What are the causes of insufficient cylinder pressure in the Familia II?
2 Answers
The causes of insufficient cylinder pressure in the Familia II are as follows: 1. Excessive wear of the cylinder or piston rings, as well as misalignment, sticking, or breakage of piston rings, leading to insufficient cylinder pressure. Prolonged exposure to high temperatures can cause insufficient elasticity in the piston rings, preventing proper sealing of the piston, which also results in insufficient cylinder pressure. 2. Damage or poor sealing of the cylinder gasket, leading to insufficient cylinder pressure. The cylinder gasket serves to isolate two cylinders independently, and damage to the gasket between adjacent cylinders can cause gas leakage between them, ultimately resulting in low pressure in both adjacent cylinders. 3. Warping of the cylinder head's lower surface, leading to insufficient cylinder pressure. High engine coolant temperature can cause the cylinder head to deform, losing its flatness and resulting in poor cylinder sealing, which manifests as insufficient pressure during cylinder pressure measurement. 4. Poor sealing of the intake and exhaust valves, leading to insufficient cylinder pressure. Erosion of the valve cone surface, bending or breakage of the valve, or improper adjustment of the valve clearance can all cause poor cylinder sealing and insufficient cylinder pressure.
I've encountered insufficient cylinder pressure quite a few times. The most common causes are worn piston rings or poor sealing, which leads to decreased compression. For the Famila II as an older model, it's quite normal for the piston rings to wear out after prolonged engine use – this could be due to subpar oil quality or inadequate maintenance. Another factor is poor valve sealing; if the valves are burnt or deformed, air leakage will significantly reduce cylinder pressure. There's also the issue of cylinder head gasket leaks – a cracked gasket allows combustion chamber pressure to escape. Once when I was repairing a car, I even found that loose spark plug installation or a clogged air filter could indirectly affect cylinder pressure. To diagnose it properly, you need to perform a cylinder compression test. First, use a pressure gauge to measure each cylinder's data, then compare it with standard values to pinpoint the fault. If the cylinder pressure is severely insufficient, you might need to replace the piston rings or re-hone the cylinder walls. It's time-consuming but worthwhile – otherwise, the engine will lack power and consume more fuel.
