Compression Check: Testing and Inspection

COMPRESSION PRESSURE

Inspection

1.Warm up engine thoroughly. Then, stop it.
2.Release fuel pressure. Refer to the following table:






CAUTION:
If CONSULT is not used to release fuel pressure leave the fuel pump fuse disconnected until step
7.
3.Remove fuel pump fuse in IPDM E/R.
NOTE:
- For the fuse number, refer to the following table:





- For the fuse arrangement, refer to "Fuse, Connector and Terminal Arrangement" Fuse, Connector and Terminal Arrangement.
4.Remove engine cover. Refer to "Exploded View" Exploded View.
5.Remove ignition coil and spark plug from each cylinder. Refer to "Exploded View" Exploded View.
6.Connect engine tachometer (not required in use of CONSULT).





7.Install the compression tester with Tool [SST: EG15050500 (J45402)] into the spark plug hole.
8.Measure compression pressure using compression gauge connected with flexible type adapter (commercial service tool).
9.With accelerator pedal fully depressed, turn ignition switch to "START" for cranking. When the gauge pointer stabilizes, read the compression pressure and the engine rpm. Perform these steps to check each cylinder.
Compression pressure: Refer to "General Specification" General Specification.

CAUTION:
- Measure a six-cylinder under the same conditions since a measurement depends on measurement conditions (engine water temperature, etc.).
- Always use a fully changed battery to obtain the specified engine speed.
- 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. Refer to "How to Handle Battery" Procedures.
- If compression pressure is below the 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 checking, measure compression pressure again.
- If a cylinder has low compression pressure, pour a small amount of engine oil into the spark plug hole of the cylinder to re-check it for compression.
- If the added engine oil improves the compression, piston rings may be worn out or damaged. Check piston rings and replace if necessary. Refer to "Disassembly and Assembly" Disassembly and Assembly.
- If the compression pressure remains at low level despite the addition of engine oil, valves may be malfunctioning. Check valves for damage. Replace valve or valve seat accordingly. Refer to "Disassembly and Assembly" Disassembly and Assembly.
- If two adjacent cylinders have respectively low compression pressure and their compression remains low even after the addition of engine oil, cylinder head gaskets are leaking. In such a case, replace cylinder head gaskets. Refer to "Removal and Installation" Removal and Replacement.
10.After inspection is completed, install removed parts.
11.Start the engine, and check that the engine runs smoothly.
12.Perform trouble diagnosis. If DTC appears, erase it. Refer to the following table: