A diesel engine experiences a sudden loss in speed, accompanied by black exhaust smoke, with the fuel rack at maximum, and the speed remaining below normal. The probable cause is __________.
• Air-fuel ratio in diesel engines and how it affects exhaust color • What black smoke usually indicates in terms of combustion • How engine load vs. fuel rack position vs. RPM are related in a diesel
• Think about what happens if the engine is getting plenty of fuel (fuel rack at maximum) but still cannot reach normal speed—what might be limiting power output? • Which of the listed problems would most directly cause incomplete combustion and a rich mixture, leading to black smoke? • Consider whether each option would more likely cause a slow loss of compression, mechanical friction, or an air supply / load-related problem.
• Match the symptom black exhaust smoke with the typical cause (too much fuel vs. too little air). • Check which option most directly affects the amount of air available for combustion at a given fuel setting. • Verify which condition would cause the engine to lug (labor) at low RPM with maximum fuel rather than simply misfire or lose compression.
No comments yet
Be the first to share your thoughts!