Practice question

A school bus diesel idles roughly and has a knock that disappears when one injector is electronically disabled. This indicates the problem is MOST likely:

  1. A general fuel quality issue affecting all cylinders
  2. A faulty SCR catalyst
  3. Related to that specific cylinder, such as its injector, valve, or piston
  4. A weak battery

Answer: C — Related to that specific cylinder, such as its injector, valve, or piston

The correct answer is shown above. Try the full quiz for additional practice.

Practice more: ASE S2 Diesel Engines (School Bus) Practice Questions - ASE S2 - Diesel Engines (School Bus) Certification Exam →