Lexus RX300 (MCU15). Service manual — part 42

EG

ENGINE — 1MZ-FE ENGINE

Torque Rod

Liquid-Filled
Compound
Mount

VSV

Active Control
Engine Mount

Absorber

Left Mount

187EG40

41

JENGINE MOUNT

1. General

A 3-point support on the front subframe has been
adopted. An active control engine mount has been
adopted for the front engine mount and a liquid-filled
compound mount has been adopted for the rear en-
gine mount to reduce noise and vibration and to
achieve high levels of both riding comfort and driv-
ability.

2. Active Control Engine Mount

The operating range of the active control engine mount is during idling under the engine speeds of 900
rpm. Signals that are synchronized to the engine rpm (number of combustions) are sent by the engine
ECU to the VSV and the engine vacuum is utilize to vary the pressure of the intake air chamber in the
active control engine mount. As a result, the diaphragm vibrates, and using the liquid as a medium, the
rubber mount vibrates. This vibration of the engine mount acts to cancel out the engine vibration during
idle, thus reducing the vibration and noise at idle.
The engine mount’s force to generate vibrations is adjusted through the effects of the orifice and the side
branch.

Active Control
Engine Mount

Intake Air
Chamber

Engine
ECU

161ES47

VSV

Engine

Main Liquid
Chamber

Rubber

Side Branch

Vacuum
Tank

Orifice

To
VSV

161ES46

Diaphragm

Air
Chamber

Rubber

ENGINE — 1MZ-FE ENGINE

42

JENGINE CONTROL SYSTEM

1. General

The engine control system for the 1MZ-FE engine has following system.

System

Outline

EFI

Electronic Fuel
Injection

D An L-type EFI system directry detects the intake air volume with a hot-

wire type air flow meter.

D The fuel injection is a sequential multiport fuel injection system.

ESA

Electronic Spark
Advance

D Ignition timing is determined by the engine ECU based on signals from

various sensors. Corrects ignition timing in response to engine knocking.

D The torque control correction during automatic transmission gear shift-

ing has been used to minimize the shift shock.

D 2 knock sensors are used to improve knock detection.

ISC
(Idle Speed Control)

A rotary solenoid type ISC valve controls the fast idle and idle speed.

VVT-i

Variable Valve
Timing-intelligent

Controls the intake camshaft to an optimal valve timing in accordance with
the engine condition.

ACIS

Acoustic Control
Induction System

The intake air passages are switched according to the engine speed and
throttle valve opening angle to provide high performance in all speed ranges.

Fuel Pump Control

D Fuel pump operation is controlled by signal from the engine ECU.

D A fuel cut control is adopted to stop the fuel pump when the SRS airbag

is deployed.

Air Fuel Ratio Sensor
Heater Control

Maintains the temperature of the air fuel ratio sensor at an appropriate level
to increase accuracy of detection of the oxygen concentration in the exhaust
gas.

Oxygen Sensor
Heater Control

Maintains the temperature of the oxygen sensor at an appropriate level to
increase accuracy of detecion of the oxygen concentration in the exhaust
gas.

Air Conditioning
Cut-off Control

By turning the air conditioning compressor ON or OFF in accordance with
the engine condition, drivability is maintained.

Evaporative Emission
Control

The engine ECU controls the purge flow of evaporative emissions (HC) in
the charcoal conister in accordance with engine conditions.

Engine Immobilizer

Prohibits fuel delivery and ignition if an attempt is made to start the engine
with an invalid ignition key.

Function to communicate
with multiplex commu-
nication system

Communicates with the body ECU, A/C ECU, meter ECU, etc., on the body
side, to input/output necessary signals.

Active Control
Engine Mount

The spring characteristic of the front engine mount is controlled variablly
to reduce idling vibration.

Diagnosis

When the engine ECU detects a malfunction, the engine ECU diagnoses and
memorizes the failed section.

Fail-safe

When the engine ECU detects a malfunction, the engine ECU stops or con-
trols the engine according to the data already stored in the memory.

ENGINE — 1MZ-FE ENGINE

EG

#10

#20

#30

#40

IGT1~

IGT6

IGF

RSO

OC1

FC

HAFL

MREL

NSW

Engine

ECU

R, D, 2, L

KNKR

KNKL

OXS

AFL

AFR

SPD

STA

IGSW

VTA1

VC

THW

VV1

VV2

THA

NE

VG

#50

#60

OC2

ACIS

ACI1

HAFR

43

2. Construction

The configuration of the engine control system in the 1MZ-FE engine is shown in the following chart.

SENSORS

AIR FLOW METER

INTAKE AIR TEMP. SENSOR

CRANKSHAFT POSITION

SENSOR

VVT SENSOR

• Camshaft Angle Signal

WATER TEMP. SENSOR

THROTTLE POSITION SENSOR

IGNITION SWITCH

• Starting Signal

• Ignition Signal

COMBINATION METER

• Vehicle Speed Signal

AIR FUEL RATIO SENSOR

(Bank 1, Sensor 1)

AIR FUEL RATIO SENSOR

(Bank 2, Sensor 1)

HEATED OXYGEN SENSOR

(Bank 1, Sensor 2)

KNOCK SENSOR

NEUTRAL START SWITCH

• Neutral Start Signal

• Shift Lever Position Signal

ACTUATORS

EFI

No. 1 INJECTOR

No. 2 INJECTOR

No. 3 INJECTOR

No. 4 INJECTOR

No. 5 INJECTOR

No. 6 INJECTOR

ESA

IGNITION COIL with IGNITER

SPARK PLUGS

VVT-i

CAMSHAFT TIMING OIL

CONTROL VALVE

ISC

CONTROL VALVE

ACIS

VSVs

FUEL PUMP CONTROL

CIRCUIT OPENING RELAY

AIR FUEL RATIO SENSOR

HEATER CONTROL

AIR FUEL RATIO SENSOR

HEATER (Bank 1, Sensor 1)

AIR FUEL RATIO SENSOR

HEATER (Bank 2, Sensor 1)

AIR FUEL RATIO SENSOR

HEATER RELAY

EFI MAIN RELAY

(Continued)

ENGINE — 1MZ-FE ENGINE

*: Only LHD models for Europe

BATT

+B

BATTERY

EFI MAIN RELAY

ACM1

MPX1

MPX2

TACH

SNOW

MOPS

F/PS

CF

PS

THO

STP

KD

TRC

ENG

TXCT

RXCK

CODE

KSW

RL

SIL

TC

W

IMLD

EVP1

HTS

OD1

IDLO

ACMG

44

AIR CONDITIONER ECU

BODY ECU

SNOW SWITCH

METER ECU

ENGINE OIL PRESSURE

SWITCH

AIRBAG SENSOR ASSEMBLY

COOLING FAN RELAY

POWER STEERING OIL

PRESSURE SWITCH

A/T FLUID TEMPERATURE SENSOR

STOP LIGHT SWITCH

KICK DOWN SWITCH*

SKID CONTROL ECU

TRANSPONDER KEY

AMPLIFIER

UNLOCK WARNING SWITCH

ALTERNATOR

DATA LINK CONNECTOR 3

CRUISE CONTROL ECU

AIR CONDITIONER

CONTROL

AIR CONDITIONER

MAGNET CLUTCH

OXYGEN SENSSOR HEATER

CONTROL

HEATED OXYGEN SENSOR

HEATER (Bank 1, Sensor 2)

ACTIVE CONTROL ENGINE

MOUNT

VSV

EVAP CONTROL

VSV (for EVAP)

SECURITY

INDICATOR LIGHT

CHECK ENGINE WARNING

LIGHT