases.
EVAP canister purge volume control solenoid valve al so shuts off the vapor purge line during decelerating.
EVAPORATIVE EMISSION LINE DRAWING PBIB3639E
EVAPORATIVE EMISSION SYSTEM
EC-1039
< SERVICE INFOMATION >
[MR TYPE 2] C
D E
F
G H
I
J
K L
M A EC
NP
O
Check EVAP canister as follows:
1. Block port B.
2. Blow air into port Aand check that it flows freely out of port C.
3. Release blocked port B.
4. Apply vacuum pressure to port Band check that vacuum pres-
sure exists at the ports A and C.
5. Block port A and B.
6. Apply pressure to port Cand check that there is no leakage.
FUEL TANK VACUUM RELIEF VALVE (BUILT INTO FUEL FILLER CAP) 1. Wipe clean valve housing.
2. Check valve opening pressure and vacuum.
3. If out of specificat ion, replace fuel filler cap as an assembly.
CAUTION:
Use only a genuine fuel filler cap as a replacement. If an incor-
rect fuel filler cap is used, the MIL may come on.
EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Refer to EC-1329, " Component Inspection " .
FUEL TANK TEMPERATURE SENSOR Refer to EC-1273, " Component Inspection " .
EVAP CANISTER VENT CONTROL VALVE Refer to EC-1340, " Component Inspection " .
EVAP CONTROL SYSTEM PRESSURE SENSOR Refer to EC-1350, " Component Inspection " .
EVAP SERVICE PORT PBIB1212E
SEF445Y
Pressure: 15.3 - 20.0 kPa
(0.156 - 0.204 kg/cm 2
, 2.22 - 2.90 psi)
Vacuum: −6.0 to −3.4 kPa
( − 0.061 to −0.035 kg/cm 2
, −0.87 to −0.48 psi) SEF943S
EC-1040< SERVICE INFOMATION >
[MR TYPE 2]
EVAPORATIVE EMISSION SYSTEM
Positive pressure is delivered to the EVAP system through the EVAP
service port. If fuel vapor leak age in the EVAP system occurs, use a
leak detector to locate the leak.
Removal and Installation INFOID:0000000004499916
EVAP CANISTER
Tighten EVAP canister as shown in the figure.
EVAP CANISTER VENT CONTROL VALVE
1. Turn EVAP canister vent control valve counterclockwise.
• Lock (A)
• Unlock (B)
2. Remove the EVAP canister vent control valve.
Always replace O-ring with a new one.
How to Detect Fuel Vapor Leakage INFOID:0000000004499917
CAUTION:
• Never use compressed air or a high pressure pump.
• Do not exceed 4.12 kPa (0.042 kg/cm 2
, 0.6 psi) of pressure in EVAP system.
NOTE:
• Do not start engine.
• Improper installation of EVAP service port adapter to the EVAP service port may cause a leak.
WITH CONSULT-III
1. Attach the EVAP service port adapter securely to the EVAP service port.
2. Also attach the pressure pump and hose to the EVAP service port adapter. SEF462UC
PBIB1214E
PBIB3091E
EC-1042< SERVICE INFOMATION >
[MR TYPE 2]
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
System Description INFOID:0000000004499918
From the beginning of refueling, the air and vapor insi de the fuel tank go through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The vapor is absorbed by the EVAP canister and the air is
released to the atmosphere.
When the refueling has reached the full level of the fuel tank, the refueling EVAP vapor cut valve is closed and
refueling is stopped because of auto shut-off. The vapor which was absorbed by the EVAP canister is purged
during driving.
WARNING:
When conducting inspections below, be sure to observe the following:
• Put a “CAUTION: FLAMMABLE” sign in workshop.
• Do not smoke while servicing fuel system. Keep open flames and sparks away from work area.
• Be sure to furnish the workshop with a CO 2
fire extinguisher.
CAUTION:
• Before removing fuel line parts, carry out the following procedures:
- Put drained fuel in an explosion-pr oof container and put lid on securely.
- Release fuel pressure from fuel line. Refer to EC-1086, " Fuel Pressure Check " .
- Disconnect negative battery cable.
• Always replace O-ring when the fu el gauge retainer is removed.
• Do not kink or twist hose and tube when they are installed.
• Do not tighten hose and clamps excessively to avoid damaging hoses.
• After installation, run engine an d check for fuel leaks at connection.
• Do not attempt to top off the fuel tank afte r the fuel pump nozzle shuts off automatically.
Continued refueling may cause fuel overflow, r esulting in fuel spray and possibly a fire.
Diagnosis Procedure INFOID:0000000004499919
SYMPTOM: FUEL ODOR FROM EVAP CANISTER IS STRONG. 1.
CHECK EVAP CANISTER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor
attached.
2. Weigh the EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor
attached.
The weight should be l ess than 1.9 kg (4.2 lb).
OK or NG OK >> GO TO 2.
NG >> GO TO 3. 2.
CHECK IF EVAP CANISTER SATURATED WITH WATER PBIB1387E
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
EC-1043
< SERVICE INFOMATION >
[MR TYPE 2] C
D E
F
G H
I
J
K L
M A EC
NP
O
Does water drain from
the EVAP canister?
Yes or No Yes >> GO TO 3.
No >> GO TO 6. 3.
REPLACE EVAP CANISTER
Replace EVAP canister with a new one.
>> GO TO 4. 4.
CHECK DRAIN FILTER
Refer to EC-1045, " Component Inspection " .
OK or NG OK >> GO TO 5.
NG >> Replace drain filter. 5.
DETECT MALFUNCTIONING PART
Check the EVAP hose between EVAP canister and vehicle frame for clogging or poor connection.
>> Repair or replace EVAP hose. 6.
CHECK REFUELING EVAP VAPOR CUT VALVE
Refer to EC-1045, " Component Inspection " .
OK or NG OK >>
INSPECTION END
NG >> Replace refueling EVAP vapor cut valve with fuel tank.
SYMPTOM: CANNOT REFUEL/FUEL ODOR FROM THE FUEL FILLER OPENING IS STRONG
WHILE REFUELING. 1.
CHECK EVAP CANISTER
1. Remove EVAP canister with EVAP canister vent c ontrol valve and EVAP control system pressure sensor
attached.
2. Weigh the EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor
attached.
The weight should be l ess than 1.9 kg (4.2 lb).
OK or NG OK >> GO TO 2.
NG >> GO TO 3. 2.
CHECK IF EVAP CANISTER SATURATED WITH WATER PBIB1213E
EC-1044< SERVICE INFOMATION >
[MR TYPE 2]
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
Does water drain from the EVAP canister?
Yes or No Yes >> GO TO 3.
No >> GO TO 5. 3.
REPLACE EVAP CANISTER
Replace EVAP canister with a new one.
>> GO TO 4. 4.
CHECK DRAIN FILTER
Refer to EC-1045, " Component Inspection " .
OK or NG OK >> GO TO 5.
NG >> Replace drain filter. 5.
DETECT MALFUNCTIONING PART
Check the EVAP hose between EVAP canister and vehicle frame for clogging or poor connection.
>> Repair or replace EVAP hose. 6.
CHECK VENT HOSES AND VENT TUBES
Check hoses and tubes between EVAP canister and refuel ing EVAP vapor cut valve for clogging, kink, loose-
ness and improper connection.
OK or NG OK >> GO TO 7.
NG >> Repair or replace hoses and tubes. 7.
CHECK FILLER NECK TUBE
Check recirculation line for clogging, dents and cracks.
OK or NG OK >> GO TO 8.
NG >> Replace filler neck tube. 8.
CHECK REFUELING EVAP VAPOR CUT VALVE
Refer to EC-1045, " Component Inspection " .
OK or NG OK >> GO TO 9.
NG >> Replace refueling EVAP vapor cut valve with fuel tank. 9.
CHECK FUEL FILLER TUBE
Check filler neck tube and hose connected to the fuel tank for clogging, dents and cracks.
OK or NG OK >> GO TO 10.
NG >> Replace fuel filler tube. 10.
CHECK ONE-WAY FUEL VALVE-I
Check one-way valve for clogging.
OK or NG OK >> GO TO 11. PBIB1213E
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
EC-1045
< SERVICE INFOMATION >
[MR TYPE 2] C
D E
F
G H
I
J
K L
M A EC
NP
O
NG >> Repair or replace one-way fuel valve with fuel tank. 11.
CHECK ONE-WAY FUEL VALVE-II
1. Make sure that fuel is drained from the tank.
2. Remove fuel filler tube and hose.
3. Check one-way fuel valve for operation as follows. When a stick is inserted, the valve should open, when removing
stick it should close.
Do not drop any material into the tank.
OK or NG OK >>
INSPECTION END
NG >> Replace fuel filler tube or replace one-way fuel valve with fuel tank.
Component Inspection INFOID:0000000004499920
REFUELING EVAP VAPOR CUT VALVE With CONSULT-III
1. Remove fuel tank. Refer to FL-9 .
2. Drain fuel from the tank as follows:
a. Remove fuel feed hose located on the fuel gauge retainer.
b. Connect a spare fuel hose, one side to fuel gauge retainer where the hose was removed and the other side to a fuel container.
c. Drain fuel using “FUEL PUMP RELAY” in “ACTIVE TEST” mode with CONSULT-III.
3. Check refueling EVAP vapor cut valve for being stuck to close as follows. Blow air into the refueling EVAP vapor cut valv e (from the end of EVAP/ORVR line hose), and check that
the air flows freely into the tank.
4. Check refueling EVAP vapor cut valve for being stuck to open as follows.
a. Connect vacuum pump to hose end.
b. Remove fuel gauge retainer with fuel gauge unit. Always replace O-ring with new one.
c. Put fuel tank upside down.
d. Apply vacuum pressure to hose end [ −13.3 kPa ( −100 mmHg, −3.94 inHg)] with fuel gauge retainer
remaining open and check that the pressure is applicable. SEF665U