Spark plugs serve as a reliable indicator of the condition of a gasoline engine. They can accurately identify malfunctions and problems in the operation of the unit with a high degree of probability.
The performance of spark plugs in gasoline engines can be greatly influenced by the air filter. When the filter becomes clogged with dirt, the engine can experience reduced airflow, leading to incomplete combustion of the fuel. This incomplete combustion results in the formation of black deposits on the spark plugs. In such cases, the use of a cheap filter can cause damage to the engine parts, leading the car owner to believe that there are serious problems with the power unit.
The condition of the injectors should be the second thing to consider. When one or more of them begin to leak, an oily coating appears on them. If the engine has direct injection and the fuel system pressure increases, the spark plug electrodes will quickly turn black.
To diagnose the problem, it’s important to check the fuel pressure in the rail. This will help determine the condition of the regulator, which can cause a rich air-fuel mixture and lead to soot buildup on the spark plugs.
It’s important not to overlook the various sensors in the engine, as they send signals to the car’s ECU, which acts as its “brain”. It is then the responsibility of the electronics to start the mixing process.
One of the most important sensors is the mass air flow sensor (MAF). It serves as a “meter” for the amount of air entering the cylinders.
The mass air flow sensor (DMRV) is critical for accurate measurement of the amount of air entering the engine’s cylinders. However, in some used cars, the sensor may begin to fail prematurely or even detach entirely. This can result in the electronic control unit sending inaccurate commands to the entire system, leading to a range of issues including blackened spark plugs, engine malfunctions, increased fuel consumption, and other unexpected problems.
Another seemingly minor detail that can cause problems is poor ground contact. This can result in low voltage being applied to the ignition coil, leading to a weak spark from the spark plug. If the engine is also suffering from oil burn, these two factors can cause a greasy black coating on the electrode.