System DescriptionNCEC0015S02
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of
the engine. The ignition timing data is stored in the ECM. This data forms the map shown above.
The ECM receives information such as the injection pulse width and camshaft position sensor signal. Com-
puting this information, ignition signals are transmitted to the power transistor.
e.g., N: 1,800 rpm, Tp: 1.50 msec
AÉBTDC
During the following conditions, the ignition timing is revised by the ECM according to the other data stored
in the ECM.
IAt starting
IDuring warm-up
IAt idle
IAt low battery voltage
IDuring acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions.
If engine knocking occurs, the knock sensor monitors the condition. The signal is transmitted to the ECM. The
ECM retards the ignition timing to eliminate the knocking condition.
Air Conditioning Cut Control
DESCRIPTIONNCEC0016Input/Output Signal ChartNCEC0016S01
Sensor Input Signal to ECMECM func-
tionActuator
Air conditioner switch Air conditioner ªONº signal
Air condi-
tioner cut
controlAir conditioner relay PNP switch Neutral position
Throttle position sensor Throttle valve opening angle
Camshaft position sensor Engine speed
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Refrigerant pressure sensor Refrigerant pressure
Vehicle speed sensor or ABS actuator and
electric unit (control unit)Vehicle speed
Power steering oil pressure switch Power steering operation
System DescriptionNCEC0016S02This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.
IWhen the accelerator pedal is fully depressed.
IWhen cranking the engine.
SEF742M
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONSR20DE
Distributor Ignition (DI) System (Cont'd)
EC-26
IAt high engine speeds.
IWhen the engine coolant temperature becomes excessively high.
IWhen operating power steering during low engine speed or low vehicle speed.
IWhen engine speed is excessively low.
Fuel Cut Control (at no load & high engine
speed)
DESCRIPTIONNCEC0017Input/Output Signal ChartNCEC0017S01
Sensor Input Signal to ECMECM func-
tionActuator
Vehicle speed sensor or ABS actuator and
electric unit (control unit)Vehicle speed
Fuel cut
controlInjectors PNP switch Neutral position
Throttle position sensor Throttle position
Engine coolant temperature sensor Engine coolant temperature
Camshaft position sensor Engine speed
If the engine speed is above 3,950 rpm with no load, (for example, in Neutral and engine speed over 4,000
rpm) fuel will be cut off after some time. The exact time when the fuel is cut off varies based on engine speed.
Fuel cut will operate until the engine speed reaches 1,150 rpm, then fuel cut is cancelled.
NOTE:
This function is different from deceleration control listed under ªMultiport Fuel Injection (MFI) Systemº,
EC-SR-23.
Evaporative Emission System
DESCRIPTIONNCEC0018
The evaporative emission system is used to reduce hydrocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplished by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into the EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not operating 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 control solenoid valve is controlled by ECM. When the engine operates, the flow
Intake manifold
Throttle body
Purge line
EVAP canister
purge volume
control solenoid
valve
Relief of vacuum
Sealing gas cap with
pressure relief valve
and vacuum relief
valve
Fuel tankAir
Fuel vapor EVAP
canister
SEF916W
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONSR20DE
Air Conditioning Cut Control (Cont'd)
EC-27
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment
NCEC0028PREPARATIONNCEC0028S01IMake sure that the following parts are in good order.
a)Battery
b)Ignition system
c)Engine oil and coolant levels
d)Fuses
e)ECM harness connector
f)Vacuum hoses
g)Air intake system
(Oil filler cap, oil level gauge, etc.)
h)Fuel pressure
i)Engine compression
j)Throttle valve
k)EVAP system
IOn models equipped with air conditioner, checks should
be carried out while the air conditioner is ªOFFº.
IWhen checking idle speed on models equipped with CVT,
ignition timing and mixture ratio, checks should be carried
out while shift lever is in ªPº or ªNº position.
IWhen measuring ªCOº percentage, insert probe more
than 40 cm (15.7 in) into tail pipe.
ITurn off headlamps, heater blower, rear window defogger.
IOn vehicles equipped with daytime running light systems,
set lighting switch to the 1st position to light only small
lamps.
IKeep front wheels pointed straight ahead.
IIf engine stops immediately after starting or idle condition
is unstable, perform the following to initialize IACV-AAC
valve:
a)Stop engine and wait 9 seconds.
b)Turn ignition ªONº and wait 1 second.
c)Turn ignition ªOFFº and wait 9 seconds.
IMake the check after the cooling fan has stopped.
BASIC SERVICE PROCEDURESR20DE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment
EC-34
INSPECTION PROCEDURENCEC0028S02
1 INSPECTION START
1. Visually check the following:
IAir cleaner clogging
IHoses and duct for leaks
IElectrical connectors
IGasket (intake manifold, cylinder head, exhaust system)
IThrottle valve and throttle position sensor operation
2. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
Ensure engine speed stays below 1,000 rpm.
SEF935W3. Open engine hood and run engine at about 2,000 rpm for about 2 minutes under no-load.
4. Perform the Diagnostic Test Mode II (Self-diagnostic results). Refer to EC-SR-61.
SAT652J
OK or NG
OK©IGO TO 2. (With CONSULT-II)
IGO TO 3. (Without CONSULT-II)
NG©1. Repair or replace components as necessary.
2. GO TO 2. (With CONSULT-II)
3. GO TO 3. (Without CONSULT-II)
BASIC SERVICE PROCEDURESR20DE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-36
10 PREPARATION FOR ªCOº % CHECK
With CONSULT-II
1. Connect ECM harness connector to ECM.
2. Connect battery ground cable.
3. Select ªENGINE COOLANT TEMPº in ªACTIVE TESTº mode.
4. Set ªCOOLANT TEMPº to 5ÉC (41ÉF) by touching ªQuº and ªQdº and ªUPº, ªDOWNº.
NEF061A
Without CONSULT-II
1. Connect ECM harness connector to ECM.
2. Disconnect engine coolant temperature sensor harness connector.
3. Connect a resistor (4.4 kW) between terminals of engine coolant temperature sensor harness connector.
SEF053RA4. Connect battery ground cable.
©GO TO 11.
Engine coolant
temperature sensor
harness connector
4.4 kWresistor
BASIC SERVICE PROCEDURESR20DE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-43
11 CHECK ªCOº %
1. Start engine and warm it up until engine coolant temperature indicator points to middle of gauge.
(Be sure to start engine after setting ªCOOLANT TEMPº or installing a 4.4 kWresistor.)
SEF935W2. Rev engine two or three times under no-load, then run engine at idle speed.
SEF978U3. Check ªCOº%.
Idle CO: Less than 11% and engine runs smoothly.
4.
Without CONSULT-II
After checking CO%, stop engine and
a. Disconnect the resistor from terminals of engine coolant temperature sensor harness connector.
b. Connect engine coolant temperature sensor harness connector to engine coolant temperature sensor.
OK or NG
OK©GO TO 12.
NG©GO TO 13.
12 CHECK HEATED OXYGEN SENSOR 1 (FRONT) SIGNAL
With CONSULT-II
1. Replace heated oxygen sensor 1 (front).
2. See ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode.
3. Maintain engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.). Check that the monitor fluctu-
ates between ªLEANº and ªRICHº more than five times during 10 seconds.
1 cycle: RICH®LEAN®RICH
2 cycles: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Replace heated oxygen sensor 1 (front).
2. Set ªHeated oxygen sensor 1 (front) monitorº in the Diagnostic Test Mode II.
(See page EC-SR-61.)
3. Maintain engine at 2,000 rpm under no-load. Check that the malfunction indicator goes on and off more than five times during 10 sec-
onds.
OK or NG
OK©GO TO 5. (With CONSULT-II)
GO TO 6. (Without CONSULT-II)
NG©GO TO 13.
BASIC SERVICE PROCEDURESR20DE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-44
13 DETECT MALFUNCTIONING PART
1. Connect heated oxygen sensor 1 (front) harness connector to heated oxygen sensor 1 (front).
2. Check fuel pressure regulator. Refer to EC-SR-32.
3. Check mass air flow sensor and its circuit.
Refer to EC-SR-120.
4. Check injector and its circuit.
Refer to EC-SR-302.
Clean or replace if necessary.
5. Check engine coolant temperature sensor and its circuit. Refer to EC-SR-132.
6. Check ECM function by substituting another known good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 5. (With CONSULT-II)
GO TO 6. (Without CONSULT-II)
IIf a vehicle contains a part which is operating outside of
design specifications with no MI illumination, the part
shall not be replaced prior to emission testing unless it is
determined that the part has been tampered with or
abused in such a way that the diagnostic system cannot
reasonably be expected to detect the resulting malfunc-
tion.
BASIC SERVICE PROCEDURESR20DE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-45
Idle Air Volume LearningNCEC0541DESCRIPTIONNCEC0541S01ªIdle Air Volume Learningº is an operation to learn the idle air vol-
ume that keeps each engine within the specific range. It must be
performed under any of the following conditions:
IEach time IACV-AAC valve, throttle body or ECM is replaced.
IIdle speed or ignition timing is out of specification.
PRE-CONDITIONINGNCEC0541S04Before performing ªIdle Air Volume Learningº, make sure that all of
the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are
missed for even a moment.
IBattery voltage: More than 12.9V (At idle)
IEngine coolant temperature: 70 - 94ÉC (158 - 201ÉF)
IPNP switch: ON
IElectric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime running light systems, set
lighting switch to the 1st position to light only small lamps.
ICooling fan motor: Not operating
ISteering wheel: Neutral (Straight-ahead position)
IVehicle speed: Stopped
ITransmission : Warmed up
For CVT models with CONSULT-II, drive vehicle until ªFLUID
TEMP SEº in ªDATA MONITORº mode of ªCVTº system indi-
cates less than 0.9V.
For CVT models without CONSULT-II and M/T models, drive
vehicle for 10 minutes.
OPERATION PROCEDURENCEC0541S02With CONSULT-IINCEC0541S02011. Start engine and warm it up to normal operating temperature.
2. Check that all items listed under the topic ªPre-Conditioningº
(previously mentioned) are in good order.
3. Turn ignition switch ªOFFº and wait at least 9 seconds.
4. Start the engine and allow it to idle for at least 28 seconds.
5. Select ªIDLE AIR VOL LEARNº in ªWORK SUPPORTº mode.
6. Touch ªSTARTº and wait 20 seconds.
7. Make sure that ªCMPLTº is displayed on CONSULT-II screen.
If ªINCMPº is displayed, ªIdle Air Volume Learningº will not be
carried out successfully. In this case, find the cause of the
problem by referring to the NOTE below.
8. Rev up the engine two or three times. Make sure that idle
speed and ignition timing are within specifications.
ITEM SPECIFICATION
Idle speed750 50rpm (in ªPº or ªNº position for CVT)
Ignition timing15 2É BTDC
SEF712X
SEF713X
SEF714X
BASIC SERVICE PROCEDURESR20DE
Idle Air Volume Learning
EC-46