Catalytic fines comprised of aluminum oxide and/or silicon dioxide are a common contaminant of residual fuels. Which diesel engine components would be most effected by catalytic fines in fuel?

Correct Answer: Option C — High pressure fuel pumps and fuel injectors.

Catalytic fines are extremely hard, abrasive aluminum and silicon particles carried over from catalytic cracking in refineries. Due to extremely tight manufacturing tolerances and high-pressure differentials, high-pressure fuel pumps and injector nozzles suffer rapid, severe abrasive wear.