A heavy-duty diesel engine is operating at full load. The technician observes exceptionally high exhaust gas temperatures and a noticeable decrease in power output. What is the most likely cause related to the 4-stroke cycle?

Question: A heavy-duty diesel engine is operating at full load. The technician observes exceptionally high exhaust gas temperatures and a noticeable decrease in power output. What is the most likely cause related to the 4-stroke cycle?

Answer options: ✅ Delayed fuel injection timing, causing combustion to occur late in the power stroke.

• A plugged air filter, restricting air intake and leading to an overly rich fuel-air mixture.
• Premature fuel injection timing, initiating combustion too early in the compression stroke.
• Excessive engine oil consumption, leading to deposits on the exhaust valves and reduced flow.

Correct answer: Delayed fuel injection timing, causing combustion to occur late in the power stroke.

Explanation: Delayed fuel injection timing results in combustion occurring later in the power stroke, reducing the effective work extracted and increasing exhaust gas temperatures as more heat is rejected through the exhaust manifold rather than converted to mechanical energy. This directly impacts engine efficiency and power output.