ASE G1 Auto Maintenance and Light RepairEngine SystemsMedium
A technician is diagnosing a vehicle that exhibits a strong sulfur-like odor from the exhaust, particularly after hard acceleration. Which of the following is the most likely cause?
- AA faulty catalytic converter
- BA clogged air filter
- CAn overfilled crankcase
- DA loose serpentine belt
Show answer & explanationAnswer & explanation
Correct answer: A. A faulty catalytic converter
A strong sulfur-like, or 'rotten egg,' odor from the exhaust is a classic symptom of a failing or overloaded catalytic converter. The converter is designed to convert hydrogen sulfide into odorless compounds, and when it fails, this odor becomes noticeable.
Why the other options are wrong
- B. A clogged air filter would primarily affect engine performance and fuel economy, not cause a sulfur smell.
- C. An overfilled crankcase can cause oil consumption and smoke, but not typically a sulfur odor from the exhaust.
- D. A loose serpentine belt would cause squealing noises and issues with driven accessories, unrelated to exhaust odor.
Catalytic Converter Failure
A common cause of a sulfur-like (rotten egg) smell from vehicle exhaust, indicating the converter is not properly processing exhaust gases.
- Converts harmful pollutants into less toxic ones.
- Sulfur smell often due to incomplete conversion of hydrogen sulfide.
- Can also cause reduced engine performance or a 'check engine' light.
Memory trick: Smelly exhaust, it's a 'cat'astrophe!