Keeping American Motors AMX Models Roaring with Optimal Catalytic Converters

American Motors AMX Catalytic Converters: The American Motors Corporation AMX was a unique muscle car from 1968 to 1970. Only available as a two-seater, this powerful performance coupe came equipped from the factory with options like a 290 or 343 cubic-inch V8 paired with manual or automatic gearboxes. While catalytic converters were not mandated during that era, modern AMX owners looking to comply with emissions regulations can find aftermarket catalytic converter solutions designed to fit their vehicles. These converters are crucial in reducing harmful emissions, promoting cleaner air, and ensuring environmental compliance without compromising AMX’s powerful and iconic performance.

As a classic muscle machine, the AMX utilized simple emissions equipment compared to modern vehicles. However, keeping the exhaust system running cleanly is still vital for reliability and preventing damage over tens of thousands of hard-accelerating miles. This extensive guide dives into everything AMX owners should know about maintaining, repairing, and replacing catalytic converters in their prized vehicles.

Direct-fit replacement American Motors AMX Catalytic Converters are available from aftermarket brands like Bosal, Eastern Catalytic, and Walker. Proper inlet/outlet dimensions and flange style must match the original converters. American Motors AMX Catalytic Converters sold in California must be CARB-compliant.

Function of Catalytic Converters in AMC AMX Vehicles

Catalytic converters are emissions control devices that convert toxic engine exhaust like hydrocarbons, carbon monoxide, and nitrogen oxides into less harmful compounds. This helps the AMX pass emissions inspections and reduces pollution.

Converters consist of a stainless steel housing containing a substrate coated with precious metal catalysts to facilitate chemical reactions. Over time, contaminants can build up and restrict flow through the converter, necessitating replacement.

Aftermarket universal fit converters are available, offering CARB-compliance and a range of high-flow designs to prevent hindering AMX performance.

Own an AMC Eagel & want to Improve its converter? Read our guide on How To Extend the Life of American Motors Eagle Catalytic Converters.

Evaluating Faulty AMC AMX Catalytic Converters

If the AMX’s original catalytic converter remains, it may need replacement after 50+ years of use. Some symptoms of a clogged or damaged converter include:

  • Lackluster acceleration
  • Reduced fuel economy
  • Fouled spark plugs
  • Visible damage or corrosion on the external converter housing

Trouble codes may also illuminate the Check Engine light if the oxygen sensor detects inefficient catalytic conversion or flow. This necessitates the diagnosis of the converter.

Carefully inspecting the internal ceramic honeycomb structure will also reveal any melting, collapse of the substrate, or significant contaminant buildup impeding exhaust flow through the element.

AMX Catalytic Converter Installation Considerations

When replacing an AMX’s worn-out catalytic converter, owners should consider the following:


Opting for a CARB-approved aftermarket converter ensures emissions compliance. CARB regulates catalytic converters in California to meet clean air targets.

Proper Positioning

The AMX converter must bolt directly to exhaust manifold outlets to enable immediate heating for light-off and proper functionality.

Professional Installation

Given the AMX’s age, having a shop replace any exhaust components ensures proper alignment and sealing. Attempting to DIY risks further damage or leaks. Most shops also handle disposing of old converters properly.

Benefits of a High-Flow AMX Catalytic Converter

Beyond just emissions compliance, upgrading to a top-notch high-flow catalytic converter also provides AMX owners with added performance benefits:

Improved Acceleration

Reduced backpressure from the optimized internals of a high-flow converter can help increase trap speeds and shave seconds off quarter-mile times. This allows the venerable AMX V8 to roar at full song indeed.

Enhanced Engine Longevity

Keeping exhaust bottlenecks to a minimum reduces strain on the AMX powerplant. Uncorking the exhaust also enables precise fuel metering for cleaner combustion, preventing engine wear over extended high-RPM use.

Investing in a suitable catalytic converter maximizes AMC muscle at its best for many more miles of enjoyment.

Warning Signs of Failing AMX Catalytic Converters

Catching catalytic converter problems early is key to avoiding collateral damage. Warning signs of issues include:

Check Engine Light

If the oxygen sensor detects inefficient converter performance, it may trigger error codes illuminating the Check Engine light. Technicians should promptly diagnose the converter when this happens.

Noisy Operation

Rattling noises during acceleration can indicate the AMX’s internal converter substrate has begun to deteriorate. This necessitates immediate replacement to prevent chunks from exiting the tailpipe.

Poor Drivability

Sluggish acceleration accompanied by black smoke from the tailpipe points to a severely clogged or damaged converter needing replacement. Allowing problems to persist risks engine damage.

Address any catalytic converter deficiencies promptly before minor issues lead to larger headaches down the road!

Maximizing AMC AMX Catalytic Converter Lifespan

With attentive care and maintenance, a quality aftermarket AMX catalytic converter should deliver years of reliable emissions control and high RPM excitement.

Use Fuel Additives

Periodically adding detergent-based fuel system treatments helps remove carbon deposits in combustion chambers and the converter that can restrict flow.

Drive Responsibly

Allowing proper engine warm-up before stomping the accelerator avoids raw fuel damage to the converter. Easy highway driving also enables gases to fully combust and exit the tailpipe.

Keeping after the small things ensures big AMX grins for years to come.

FAQs related to AMX Catalytic Converter

Why is the catalytic converter important in an American Motors AMX?

The catalytic converter in an American Motors AMX is crucial for reducing harmful emissions by converting pollutants in the exhaust gases into less harmful substances. It helps the vehicle comply with emissions standards.

How can I identify a failing catalytic converter in my American Motors AMX?

Signs of a failing catalytic converter in your American Motors AMX may include diminished engine performance, increased exhaust emissions, strange odors, and the illumination of the Check Engine Light. If you notice these symptoms, it’s advisable to have your vehicle inspected.

Can I replace the catalytic converter in my American Motors AMX with an aftermarket one?

Yes, you can replace the catalytic converter in your American Motors AMX with an aftermarket option. Ensure that the chosen converter meets or exceeds OEM specifications and complies with emissions regulations in your area.

Are different catalytic converters available for the American Motors AMX?

Yes, direct-fit catalytic converters are designed specifically for the American Motors AMX. You may also find universal converters that require modification for installation. Choose the type that best fits your needs and vehicle specifications.

What is the typical lifespan of a catalytic converter in an American Motors AMX?

The lifespan of a catalytic converter in an American Motors AMX can vary based on driving conditions and maintenance. On average, they can last around 100,000 miles or more. Regular maintenance and promptly addressing engine issues can help extend the converter’s life.

Can I upgrade to a high-performance catalytic converter for my American Motors AMX?

You can upgrade to a high-performance catalytic converter for improved exhaust flow and potential performance enhancements. Ensure that the chosen converter complies with emissions regulations in your area.

How do I know if a catalytic converter is compatible with my American Motors AMX model year?

When purchasing a catalytic converter for your American Motors AMX, ensure it is designed for your specific model year. Look for direct-fit options that match your vehicle’s specifications for proper installation and performance.

Are there specific maintenance considerations for American Motors AMX catalytic converters?

Routine maintenance of your American Motors AMX, which includes addressing engine issues, contributes to the longevity of the catalytic converter. Follow the manufacturer’s recommendations for maintenance intervals.

Can a damaged catalytic converter affect my American Motors AMX fuel efficiency?

A damaged catalytic converter can negatively impact fuel efficiency in your American Motors AMX. If the converter is not functioning properly, it can lead to decreased engine performance and reduced fuel economy.

Can I clean a clogged catalytic converter in my American Motors AMX?

Cleaning a clogged catalytic converter is not a common or recommended practice. Once a catalytic converter is clogged or damaged, replacement is often necessary for optimal vehicle performance and emissions control.


As emissions devices on muscle car legends like the AMC AMX, catalytic converters play crucial roles in clean air compliance, enabling these classics to roar tirelessly for years. With this guide’s tips on evaluating, selecting, and maintaining AMX catalytic converters properly, enthusiasts have all the tools to keep their rare rides running optimally.

I am Nicolas, an automobile engineer with over 5 years of experience in exhaust systems and catalytic converters. I am passionate about learning and understanding how things work, and I am always looking for new ways to improve the performance and efficiency of automotive exhaust systems. Know more about me.