ABYC Diesel Practice Exam

If a high-pressure fuel line is replaced with a longer line, what effect does this have?

1. The pressure will increase

2. The timing will change

3. The engine will run cooler

4. The fuel will be delivered faster

The correct answer is: The timing will change

Replacing a high-pressure fuel line with a longer line affects the timing because the additional length can introduce a delay in the delivery of fuel to the injectors. When a fuel line is extended, the fuel has to travel a longer distance, which can lead to longer delays between the point where the fuel is pressurized and the point where it enters the combustion chamber. This delay can alter the timing of fuel injection, potentially impacting the engine's performance and efficiency. The other options do not accurately reflect the consequences of changing the length of the fuel line. Increasing the pressure, running cooler, or delivering fuel faster would not typically occur just by substituting a longer line, as the length and its inherent resistance would more likely complicate those functions.