What Causes High Cylinder Pressure?

[DeAdam]

The main reason for excessively high cylinder pressure is excessive carbon buildup in the combustion chamber, which requires cleaning. During engine repair, excessive grinding of the mating surface between the cylinder block and cylinder head can reduce the combustion chamber volume, resulting in an excessively high compression ratio and consequently high cylinder pressure. This issue can be resolved by replacing the cylinder gasket or cylinder head. Below is the method for measuring cylinder pressure using a cylinder pressure gauge: 1. Run the engine until it reaches normal operating temperature; for water-cooled engines, the coolant temperature should be between 75-95°C. 2. Remove all spark plugs or fuel injectors (for diesel engines). 3. Fully open the throttle and choke valves. 4. Press the conical rubber adapter of the cylinder pressure gauge firmly into the spark plug hole of the cylinder being tested, or screw the threaded adapter into the spark plug hole. 5. Use the starter to rotate the crankshaft for 3-5 seconds. Read the measurement once the pointer stabilizes, then press the one-way valve to reset the pointer to zero. Each cylinder should be measured at least twice. 6. Repeat the above steps sequentially for each cylinder.