What is typically the effect of using a fuel grade that does not meet engine specifications?

Using a fuel grade that does not meet engine specifications can lead to a decrease in engine efficiency and potential engine damage. This is because different fuel grades have varying combustion characteristics, such as octane rating and energy content. If the fuel used has a lower octane rating than recommended for the engine, it can lead to premature ignition or knocking, which causes excessive heat and pressure within the combustion chamber.

This can decrease overall engine performance, leading to less power and increased fuel consumption, thereby decreasing efficiency. The repeated use of inappropriate fuel can also compromise engine components, cause excessive wear, or even lead to catastrophic engine failure. Thus, adhering to the manufacturer’s fuel specifications ensures optimal performance and longevity of the engine.