EM–2
–ENGINE MECHANICALCO/HC
922Authorr:Datee:
2001 LEXUS ES300 (RM831U)
If the CO/HC concentration does not comply with regulations,
troubleshoot in the order given below.
See the table below for possible causes, and then inspect and
correct the applicable causes if necessary.
COHCProblemsCauses
NormalHighRough idle1. Faulty ignitions:
jIncorrect timing
jFouled, shorted or improperly gapped plugs
2. Incorrect valve clearance
3. Leaky intake and exhaust valves
4. Leaky cylinders
LowHighRough idle
(Fluctuating HC reading)
1. Vacuum leaks:
jPCV hoses
jIntake manifold
jAir intake chamber
jThrottle body
jIAC valve
jBreak booster line
2. Lean mixture causing misfire
HighHighRough idle
(Black smoke from exhaust)
1. Restricted air filter
2. Plugged PCV valve
3. Faulty SFI systems:
jFaulty pressure regulator
jDefective ECT sensor
jFaulty ECM
jFaulty injectors
jFaulty throttle position sensor
jFaulty MAF meter
EM03U–02
P19471Compression Gauge
–ENGINE MECHANICALCOMPRESSION
EM–3
923Authorr:Datee:
2001 LEXUS ES300 (RM831U)
COMPRESSION
INSPECTION
HINT:
If there is lack of power, excessive oil consumption or poor fuel
economy, measure the compression pressure.
1.WARM UP AND STOP ENGINE
Allow the engine to warm up to normal operating temperature.
2.REMOVE IGNITION COILS (See page IG–5)
3.REMOVE SPARK PLUGS
Using a 16 mm plug wrench, remove the 6 spark plugs.
4.CHECK CYLINDER COMPRESSION PRESSURE
(a)Insert a compression gauge into the spark plug hole.
(b)Fully open the throttle.
(c)While cranking the engine, measure the compression
pressure.
HINT:
Always use a fully charged battery to obtain engine speed of
250 rpm or more.
(d)Repeat steps (a) through (c) for each cylinder.
NOTICE:
This measurement must be done in as short a time as pos-
sible.
Compression pressure:
1,500 kPa (15.3 kgf/cm2, 218 psi)
Minimum pressure: 1,000 kPa (10.2 kgf/cm2, 145 psi)
Difference between each cylinder:
100 kPa (1.0 kgf/cm2, 15 psi) or less
(e)If the cylinder compression in 1 or more cylinders is low,
pour a small amount of engine oil into the cylinder through
the spark plug hole and repeat steps (a) through (c) for
cylinders with low compression.
jIf adding oil helps the compression, it is likely that
the piston rings and/or cylinder bore are worn or
damaged.
jIf pressure stays low, a valve may be sticking or
seating is improper, or there may be leakage past
the gasket.
5.REINSTALL SPARK PLUGS
6.INSTALL IGNITION COILS (See page IG–5)
EM03V–02
A07284
A05273
RH EX
RH IN
LH IN
LH EX
33
11Front
22
66
EM–4
–ENGINE MECHANICALVALVE CLEARANCE
924Authorr:Datee:
2001 LEXUS ES300 (RM831U)
VALVE CLEARANCE
INSPECTION
HINT:
Inspect and adjust the valve clearance when the engine is cold.
1.REMOVE RH FENDER APRON SEAL
2.DRAIN ENGINE COOLANT
3.REMOVE V–BANK COVER
(a)Using a 5 mm hexagon wrench, remove the 3 cap nuts.
(b)Loosen the V–bank cover fastener counterclockwise.
(c)Remove the V–bank cover.
4.REMOVE AIR INTAKE CHAMBER ASSEMBLY (See
page EM–31)
5.REMOVE IGNITION COILS
6.DISCONNECT UPPER RADIATOR HOSE FROM WA-
TER OUTLET
7.REMOVE CYLINDER HEAD COVERS
(See page EM–31)
8.SET NO.1 CYLINDER TO TDC/COMPRESSION
(a)Turn the crankshaft pulley, and align its groove with the
timing mark ”0” of the No.1 timing belt cover.
(b)Check that the valve lifters on the No.1 (IN and EX) are
loose.
If not, turn the crankshaft 1 revolution (360°) and align the mark
as above.
9.INSPECT VALVE CLEARANCE
(a)Check only those valves indicated in the illustration.
(1)Using a feeler gauge, measure the clearance be-
tween the valve lifter and camshaft.
(2)Record out of specification valve clearance mea-
surements. They will be used later to determine the
required replacement adjusting shim.
Valve clearance (Cold):
Intake0.15 – 0.25 mm (0.006 – 0.010 in.)
Exhaust0.25 – 0.35 mm (0.010 – 0.014 in.)
A05272
RH EX
RH IN
LH IN
LH EX
33
22Front
55
44
A05274
RH EX
RH IN
LH IN
LH EX
Front55
44
66P12919
Upward
Notch
–ENGINE MECHANICALVALVE CLEARANCE
EM–5
925Authorr:Datee:
2001 LEXUS ES300 (RM831U)
(b)Turn the crankshaft 2/3 of a revolution (240°), and check
only the valves indicated in the illustration. Measure the
valve clearance (See step (a)).
(c)Turn the crankshaft a further 2/3 of a revolution (240°),
and check only the valves indicated in the illustration.
Measure the valve clearance (See step (a)).
10.ADJUST VALVE CLEARANCE
(a)Remove the adjusting shim.
(1)Turn the camshaft so that the cam lobe for the valve
to be adjusted faces up.
(2)Turn the valve lifter with a screwdriver so that the
notches are perpendicular to the camshaft.。。。