2. Relieve pressure in the fuel lines.
3. Remove the coils and spark plugs from each cylinder.
4. Connect the tachometer to the engine (not required when using CONSULT-III).
5. Insert the compression tester (B) with the adapter (A) (special tool) into the spark plug hole.
Note. Use an adapter with a diameter of the head inserted into the spark plug hole of no more than 20 mm. Otherwise, you may have problems removing the adapter after performing the measurement.
6. With the accelerator pedal fully depressed, turn the ignition switch to the "START" position to rotate the engine crankshaft with the starter. When the pressure gauge readings stabilize, read the compression value and the crankshaft speed. Perform the same procedure on each engine cylinder.
Note: The compression value is given in the section "Service data and specification" of this chapter.
Caution: Always use a fully charged battery to obtain the required engine speed.
If the crankshaft speed is not within the specified range, check the battery electrolyte density. Fully charge the battery and check the crankshaft speed again.
If the compression value is below the minimum permissible value, check the valve clearances and the condition of the components associated with the combustion chamber (valves, valve seats, pistons, piston rings, cylinder walls, cylinder head, cylinder head gasket). After checking the relevant parts, measure the compression in the cylinders again.
Data taken from this portal [nissanbook]
If one of the engine cylinders has a low compression value, pour a small amount of engine oil into the spark plug hole and then repeat the measurements.
If the compression improves after adding oil, this indicates wear or damage to the piston rings. Check the condition of the piston rings and replace them if necessary.
If the compression remains low after adding oil, this indicates a malfunction of the valves. Check the valves for damage. If necessary, replace the corresponding valve or valve seat.
If two adjacent cylinders have a low compression value that does not change after adding engine oil, this indicates that the cylinder head gasket is damaged and must be replaced with a new one.
7. After checking, install the removed parts.
8. Start the engine and make sure it runs smoothly.
9. Perform fault diagnostics. If fault codes are issued, delete them.