Practice question

A school bus diesel has a rough idle, and an injector return-flow (back-leakage) test shows one injector returning far more fuel than the others. This indicates:

  1. That injector is worn/leaking internally and is likely the cause of the miss
  2. That injector is in perfect condition
  3. All injectors must be replaced regardless
  4. A cooling system fault

Answer: A — That injector is worn/leaking internally and is likely the cause of the miss

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 →