What Causes Insufficient Cylinder Pressure?
2 Answers
Insufficient cylinder pressure can be caused by: 1. Severe wear of piston rings leading to reduced sealing effectiveness; 2. Abnormal wear such as uneven cylinder wall scoring; 3. Poor sealing of valve seats or spark plug seats; 4. Damaged cylinder gasket. Cylinder pressure refers to the internal pressure during piston compression, which can be measured using a cylinder pressure gauge. If there is no cylinder pressure, engine disassembly for repair is necessary. Engine cylinder pressure is related to factors such as oil viscosity, the fit condition of the cylinder-piston assembly, the correct adjustment of the valve train, and the sealing of the cylinder gasket. Therefore, measuring engine cylinder pressure can help diagnose the sealing condition of cylinders and piston assemblies, the effectiveness of piston rings, valves, and cylinder gasket sealing, as well as whether the valve clearance is appropriate.
I remember previously discovering insufficient cylinder pressure, mainly caused by worn piston rings leading to decreased compression, making the car feel particularly sluggish with slow acceleration and high fuel consumption. During that inspection, it was also found that there were issues with poor valve sealing, with aging valve seat rings causing air leaks. Additionally, scratches on the cylinder walls or oil leaks from the cylinder head gasket can also affect pressure, especially noticeable as shaking during cold starts. Preventive measures include regularly changing to high-quality engine oil to avoid impurity buildup and checking the engine condition every 5,000 kilometers. Don't wait until the noise becomes loud before repairing, otherwise, a major overhaul costing thousands wouldn't be cost-effective. If you encounter similar issues during daily driving, first visit a small shop to test with a pressure gauge, which should suffice.
