FIVE SIGNS OF MALFUNCTION

1. Engine jerks at idle.

Sometimes the vibrations are so strong that you can feel them in the steering wheel, gear lever, and car body. In addition, the idling rotational speed of the engine is unstable.

2. Reduced engine power.

You may particularly notice malfunctions in engine operation when you press the accelerator pedal, as well as jerks on acceleration. The ‘Check Engine’ indicator may light up on the dashboard.

3. Carbon deposits on the spark plugs and cracks in the high-voltage wires. These are usually easy to spot when inspecting parts.

4. Unusual sounds when the engine is running. For instance, intermittent sounds can be heard instead of a steady hum.

5. Increased fuel consumption. This is typically caused by problems with the fuel mixing and ignition processes.

THREE CAUSES OF ENGINE MISFIRE

- Problems in the ignition system. Faulty spark plugs, broken coils and high-voltage wires, or incorrect settings can cause the ignition to fire too early or too late, which in turn disrupts the combustion process of the fuel-air mixture and leads to engine malfunction.

- Disruption of the fuel supply and mixing processes. Soiling of the fuel injectors and malfunction of solenoid valves, clogging of the air filter, leaks in the intake or fuel supply systems or brake vacuum booster can cause a lean or rich air/fuel mixture, which affects combustion efficiency. Failure of the mass airflow sensor, throttle position sensor, or idle air control valve has similar consequences.

- Combustion chamber leakage. This is usually caused by the burning of the valves, pistons, cylinder head gasket, and scuffing on the cylinder surface. It can also be caused by incorrect valve adjustment, faulty tappets or hydraulic tappets, or incorrect valve timing.