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Maple Valley Auto Repair

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Mon - Fri: 8:00 AM - 5:00 PM
Give Us a Call:(425) 310-1100
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What are the Symptoms of a Bad Catalytic Converter?

Signs of a malfunctioning catalytic converter are not as apparent as an overheating engine or faulty braking system. It is important to note that your vehicle's catalytic converter will malfunction, mainly when you ignore problems with connected parts such as exhaust valves and spark plugs.

What is a Catalytic Converter?

It is a metal canister that reduces emissions from your auto to prevent environmental pollution. It sits between the muffler and car engine to eliminate or reduce your car exhaust system emissions. Thanks to the chemical catalyst, the latter remains possible, usually comprising palladium and platinum that convert emissions into environmentally friendly gasses.

Common Symptoms of a Bad Catalytic Converter

Mainly, you will know that your catalytic converter has gone bad once you fail your upcoming emission test. See if you can spot the following symptoms of a bad catalytic converter to know when it is time for a replacement:

1. Reduced Engine Performance

A clogged catalytic converter can impact engine performance. It can easily restrict exhaust flow, resulting in reduced acceleration and engine power. A faulty catalytic converter may be a culprit if you notice reduced engine power going uphill or during acceleration.

2. Rattling Noise

A malfunctioning catalytic converter that remains damaged internally can cause rattling noises from under the vehicle. A rich fuel mixture can break the honeycomb meshes of the converter, causing a rattle.

3. Watch Out for a Sulfur Smell from the Exhaust

A properly working catalytic converter emits hydrogen sulfide by converting it to odorless sulfur dioxide. Hydrogen sulfide is commonly identified by its rotten egg-like smell. Therefore, an exhaust with a bad catalytic converter will produce this odor from unburned fuel.

4. Check Engine Light Comes On

Modern cars come with an air-fuel ratio sensor or oxygen sensor that monitors the gas level in the exhaust. The Check Engine Light blinks to warn you of a problem if the catalytic converter is not working correctly.

The Bottom line

Now that you know the most common symptoms of a bad catalytic converter, you can tell when you install a new one. If you notice these signs and need catalytic converter repair, visit or give Rainier Automotive a call today!

23933 SE 264th St. Ste. A Maple Valley, WA 98038 (425) 310-1100
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