ABYC Diesel Practice Exam

What component, if malfunctioning, might lead to increased fuel consumption in a mechanically fuel-injected engine?

1. Fuel injectors

2. Oil filter

3. Transom assembly

4. Throttle cable

The correct answer is: Fuel injectors

In a mechanically fuel-injected engine, the fuel injectors are crucial components responsible for delivering the precise amount of fuel into the combustion chamber for effective combustion. If the fuel injectors malfunction, they may either deliver too much fuel or not atomize the fuel correctly, leading to inefficient combustion. This results in increased fuel consumption as the engine compensates for the inefficiency, causing a rise in overall fuel usage. For instance, if the injectors are clogged or leaking, they may cause a richer fuel-air mixture, which is not optimal for fuel efficiency. Proper functioning of the fuel injectors ensures that the engine operates at its designed performance parameters, thus maintaining fuel economy. Other components listed, like the oil filter, transom assembly, and throttle cable, do not have a direct impact on the fuel delivery system in the same way that fuel injectors do, making them less likely to be the root cause of increased fuel consumption in this context.