1991 LEXUS SC400 oil temperature

OKNG
OKNG
5Check idle speed.
C
OK
P(1) Warm up engine at normal operating temperature.
(2) Switched off all accessories.
(3) Switched off air conditioner.
(4) Shift transmission into ªNº range.
(5) Connect tachometer test probe to terminal IG
of
check connector, and set the tachometer to the
4±cylinder range.
Check idle speed.
Idle speed: 650 ~ 750 rpm
Caution:

NEVER allow tachometer test probe to touch
ground as it could result in damage to igniter
and/or coil.

As some tachometers are not compatible with
this ignition system, we recommended that you
confirm compatibility of your unit before use.
Proceed to matrix chart of problem symptoms on page
TR±35 .
6Check ignition timing.
C
OK
P(1) Warm up engine at normal operating temperture.
(2) Shift transmission into ªNº range.
(3) Keep the engine speed at idle.
(4) Using SST, connect terminals TE1 and E1 of check
connector.
SST 09843±18020
(5) Using a timing light. connect the tester to No. 6 high±tension cord.
Check ignition timing.
Ignition Timing: 8±12  BTDC at idle
Proceed to page IG±28 and continue to troubleshoot.
Proceed to matix chart of problem symptoms on
page TR±35 .
±
ENGINE TROUBLESHOOTING Basic InspectionTR±25
WhereEverybodyKnowsYourName

Cold Start Injector Circuit
CIRCUIT DESCRIPTION
The cold start injector is used to maintain the engine startability when it\
is cold. The injection volume, i,e, the
length of time the injector is energized, is controlled by the ECU and t\
he cold start injector time switch.
During a cold start, when the starter turns the contacts in the cold start inj\
ector time switch close. Thus current
flows to the cold start injector coil, injecting fuel. At the same time, a bi\
metal in the heat coil is energized and
heats up. This soon causes the contacts to open, cutting off the current flow to the injector coil and stopping
fuel injection.
The injection duration of the cold start injector is determined by the cool\
ant temperature and the length of time
current flows to the heat coil. When the engine is warm, the contacts are opened by the bimetal and the cold
start injector does not operate.
When the engine is hard to start and the starter is operated continuously, heat coil (2) heats up the bimetal keep-
ing the contacts open to prevent spark plugs from becoming fouled, which is\
caused by the cold start injector
operation when the open contacts close again.
When the engine is started at a coolant temperature of 225C (72 5F) or lower, the cold start injector operation
time is controlled by the cold start injector time switch.
When the coolant temperature is in the normal temperature range 22 5C (72 5F) or higher, the contacts of the cold
start injector time switch are open and the time switch is off, instead, the ECU controls the operating time of the
cold start injector.
In this way, the CO and HC levels can be reduced while the engine is being started \
and the engine startability
is maintained. Control by the ECU ends when the coolant temperature reac\
hes 60 5C (140 5F).
TR±136±
ENGINE TROUBLESHOOTING Circuit Inspection
WhereEverybodyKnowsYourName

OKNG
OKNG
5Check idle speed.
C
OK
P(1) Warm up engine at normal operating temperature.
(2) Switched off all accessories.
(3) Switched off air conditioner.
(4) Shift transmission into ªNº range.
(5) Connect tachometer test probe to terminal IG
of
check connector, and set the tachometer to the
4±cylinder range.
Check idle speed.
Idle speed: 650 ~ 750 rpm
Caution:

NEVER allow tachometer test probe to touch
ground as it could result in damage to igniter
and/or coil.

As some tachometers are not compatible with
this ignition system, we recommended that you
confirm compatibility of your unit before use.
Proceed to matrix chart of problem symptoms on page
TR±35 .
6Check ignition timing.
C
OK
P(1) Warm up engine at normal operating temperture.
(2) Shift transmission into ªNº range.
(3) Keep the engine speed at idle.
(4) Using SST, connect terminals TE1 and E1 of check
connector.
SST 09843±18020
(5) Using a timing light. connect the tester to No. 6 high±tension cord.
Check ignition timing.
Ignition Timing: 8±12  BTDC at idle
Proceed to page IG±28 and continue to troubleshoot.
Proceed to matix chart of problem symptoms on
page TR±35 .
±
ENGINE TROUBLESHOOTING Basic InspectionTR±25
WhereEverybodyKnowsYourName

17
1. NORMALLYOPENOpens and
closes circuits,
thereby
stopping (1) or
allowing (2)
current flow.
RESISTOR An electrical component with a
fixed resistance, placed in a circuit
to reduce voltage to a specific
value.
RESISTOR, TAPPED A resistor which supplies two or
more different non±adjustable
resistance values.
SENSOR (Thermistor) A resistor which varies its
resistance with temperature.
SHORT PIN Used to provide an unbroken
connection within a junction block.
SOLENOID An electromagnetic coil which
forms a magnetic field when
current flows, to move a plunger,
etc. SWITCH, DOUBLE THROW
A switch which continuously
passes current through one set
of contacts or the other.
SWITCH,
IGNITION A key operated switch with
several positions which allows
various circuits, particularly the
primary ignition circuit, to
become operational.
Wires are always
drawn as straight lines
on wiring diagrams.
Crossed wires (1)
without a black dot at
the junction are not
joined; crossed wires
(2) with a black dot or
octagonal (
) mark at
the junction are spliced
(joined) connections.
RELAY, DOUBLE THROW
A relay which passes current
through one set of contacts or the
other.
SENSOR, ANALOG SPEED Uses magnetic impulses to open
and close a switch to create a
signal for activation of other
components. TRANSISTOR
A solidstate device typically used
as an electronic relay; stops or
passes current depending on the
voltage applied at ªbase.º
SWITCH, WIPER PARK
Automatically returns wipers to
the stop position when the wiper
switch is turned off.
SWITCH, MANUAL SPEAKER
An electromechanical device
which creates sound waves from
current flow.
2. NORMALLY CLOSED
RESISTOR, VARIABLE OR
RHEOSTAT A controllable resistor with a
variable rate of resistance.
Also called a potentiometer or
rheostat.
2. NORMALLY
OPEN
RELAY
1. NORMALLY
CLOSED Basically, an electrically
operated switch which may
be normally closed (1) or
open (2).
Current flow through a
small coil creates a
magnetic field which either
opens or closes an
attached switch.
(2) SPLICEDWIRES
(1) NOT CONNECTED
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