Buy Mitsubishi Eclipse Catalytic Converters

The catalytic converter (often called a "cat," "cat converter," or "exhaust catalyst") on a Mitsubishi Eclipse is a metal can in the exhaust that turns harmful gases into cleaner air. It uses precious metals like platinum, palladium, and rhodium to scrub pollution. If it clogs, cracks, or gets stolen, the car can run rough, fail smog tests, and trigger a check‑engine light. New replacement units cost over $1,700 on average, and U.S. law makes it illegal to tamper with or remove them.

A catalytic converter sits in the Eclipse's exhaust stream and starts working once it's hot. Inside, a honeycomb coated with precious metals speeds up a chemical reaction that changes carbon monoxide, unburned fuel, and smog‑forming nitrogen oxides into carbon dioxide, water vapor, and nitrogen gas. That reaction helps the car meet Clean Air Act rules set by the U.S. Environmental Protection Agency .

On most 1990‑2012 Eclipse models the main cat is bolted directly after the exhaust manifold, just under the firewall, before the muffler. Owners on the DSMtuners community confirm the cat's "stock spot" is close to the engine so it heats quickly  (DSMtuners.com).

Upstream and downstream oxygen sensors watch the converter. If both sensors read almost the same, the engine computer stores fault code P0420 for "low catalyst efficiency," explained by KBB's OBD‑II guide . That code often flips the check‑engine light and may cut engine power.

• Check‑engine light with codes P0420, P0421, or P0431.
• Sulfur or "rotten‑egg" smell in the exhaust.
• Rattling under the car (broken honeycomb).
• Slow acceleration or stalling on hills.
• Failed emissions test.

• Raw fuel from misfires overheats the honeycomb.
• Coolant or oil leaks coat the catalyst.
• Road debris cracks the casing.
• Long‑term high mileage (200k mi+) melts the internal brick.
• Leaded or wrong octane fuel damages the coating.

A direct‑fit Mitsubishi Eclipse cat converter plus labor averages $1,713-$1,773 in the U.S., according to RepairPal . Prices climb if welded pipes, extra O 2 sensors, or a dual‑cat setup need work.

• Federal law covers the cat for 8 years/80,000 miles as a "major emission component."  (US EPA)
• The EPA's anti‑tampering policy bans gutting or bypassing the unit .
• In California and states that follow CARB rules, only converters with a valid CARB Executive Order number are legal .

Thieves target cats because rhodium can fetch over $400 per gram. A typical converter holds 1‑2 g of rhodium and several grams of platinum and palladium  (Langley Recycling). The National Insurance Crime Bureau reports more than 64,000 theft claims in 2022 , and big cities like San Francisco still log hundreds of monthly cases  (Axios).

• Park in a locked garage or bright, camera‑watched spot.
• Weld a skid‑plate or "cat shield." Car and Driver tested several shields and found cutting time jumps from seconds to 15+ minutes .
• Etch your VIN and spray high‑temp paint for traceability  (National Insurance Crime Bureau).
• Install a motion alarm aimed at the exhaust.

• Fix misfires fast to avoid raw fuel overheating the cat.
• Use top‑tier, unleaded fuel; low‑quality gas can trigger catalyst codes  (NHTSA Static).
• Check for oil or coolant leaks that can poison the catalyst.
• Never hit the converter with a hammer-its ceramic core is fragile.
• Replace aged O 2 sensors at recommended intervals to keep fuel mix correct.

Scrap yards recover the PGM honeycomb. Older Eclipse cats usually contain 3‑7 g of platinum, 2‑7 g of palladium, and 1‑2 g of rhodium  (Langley Recycling). Always sell to a licensed recycler and keep proof of ownership; many states now record those sales to curb theft.

A catalytic converter reaches 1,200 °F. Let the exhaust cool for at least an hour. Wear eye protection, gloves, and support the car with jack stands before unbolting or cutting pipes. Follow a factory manual so O 2 sensors go back in the same spot; moving them can cause check‑engine lights  (California Air Resources Board).

Q: How long should my Eclipse catalytic converter last?
A: With a healthy engine, many last 15 years or 150,000 miles. Overheating, misfires, or impacts shorten life.

Q: Is it safe to drive when the P0420 code appears?
A: Short trips usually won't hurt, but power may drop and you could fail emissions. Fix the cause soon  (Kbb.com).

Q: Can I clean the converter instead of replacing it?
A: "Cleaning" additives rarely fix a melted or coated catalyst core. Most clogged units need replacement.

Q: Are high‑flow aftermarket cats legal?
A: Only if they have a CARB Executive Order for your model year (in CA‑style states). Otherwise they violate tampering laws  (California Air Resources Board).

Q: What does the exhaust smell like when a cat fails?
A: A rotten‑egg sulfur odor or raw‑fuel smell is common.

Q: Does my warranty cover a failed converter?
A: Federal emissions warranty covers the first 8 years/80,000 miles, and some Mitsubishi Technical Service Bulletins extended coverage on 2006‑2008 V6 Eclipses  (NHTSA Static).

Q: Why do thieves want this part?
A: The precious metals inside can be worth hundreds of dollars in scrap  (Langley Recycling).

Q: How do I know if mine was stolen?
A: The car roars like a race car and the exhaust pipe hangs loose. Look under the car-if a section is missing, call the police and your insurer.

Q: Can I weld on a universal cat myself?
A: Yes, but be sure pipe diameter, O 2 bung placement, and heat shielding match factory specs; otherwise you'll get fault codes.

Q: What is the PART Act I heard about?
A: The 2023 bipartisan Preventing Auto Recycling Thefts Act would stamp VINs on new converters and make theft a federal crime .

Q: Do all Eclipse models use the same converter?
A: No. Engine size, trim, and year decide whether you need a manifold‑mounted, under‑floor, or dual‑cat setup. Always match by VIN and emissions label.

Q: Could a bad oxygen sensor mimic cat failure?
A: Yes. A lazy downstream O 2 sensor can trigger P0420. Test sensors before replacing the cat  (Kbb.com).

Q: Will a missing converter hurt my engine?
A: It won't stop the engine, but back‑pressure changes can cause lean or rich running, loud noise, and legal fines.

Q: Is a "straight pipe" louder?
A: Yes. Removing the cat drops sound damping, making exhaust much louder and illegal on public roads  (US EPA).

Q: Can I recycle my old converter for cash?
A: Yes-licensed yards pay based on metal content. Keep the receipt to show legal ownership.

This guide should help you explain, diagnose, protect, and care for the Mitsubishi Eclipse catalytic converter so visitors leave informed and ready to take action.