Catalytic converters reside at the end of your car’s exhaust system, taking harmful
gasses and turning them into less harmful emissions through chemical reactions.
Clogged filters lead to improper air and fuel mixtures in the combustion chamber,
resulting in poor acceleration and reduced gas mileage.
Signs of a Bad Catalytic Converter
Catalytic converters are an essential part of your car’s exhaust system, helping
maintain an appropriate air-to-fuel ratio in your combustion chamber and avoiding
issues like engine misfires, knocking, backfiring and excessive emissions.
As time progresses, your catalytic converter may require replacing. A malfunctioning
converter may lead to decreased gas mileage by restricting exhaust flow; forcing
engines to work harder for less power output.
A catalytic converter is composed of lightweight ceramic material with an interlaced
honeycomb structure. While designed to withstand high heat, excess debris such as
damaged oxygen sensors or unburned fuel from faulty spark plugs may cause
damage that fractures the converter and breaks into tiny fragments that rattle
around in your car.
Rattling Noises
Rattling noises during idle or driving are the telltale sign that your catalytic
converter has failed. These noises come from honeycomb material inside your
converter which has disintegrated due to heat or damage, with pieces entering your
exhaust system and eventually clogging up mufflers.
Your catalytic converter’s honeycomb is wrapped in ceramic material to protect it
from physical damage; however, this protection may not be enough to fend off
rocks, potholes, side curbs and speed bumps from hitting it and cracking it open,
leading to restricted oxygen flow into your engine and an increase in exhaust
backpressure resulting in decreased power output and increased exhaust back
pressure.
Loss of Power
An improper catalytic converter creates back pressure in the exhaust system that
restricts air flow to your engine, leading to reduced acceleration power and
decreasing gas mileage as your engine injects excess fuel due to reduced airflow.
You may also notice decreased gas mileage as its lack causes your engine to
overcompensate with extra fuel injection.
Identify when performance has decreased by using a vacuum gauge; make sure the
car has reached optimal operating temperature first before conducting this test
safely without touching hot exhaust pipes; for most accurate readings use a
manifold vacuum tester.
Check Engine Light
Signs that your catalytic converter may be failing can vary, with decreased gas
mileage being the most telling. Since it sits directly alongside the exhaust system,
clogs in it can restrict airflow and throw off your air-fuel ratio – often leaving behind
an unpleasant rotten egg smell or rattling noise in its wake.
To check if your catalytic converter is leaking, a vacuum gauge and thermometers
will come in handy. Once the car has reached optimal operating temperature, set it
in neutral or park and connect the vacuum gauge to its inlet pipe; after measuring
pressure for several minutes the reading should gradually decrease and stabilize
before returning back to its initial value.
Reduced Gas Mileage
If your gas tank seems to require frequent fill-ups, a possible culprit could be a
blocked catalytic converter. As part of your vehicle’s exhaust system, a blocked
converter disrupts airflow through its engine, forcing more fuel than necessary into
production resulting in poor gas mileage and worsening its effects over time. Fixing
this quickly will only exacerbate matters further.
Unother common indicator of a failing catalytic converter is an unpleasant rotten egg
scent. This is caused by gasoline containing sulfur which gets converted to
innocuous hydrogen sulfide in the catalytic converter; if its functionality fails,
however, this could leak into the cabin or atmosphere and even damage other
engine components, including spark plugs.