Exhaust Systems Specialist Flashcards

During a converter efficiency test, the downstream O2 sensor stays steady near 0.6–0.7 volts. This indicates the converter is:

Answer: Storing oxygen and working efficiently

A steady mid-range downstream voltage shows the converter is storing and using oxygen properly.

A glowing red catalytic converter during operation is a sign of what serious condition?

Answer: Raw fuel burning inside the converter from a misfire or rich condition

Raw fuel reaching the converter, often from a misfire, ignites inside it and causes overheating and glowing.

What is the correct procedure when an oxygen sensor is seized in the exhaust pipe?

Answer: Apply penetrating oil and heat the surrounding metal, then remove

Penetrating oil and gentle heat expand the bung threads, allowing safe removal without damaging the bung.

Which condition would cause a properly functioning exhaust system to produce a hissing or ticking noise near the manifold?

Answer: A small exhaust leak at the manifold gasket

A small manifold gasket leak releases pressurized exhaust, creating a ticking or hissing sound near the engine.

When diagnosing a P0430 code, which bank's catalyst efficiency is being reported?

Answer: Bank 2

P0430 indicates catalyst efficiency below threshold on Bank 2, the bank not containing cylinder 1.

A dual exhaust system uses a crossover (H-pipe or X-pipe) primarily to:

Answer: Balance pressure pulses between banks and improve flow and sound

A crossover equalizes pressure pulses between the two banks, improving scavenging, flow, and tone.

After replacing a catalytic converter, why is it important to repair the underlying cause of failure first?

Answer: To prevent the new converter from being damaged by the same condition

If the root cause like a misfire or rich mixture remains, it will quickly destroy the new converter.