Mitsubishi Montero (1998+). Manual — part 115
HO2S detects oxygen content in exhaust gas and sends this
information to PCM. PCM uses input signals from HO2S to vary duration
of fuel injection. HO2S heater stabilizes sensor temperature
regardless of exhaust gas temperature to allow for more accurate
exhaust oxygen content readings.
Idle Air Control (IAC) Valve Position Sensor
Sensor is incorporated in IAC motor. Sensor senses IAC motor
plunger position and sends electrical signal to PCM.
Ignition Timing Adjustment Terminal
Used for adjusting base ignition timing. When terminal is
grounded, PCM timing control function is by-passed, allowing base
timing to be adjusted.
Intake Air Temperature (IAT) Sensor
IAT sensor is incorporated into airflow sensor assembly. This
resistor-based sensor measures temperature of incoming air and
supplies air density information to PCM.
Knock Sensor (KS)
KS is located in cylinder block and senses engine vibration
during detonation (knock). KS converts vibration into electrical
signal. PCM retards ignition timing based on this signal.
Manifold Differential Pressure (MDP) Sensor
MDP sensor converts negative air pressure in intake manifold
plenum into voltage signals sent to PCM. PCM monitors Exhaust Gas
Recirculation (EGR) system using these signals.
Park/Neutral Position (PNP) Switch (Automatic Transmission)
PNP switch senses position of transmission select lever,
indicating engine load due to automatic transmission engagement. Based
on this signal, PCM commands IAC motor to increase throttle angle,
maintaining optimum idle speed.
Power Steering Oil Pressure Switch
Switch detects increase in power steering oil pressure. When
power steering oil pressure increases, switch contacts close,
signaling PCM. PCM commands IAC motor, raising idle speed to
compensate for drop in engine RPM due to power steering load.
Throttle Position (TP) Sensor
TP sensor is a variable resistor mounted on throttle body.
PCM uses voltage signal from TP sensor to determine throttle plate
angle.
Vehicle Speed Sensor (VSS)
Mounted on transaxle/transmission, VSS sends a pulsing signal
to PCM for vehicle speed calculation. PCM uses this calculation for
cruise control and fuel cut-off.
Volume Airflow (VAF) Sensor
Incorporated into airflow sensor assembly, VAF sensor
measures intake airflow rate. Intake air flows through tunnel in
airflow sensor assembly. VAF sensor sends frequency signal to PCM. PCM
uses signal to adjust fuel injection rate.
OUTPUT SIGNALS
NOTE: Vehicles are equipped with various combinations of
computer-controlled components. Not all components listed
below are used on every vehicle. To determine component
usage on specific models, see appropriate wiring diagram in
L - WIRING DIAGRAMS article. For theory and operation on each
output component, refer to system indicated after component.
Data Link Connector (DLC)
See SELF-DIAGNOSTIC SYSTEM.
EGR Control Solenoid Valve
See EXHAUST GAS RECIRCULATION (EGR) CONTROL under EMISSION
SYSTEMS.
Fuel Injectors
See FUEL CONTROL under FUEL SYSTEM.
Fuel Pressure Control Solenoid Valve (Turbo)
See FUEL DELIVERY under FUEL SYSTEM.
Fuel Pressure Regulator
See FUEL DELIVERY under FUEL SYSTEM.
Idle Air Control (IAC) Motor
See IDLE SPEED under FUEL SYSTEM.
Malfunction Indicator Light
See SELF-DIAGNOSTIC SYSTEM.
Power Transistor(s) & Ignition Coils
See IGNITION SYSTEMS.
Purge Control Solenoid Valve
See EVAPORATIVE CONTROL under EMISSION SYSTEMS.
Wastegate Control Solenoid Valve
See TURBOCHARGED ENGINES under AIR INDUCTION SYSTEM.
FUEL SYSTEM
FUEL DELIVERY
Electric fuel pump, located in gas tank, feeds fuel through
in-tank fuel filter, external fuel filter (located in engine
compartment) and fuel injector rail.
Fuel Pump
Fuel pump consists of a motor-driven impeller. Pump has an
internal check valve to maintain system pressure, and a relief valve
to protect fuel pressure circuit. Pump receives voltage supply from
MFI control relay.
Fuel Pressure Control Solenoid Valve (Turbo)
Valve prevents rough idle due to fuel percolation. On engine
restart, if engine coolant or intake air temperature reaches a preset
value, PCM applies voltage to fuel pressure control solenoid valve for
2 minutes after enginerestart. Valve will open, allowing atmospheric
pressure to be applied to fuel pressure regulator diaphragm. This
allows maximum available fuel pressure at injectors, enriching fuel
mixture and maintaining stable idle at high engine temperatures.
Fuel Pressure Regulator
Located on fuel injector rail, this diaphragm-operated relief
valve adjusts fuel pressure according to engine manifold vacuum.
As engine manifold vacuum increases (closed throttle), fuel
pressure regulator diaphragm opens relief valve, allowing pressure to
bleed off through fuel return line, reducing fuel pressure.
As engine manifold vacuum decreases (open throttle), fuel
pressure regulator diaphragm closes valve, preventing pressure from
bleeding off through fuel return line, increasing fuel pressure.
FUEL CONTROL
Fuel Injectors
Fuel is supplied to engine through electronically pulsed
(timed) injector valves located on fuel rail(s). PCM controls amount
of fuel metered through injectors based on information received from
sensors.
IDLE SPEED
Air Conditioning (A/C) Relay
When A/C is turned on with engine at idle, PCM signals IAC
motor to increase idle speed. To prevent A/C compressor from switching
on before idle speed has increased, PCM momentarily opens A/C relay
circuit.
Idle Air Control (IAC) Motor
Motor controls pintle-type air valve to regulate volume of
intake air at idle.
During start mode, PCM controls idle intake air volume
according to Engine Coolant Temperature (ECT) sensor input. After
starting, with idle position switch activated (throttle closed), fast
idle speed is controlled by IAC motor and fast idle air control valve
(if equipped).
When idle switch is deactivated (throttle open), IAC motor
moves to a preset position in accordance with ECT sensor input.
PCM signals IAC motor to increase engine RPM in the following
situations: A/T (if applicable) is shifted from Neutral to Drive, A/C
is turned on, or power steering pressure reaches a preset value.
IGNITION SYSTEMS
DIRECT IGNITION SYSTEM (DIS)
Depending on number of cylinders, ignition system is a 2 or
3-coil, distributorless ignition system. On Eclipse (Turbo) and DOHC
V6 engines, Camshaft Position (CMP) sensor is located beside camshaft,
in front of engine. On all other engines equipped with DIS, CMP sensor
is a separate unit mounted in place of distributor. On DOHC 4-
cylinder, DOHC V6 and 1.8L 4-cylinder engines with California
emissions, Crankshaft Position (CKP) sensor is located beside
crankshaft, in front of engine. PCM determines TDC based on pulse
signals received from sensors and then controls MFI and ignition
timing.
Power Transistors & Ignition Coils
Based on crankshaft position and CMP sensor inputs, PCM
controls timing and directly activates each power transistor to fire
coils. On 4-cylinder engines, power transistor "A" controls primary
current of ignition coil "A" to fire spark plugs on cylinders No. 1
and No. 4 at the same time. Power transistor "B" controls primary
current of ignition coil "B" to fire spark plugs on cylinders No. 2
and No. 3 at the same time. On V6 engines, companion cylinders No. 1
and 4, 2 and 5, and 3 and 6 are fired together.
On all models, although each coil fires 2 plugs at the same
time, ignition takes place in only one cylinder, since the other
cylinder is on its exhaust stroke when plug fires.
HALL EFFECT IGNITION SYSTEM
This system is equipped with a Hall Effect distributor.
Shutter(s) attached to distributor shaft rotate through distributor
Hall Effect switch, also referred to as a Camshaft Position (CMP)
sensor, which contains a distributor pick-up (a Hall Effect device and
magnet). As shutter blade(s) pass through pick-up, magnetic field is
interrupted and voltage is toggled between high and low. PCM uses this
data along with Crankshaft Position (CKP) sensor data to control
ignition timing and injector pulse width to maintain optimum
driveability.
Power Transistor & Ignition Coil
Power transistor is mounted inside distributor with disc and
optical sensing unit. When ignition is on, ignition coil primary
circuit is energized. As distributor shaft rotates, disc rotates,
triggering optical sensing unit. PCM receives signals from optical
sensing unit. Signals are converted and sent to power transistor,
interrupting primary current flow and inducing secondary voltage.
IGNITION TIMING CONTROL SYSTEM
Ignition timing is controlled by PCM. PCM adjusts timing
based on various conditions such as engine temperature, altitude and
detonation.
EMISSION SYSTEMS
EXHAUST GAS RECIRCULATION (EGR) CONTROL
Federal Emissions (Non-Turbo)
To lower oxides of nitrogen (NOx) exhaust emissions, a non-
computer controlled exhaust gas recirculation system is used. EGR
operation is controlled by throttle body ported vacuum. Vacuum is
routed through vacuum control valve to prevent EGR operation at low
engine temperatures.
Spring pressure holds EGR valve closed during low vacuum
conditions (engine idling or wide open throttle). When vacuum pressure
increases and overcomes EGR spring pressure, EGR valve is lifted to
allow exhaust gases to flow into intake manifold for combustion.
California Emissions & Turbo
PCM controls EGR operation by activating EGR control solenoid
valve according to engine load. When engine is cold, PCM signals EGR
control solenoid valve to deactivate EGR.
EGR Control Solenoid Valve
Valve denies or allows vacuum supply to EGR valve based on
PCM commands.
EVAPORATIVE CONTROL
Fuel evaporation system prevents fuel vapor from entering
atmosphere. System consists of special fuel tank with vapor separator
tanks (if equipped), vacuum relief filler cap, overfill limiter (2-way
valve), fuel check valve, thermovalve (if equipped), charcoal
canister, purge control valve, purge control solenoid valve, and
connecting lines and hoses.
Purge Control Solenoid Valve
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст