1999 NISSAN PRIMERA Control

Vacuum Hose DrawingNCEC0012Refer to ªSystem Diagramº on EC-QG-18 for vacuum control system.
NEF231A Fuel pressure
regulator
EVAP canister purge
pipe (to EVAP
canister)
To air duct To air control valve
(Power steering)
EVAP canister purge volume
control solenoid valve
EVAP canister
Air
Fuel tank
ENGINE AND EMISSION CONTROL OVERALL SYSTEMQG16I18DE
Vacuum Hose Drawing
EC-19

System ChartNCEC0013
Input (Sensor) ECM Function Output (Actuator)
ICamshaft position sensor (PHASE)
IMass air flow sensor
IEngine coolant temperature sensor
IHeated oxygen sensor 1 (front)
IIgnition switch
IThrottle position sensor
IPNP switch
IAir conditioner switch
IKnock sensor
IEGR temperature sensor*1*3
ICrankshaft position sensor (POS)
IBattery voltage
IPower steering oil pressure switch
IVehicle speed sensor or ABS actuator and
electric unit (control unit)
IIntake air temperature sensor
IHeated oxygen sensor 2 (rear)*2
IElectrical load
IRefrigerant pressure sensorFuel injection & mixture ratio control Injectors
Electronic ignition system Power transistor
Idle air control system IACV-AAC valve
Valve timing controlIntake valve timing control sole-
noid valve
Fuel pump control Fuel pump relay
Heated oxygen sensor 1 monitor & on
board diagnostic systemMalfunction indicator
(On the instrument panel)
EGR control*3 EGR volume control valve*3
Heated oxygen sensor 1, 2 heater control Heated oxygen sensor heater
EVAP canister purge flow controlEVAP canister purge volume con-
trol solenoid valve
Cooling fan control Cooling fan relay
Air conditioning cut control Air conditioner relay
*1: This sensor is not used to control the engine system. They are used only for the on board diagnosis.
*2: Under normal conditions, this sensor is not for engine control operation.
*3: If so equipped
ENGINE AND EMISSION CONTROL OVERALL SYSTEMQG16I18DE
System Chart
EC-20

Multiport Fuel Injection (MFI) System
DESCRIPTIONNCEC0014Input/Output Signal ChartNCEC0014S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed and piston position
Fuel injec-
tion & mix-
ture ratio
controlInjector Camshaft position sensor (PHASE) Cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Heated oxygen sensor 1 (front) Density of oxygen in exhaust gas
Throttle position sensorThrottle position
Throttle valve idle position
PNP switch Gear position
Vehicle speed sensor or ABS actuator and
electric unit (control unit)Vehicle speed
Ignition switch Start signal
Air conditioner switch Air conditioner operation
Knock sensor Engine knocking condition
Electrical load Electrical load signal
Battery Battery voltage
Power steering oil pressure switch Power steering operation
Heated oxygen sensor 2 (rear)* Density of oxygen in exhaust gas
* Under normal conditions, this sensor is not for engine control operation.
Basic Multiport Fuel Injection SystemNCEC0014S02The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from both the camshaft position sensor and the mass air
flow sensor.
Various Fuel Injection Increase/Decrease CompensationNCEC0014S03In addition, the amount of fuel injected is compensated to improve engine performance under various oper-
ating conditions as listed below.

IDuring warm-up
IWhen starting the engine
IDuring acceleration
IHot-engine operation
IHigh-load, high-speed operation

IDuring deceleration
IDuring high engine speed operation
IDuring high vehicle speed operation (M/T models)
IExtremely high engine coolant temperature
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONQG16I18DE
Multiport Fuel Injection (MFI) System
EC-21

Mixture Ratio Feedback Control (Closed loop control)NCEC0014S04
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission con-
trol. The three way catalyst can then better reduce CO, HC and NOx emissions. This system uses a heated
oxygen sensor 1 (front) in the exhaust manifold to monitor if the engine operation is rich or lean. The ECM
adjusts the injection pulse width according to the sensor voltage signal. For more information about the heated
oxygen sensor 1 (front), refer to EC-QG-132. This maintains the mixture ratio within the range of stoichiomet-
ric (ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 (rear) is located downstream of the three way catalyst. Even if the switching char-
acteristics of the heated oxygen sensor 1 (front) shift, the air-fuel ratio is controlled to stoichiometric by the
signal from the heated oxygen sensor 2 (rear).
Open Loop ControlNCEC0014S05The 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.
IDeceleration and acceleration
IHigh-load, high-speed operation
IMalfunction of heated oxygen sensor 1 (front) or its circuit
IInsufficient activation of heated oxygen sensor 1 (front) at low engine coolant temperature
IHigh engine coolant temperature
IDuring warm-up
IWhen starting the engine
Mixture Ratio Self-learning ControlNCEC0014S06The mixture ratio feedback control system monitors the mixture ratio signal transmitted from the heated oxy-
gen sensor 1 (front). 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 basic mixture ratio is not necessarily con-
trolled as originally designed. Both manufacturing differences (i.e., mass air flow sensor hot film) and charac-
teristic changes during operation (i.e., 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 ªinjection pulse durationº to automatically compensate for the difference between
the two ratios.
ªFuel trimº refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
ªShort term fuel trimº is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from the heated oxygen sensor 1 (front) indicates whether the mixture ratio is RICH or LEAN
compared to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is
rich, and an increase in fuel volume if it is lean.
ªLong term fuel trimº is overall fuel compensation carried 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.
SEF336WA
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONQG16I18DE
Multiport Fuel Injection (MFI) System (Cont'd)
EC-22

Fuel Injection TimingNCEC0014S07
Two types of systems are used.
Sequential Multiport Fuel Injection System
NCEC0014S0701Fuel is injected into each cylinder during each engine cycle according to the firing order. This system is used
when the engine is running.
Simultaneous Multiport Fuel Injection System
NCEC0014S0702Fuel 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 injectors will then receive the signals two times for each engine cycle.
This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
Fuel Shut-offNCEC0014S08Fuel to each cylinder is cut off during deceleration or operation of the engine at excessively high speeds.
Electronic Ignition (EI) System
DESCRIPTIONNCEC0015Input/Output Signal ChartNCEC0015S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed and piston position
Ignition tim-
ing controlPower transistor Camshaft position sensor (PHASE) Cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensorThrottle position
Throttle valve idle position
Vehicle speed sensor or ABS actuator and
electric unit (control unit)Vehicle speed
Ignition switch Start signal
Knock sensor Engine knocking
PNP switch Gear position
Battery Battery voltage
SEF337W
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONQG16I18DE
Multiport Fuel Injection (MFI) System (Cont'd)
EC-23

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, crankshaft position sensor signal and cam-
shaft position sensor signal. Computing this information, ignition signals are transmitted to the power transis-
tor.
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
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 Throttle position sensor Throttle valve opening angle
Crankshaft position sensor (POS) 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.
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.
SEF742M
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONQG16I18DE
Electronic Ignition (EI) System (Cont'd)
EC-24

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
Crankshaft position sensor (POS) 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-QG-21.
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
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 also shuts off the vapor purge line during decelerating and
idling.
SEF916WA
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONQG16I18DE
Fuel Cut Control (at no load & high engine speed)
EC-25

INSPECTIONNCEC0019EVAP CanisterNCEC0019S01Check EVAP canister as follows:
1. Block port B. Orally blow air through port A. Check that air
flows freely through port C with check valve resistance.
2. Block port A. Orally blow air through port B. Check that air
flows freely through port C.
Fuel Tank Vacuum Relief Valve (Built into fuel filler cap)NCEC0019S031. Wipe clean valve housing.
2. Check valve opening pressure and vacuum.
Pressure:
16.0 - 20.0 kPa (0.16 - 0.20 bar, 0.163 - 0.204
kg/cm
2, 2.32 - 2.90 psi)
Vacuum:
þ6.0 to þ3.5 kPa (þ0.060 to þ0.035 bar, þ0.061 to
þ0.036 kg/cm
2, þ0.87 to þ0.51 psi)
3. If out of specification, replace fuel filler cap as an assembly.
Evaporative Emission (EVAP) Canister Purge Volume
Control Solenoid Valve
NCEC0019S07Refer to EC-QG-266.
SEF917W
SEF918W
SEF943S
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTIONQG16I18DE
Evaporative Emission System (Cont'd)
EC-26