Murano FWD V6-3.5L (VQ35DE) (2006)
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Compression Check: Testing and Inspection
On-Vehicle Service
CHECKING COMPRESSION PRESSURE
1. Warm up engine thoroughly. Then, stop it.
2. Release fuel pressure.
3. Disconnect fuel pump fuse to avoid fuel injection during measurement.
4. Remove engine cover.
5. Remove ignition coil and spark plug from each cylinder.
6. Connect engine tachometer (not required in use of CONSULT-II).
7. Install compression tester with adapter onto spark plug hole.
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Use compression gauge whose picking up end inserted to spark plug hole is smaller than 20 mm (0.79 inch) in diameter. Otherwise, it may be
caught by cylinder head during removal.
8. With accelerator pedal fully depressed, turn ignition switch to "START" for cranking. When the gauge pointer stabilizes, read the compression
pressure and engine rpm. Perform these steps to check each cylinder.
Compression pressure
CAUTION: Always use a fully changed battery to obtain specified engine speed.
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If the engine speed is out of the specified range, check battery liquid for proper gravity. Check the engine speed again with normal battery
gravity.
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If compression pressure is below minimum value, check valve clearances and parts associated with combustion chamber (valve, valve seat,
piston, piston ring, cylinder bore, cylinder head, cylinder head gasket). After the checking, measure compression pressure again.
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If some cylinders have low compression pressure, pour small amount of engine oil into spark plug hole of cylinder to re-check it for
compression.
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If the added engine oil improves the compression, piston rings may be worn out or damaged. Check piston rings and replace if necessary.
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If the compression pressure remains at low level despite the addition of engine oil, valves may be malfunctioning. Check valves for