2003 LEXUS LS430 spark plugs

f. Remove the spark plugs.
g. Disconnect the 8 injector connectors.
h. Check the cylinder compression pressure.
SST 09992-00500
1. Insert a compression gauge into the spark plug hole.
2. Fully open the throttle.
3. While cranking the engine, measure the compression pressure.
Compression pressure:
1.2 MPa (12.5 kgf/cm
2 , 178 psi)
Minimum pressure: 981 kPa (10.0 kgf/cm
2 , 142 psi)
Difference between each cylinder:
98 kPa (1.0 kgf/cm
2 , 14 psi)
4. If the cylinder compression is low, pour a small amount of engine oil into the cylinder
throu
gh the spark plug hole and inspect again.

Fig. 5: Checking Cylinder'S Compression Pressure
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
If adding oil increases the compression, the piston rings and/or cylinder bore may be worn or
damaged.
If pressure stays low, a valve may be stuck or seated improperly, or there may be leakage in
the gasket.
i. Connect the 8 injector connectors.
j. Install the spark plugs.
k. Install the 8 ignition coils.
l. Install the oil level gauge guide.
m. Connect the throttle control motor connector.
n. Install the air cleaner inlet and intake air pipe.
o. Install the V-bank cover.
10.INSPECT CO/HC
a. Start the engine.
b. Rev the engine at 2,500 rpm for approximately 180 seconds.

6. Visually check if spark occurs while the engine is being cranked.
If a spark does not occur, perform the test as follows:
Fig. 4: Spark Test Flow Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
7. Using a 16 mm (0.63 in.) plug wrench, install the spark plugs.
Torque: 18 N.m (180 kgf.cm, 13 ft.lbf)
8. Install the ignition coils (see REPLACEMENT
).

If the electrode his traces of wet carbon, clean the electrode with a spark plug cleaner and then dry
it.
Fig. 8: Cleaning Spark Plugs

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Air pressure: 588 kPa (6 kgf/cm
2 , 85 psi)
Duration: 20 seconds or less