Toyota Sequoia (2005). Manual — part 648
EM–2
–
ENGINE MECHANICAL
CO/HC
2581
5.
IMMEDIATELY CHECK CO/HC CONCENTRATION AT
IDLE AND/OR 2,500 RPM
HINT:
When performing the 2 mode (2,500 rpm and idle) test, follow
the measurement orders are prescribed by the applicable local
regulations.
If the CO/HC concentration does not comply with regulations,
perform troubleshooting in the order given below.
(a)
Check the air–fuel ratio sensors and heated oxygen sen-
sors operation.(See page
(b)
See the table below for possible causes, and then inspect
and correct the applicable causes if necessary.
CO
HC
Problems
Causes
Normal
High
Rough idle
7. Faulty ignitions:
Incorrect timing
Fouled, shorted or improperly gapped plugs
8. Incorrect valve clearance
9. Leaky intake and exhaust valves
10.Leaky cylinders
Low
High
Rough idle
(fluctuating HC reading)
1. Vacuum leaks:
PCV hoses
Intake manifold
Throttle body
Brake booster line
2. Lean mixture causing misfire
High
High
Rough idle
(Black smoke from exhaust)
1. Restricted air filter
2. Faulty SFI systems:
Faulty pressure regulator
Defective ECT sensor
Faulty ECM
Faulty injectors
Faulty throttle position sensor
Faulty MAF meter
EM0KR–10
A04458
Compression
Gauge
–
ENGINE MECHANICAL
COMPRESSION
EM–3
2582
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 SPARK PLUGS
(See page
)
3.
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:
1,373 kPa (14.0 kgf/cm
2
, 199 psi) or more
Minimum pressure:
1,030 kPa (10.5 kgf/cm
2
, 149 psi)
Difference between each cylinder:
98 kPa (1.0 kgf/cm
2
, 14 psi) or less
(e)
If the cylinder compression in one or more cylinders is low,
pour small amount of engine oil into the cylinder through
the spark plug hole and repeat steps (a) through (c) for
cylinders with low compression.
If adding oil helps the compression, chances are
that the piston rings and/or cylinder bore are worn
or damaged.
If pressure stays low, a valve may be sticking or
seating is improper, or there may be leakage past
the gasket.
4.
REINSTALL SPARK PLUGS
(See page
)
EM0KS–09
A23300
A23301
EM–4
–
ENGINE MECHANICAL
VALVE CLEARANCE
2583
VALVE CLEARANCE
INSPECTION
HINT:
Inspect and adjust the valve clearance when the engine is cold.
1.
REMOVE BATTERY CLAMP COVER
2.
REMOVE THROTTLE BODY COVER
3.
REMOVE AIR CLEANER AND INTAKE AIR CONNEC-
TOR ASSEMBLY
4.
REMOVE NO.3 TIMING BELT COVERS
(See page
5.
REMOVE IGNITION COILS (See page
)
6.
REMOVE RH CYLINDER HEAD COVER
Remove the 9 bolts,
seal washers and cylinder head cover.
7.
REMOVE LH CYLINDER HEAD COVER
(a)
Remove the oil dipstick for the transmission.
(b)
Disconnect the PCV hose.
(c)
Disconnect the engine wire clamp from the wire bracket
on the cylinder head cover.
(d)
Remove the 9 bolts, 9 seal washers and cylinder head
cover.
8.
SET NO.1 CYLINDER TO TDC/COMPRESSION
(a)
Turn the crankshaft pulley, and align its groove with timing
mark ”0” of the No.1 timing belt cover.
(b)
Check that the timing marks of the camshaft timing pul-
leys and timing belt rear plates are aligned.
If not, turn the crankshaft 1 revolution (360
°
) and align the mark
as above.
A05717
RH Cylinder Head
LH Cylinder Head
Front
A04457
RH Cylinder Head
LH Cylinder Head
Front
–
ENGINE MECHANICAL
VALVE CLEARANCE
EM–5
2584
9.
INSPECT VALVE CLEARANCE
(a)
Check only the valves indicated.
Using a feeler gauge, measure the clearance be-
tween the valve lifter and camshaft.
Record the out–of–specification valve clearance
measurements. They will be used later to determine
the required replacement adjusting shim.
Valve clearance (Cold):
Intake
0.15 – 0.25 mm (0.006 – 0.010 in.)
Exhaust
0.25 – 0.35 mm (0.010 – 0.014 in.)
(b)
Turn the crankshaft 1 revolution (360
°
) and align the mark
as above. (See procedure in step 8)
(c)
Check only the valves indicated as shown. Measure the
valve clearance. (See procedure in step (a))
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