1991 LEXUS SC300 oil

ON±VEHICLE INSPECTION
SPARK TEST
CHECK THAT SPARK OCCURS(a) Remove the No.3 timing belt covers.(See steps 2 to 8 on pages IG±11 to 13)
(b) Disconnect the high±tension cords (from the ignition
coils) from the distributor caps.
(c) Hold the end about 12.5 mm (0.50 in.) from the body ground.
(d) Check if spark occurs while engine is being cranked.
HINT: To prevent gasoline from being injected from injectors
during this test, crank the engine for no more than 1±2 se-
conds at a time.
If the spark does not occur, perform the test as follows:
(e) Reconnect the high±tension cords to the distributor caps.
(f) Reinstall the No.3 timing belt covers. (See steps 5 to 11 on pages IG±17 to 19)
IG±6
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IGNITION SYSTEM On±Vehicle Inspection
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4. VISUALLY INSPECT SPARK PLUGSCheck the spark plug for thread damage and insulator dam-
age.
If abnormal, replace the spark plug.
Recommended spark plug: ND PK20R11
NGK BKR6EP11
5. INSPECT ELECTRODE GAP
Maximum electrode gap: 1.3 mm (0.051 in.)
If the gap is greater than maximum, replace the spark plug.
Correct electrode gap of new spark plug:1.1 mm (0.043 in.)
NOTICE: If adjusting the gap of a new spark plug, bent
only the base of the ground electrode. Do not touch the
tip. Never attempt to adjust the gap on the used plug.
6. CLEAN SPARK PLUGS If the electrode has traces of wet carbon, allow it to dry and
then clean with a spark plug cleaner.
Air pressure: Below 588 kPa (6 kgf/cm2, 85 psi)
Duration: 20 seconds or less
HINT: If there are traces of oil, remove it with gasoline before
using the spark plug cleaner.
7. REINSTALL SPARK PLUGS Using a 16 mm plug wrench, install the spark plug.
Torque: 18 N Vm (180 kgf Vcm, 13 ft Vlbf)
8. RECONNECT HIGH±TENSION CORDS TO SPARK
PLUGS
(See steps 4 to 13 on pages IG±16 to 19)
IG±8
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IGNITION SYSTEM On±Vehicle Inspection
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INSPECTION OF IGNITION COIL
1. (RH IGNITION COIL)REMOVE IGNITION COIL (See page IG±21)
2. (LH IGNITION COIL)
DISCONNECT IGNITION COIL CONNECTOR AND HIGH±
TENSION CORD FROM IGNITION COIL
3. INSPECT PRIMARY COIL RESISTANCE Using an ohmmeter, measure the resistance between posi-
tive (+) and negative (±) terminals.
Primary coil resistance (Cold): 0.40±0.50

If the resistance is not as specified, replace the ignition coil.
4. INSPECT SECONDARY COIL RESISTANCE Using an ohmmeter, measure the resistance between posi-
tive (+) and high±tension terminals.
Secondary coil resistance (Cold): 10.0±14.0 k

If the resistance is not as specified, replace the ignition coil.
5. (RH IGNITION COIL) REINSTALL IGNITION COIL (See page IG±22)
6. (LH IGNITION COIL) RECONNECT IGNITION COIL CONNECTOR AND HIGH±
TENSION CORD FROM IGNITION COIL
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IGNITION SYSTEM On±Vehicle InspectionIG±9
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INSPECTION OF CAM POSITION
SENSORS
1. DISCONNECT CAM POSITION SENSOR CONNECTORS(a) (RH Cam Position Sensor)Disconnect the cam position sensor connector from the
ignition coil bracket.
(See steps 5 (a) on page IG±24)
(b) Disconnect the cam position sensor connectors.
2. INSPECT CAM POSITION SENSOR RESISTANCE Using an ohmmeter, measure the resistance between termi-
nals.
Resistance (Cold):
835±1,350
at ±10± +40 5C (14±104 5F)
If the resistance is not as specified, replace the cam position
sensor.
3. RECONNECT CAM POSITION SENSOR CONNECTORS
INSPECTION OF ENGINE SPEED
SENSOR
1. REMOVE ENGINE SPEED SENSOR (See page IG±30)
2. INSPECT ENGINE SPEED SENSOR RESISTANCE Using an ohmmeter, measure the resistance between termi-
nals.
Resistance (Cold):
835±1,350
at ±10± +40 5C (14±104 5F)
If the resistance is not as specified, replace the engine speed
sensor.
3. REINSTALL ENGINE SPEED SENSOR (See page IG±30)
INSPECTION OF ENGINE SPEED
SENSOR
(See procedure Spark Test on page IG±6)
IG±10
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IGNITION SYSTEM On±Vehicle Inspection
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(b) Disconnect the high±tension cords from the ignitioncoils.
w Using a screwdriver, lift up the lock claw and
disconnect the holder from the ignition coil.
w Disconnect the high±tension cord at the grommet.
Do not pull on the cord.
NOTICE: Pulling on or bending the cords may damage
the conductor inside.
(c) Disc onnect the high±tension cords from the cord
clamps and lower high±tension cord cover, and remove
the ten high±tension cords.
(d) Remove the five cords clamp from the high±tension cords.
10. REMOVE RH HIGH±TENSION CORD CLAMPS (a) Re mo ve th e two bo lts an d two hi gh±tension cord
clamps.
(b) Remove the cord clamp from the front high±tension cord clamp.
11. REMOVE LH HIGH±TENSION CORD CLAMPS (a) Re mo ve th e two bo lts an d two hi gh±tension cord
clamps.
(b) Remove the cord clamp from the front high±tension cord clamp.
12. REMOVE LOWER HIGH±TENSION CORD COVER Remove the bolt and high±tension cord cover.
IG±14
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IGNITION SYSTEM High±Tension Cords and Cord Clamps
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4. INSTALL HIGH±TENSION CORDS(a) Connect the high±tension cords to the spark plugs anddistributor caps.
(b) Secure the high±tension cords with the cord clamps as
shown in the illustration.
(b) Connect the high±tension cords to the ignition coils.w Insert the grommet portion into the terminal hole of
the ignition coil.
IG±16
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IGNITION SYSTEM High±Tension Cords and Cord Clamps
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wAlign the spline of the ignition coil with the spline of
the holder, and slide on the holder.
NOTICE: Check that holder is correctly installed to the
grommet and ignition coil as shown in the illustration. w Check that the lock claw of the holder is engaged
by lightly pulling the holder.
5. INSTALL RH NO.3 TIMING BELT COVER (a) Install the three gaskets to the timing belt cover.
(b) Fit portion A of the timing belt cover, matching it with the
lower high±tension cord cover.
(c) Install the timing belt cover with the three bolts.
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IGNITION SYSTEM High±Tension Cords and Cord ClampsIG±17
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SERVICE SPECIFICATIONS
SERVICE DATA
IgnitionT/M in N range105 BTDC @ idle
timing[Check connector terminals TE1 and E1 con-
nect]
Spark plugTypeNDPK16R11
NGK BKR5EP11
GAPSTD 1.1 mm0.043 in.
Limit 1.3 mm0.051 in.
High±tensionResistanceLimit25 k W per cord
cord
Ignition coilPrimary coil resistance0.2±0.3

Secondary coil resistance6±11 k

DistributorAir gaps0.2±0.4 mm0.008±0.016 in.
Pickup coil resistance (cold)G1±G (±) 125±190 W
G2±G (±) 125±190 W
NE±G (±)155±240 W
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IGNITION SYSTEM Service SpecificationsIG±15
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