What are the symptoms of insufficient cylinder pressure?
2 Answers
Symptoms of insufficient cylinder pressure: 1. Excessive carbon deposits, causing severe engine vibration; 2. Affects combustion efficiency, leading to reduced power, high fuel consumption, and even overheating; 3. If caused by piston seal failure, it will result in severe carbon buildup in the combustion chamber, poor emissions, and significantly shortened engine lifespan; 4. Heavy smoke from the exhaust pipe, engine malfunction or even stalling; 5. Downward leakage of combustible mixture increases crankcase pressure, potentially causing crankcase explosion in severe cases, while upward oil leakage into the cylinder leads to oil burning. For four-stroke engines, main causes of insufficient cylinder pressure include valve leakage, excessive clearance between piston/piston rings and cylinder block, and cylinder gasket leakage.
Insufficient cylinder compression is a common issue I encounter during car repairs, primarily stemming from engine combustion efficiency. The most noticeable symptom is difficulty starting, especially in cold weather, where you need to turn the key multiple times to get the engine to fire up—it feels like the engine is struggling to muster its strength. At idle, the engine shakes noticeably, vibrating the steering wheel and seats due to unstable combustion caused by inadequate compression. Power output drops significantly; acceleration feels sluggish, and even with the pedal floored, the car struggles to climb hills or overtake. Fuel consumption also rises noticeably because lower combustion efficiency means the same tank of gas covers fewer miles. Sometimes, you might hear unusual noises, like faint knocking or hissing sounds, indicating cylinder sealing issues. If left unaddressed, internal engine wear worsens—such as piston ring deformation or valve leaks—making repairs more costly. Regular cylinder compression checks or professional diagnostics can prevent minor issues from escalating, extending engine life.
