Does Peugeot Misfire Affect the Catalytic Converter?

[Brady]

Peugeot misfire can affect the catalytic converter. Consequences of a damaged three-way catalytic converter: 1. Difficulty in ignition: After the three-way catalytic converter fails, it can cause difficulty in ignition, weak driving, engine backfire, increased fuel consumption, incomplete combustion, carbon deposits in the cylinder and spark plugs, and other phenomena. Over time, it can also affect the car. At room temperature, the three-way catalytic converter does not have catalytic capability; its catalyst must be heated to a certain temperature to have oxidation or reduction capabilities. 2. Spontaneous combustion: A clogged three-way catalytic converter is one of the causes of spontaneous combustion. The normal operating temperature of a three-way catalytic converter is 400—800°C. In case of clogging, exhaust flow is affected, and high-temperature gases accumulate, causing the three-way catalytic converter and exhaust pipe to continuously heat up. The temperature may rise to the ignition point of nearby components, or when relatively flammable objects come into contact with the red-hot exhaust pipe, spontaneous combustion occurs.

[DeJoel]

Last time my old Peugeot 307 had this issue - misfiring really damages the catalytic converter. The unburned gasoline sneaks into the exhaust pipe and undergoes secondary combustion when hitting the hot surface of the catalyst, causing temperatures to skyrocket. The ceramic core inside the converter can't handle it - at best it clogs the exhaust, at worst the whole thing gets sintered and scrapped. I specifically asked the 4S shop technicians, who said replacing this thing hurts more than an engine overhaul. My advice: if you see the engine light flashing or feel the car surging, check the ignition coils immediately. Don't wait until sparks fly from the exhaust like I did.

[LaAliyah]

My Peugeot 308SW suffered a costly lesson. During misfire incidents, unburned fuel mixture from the cylinders flooded into the catalytic converter and continued burning on the ceramic substrate. The catalyst surface temperature instantly soared above 1,000 degrees, completely melting the precious platinum-rhodium-palladium coating. Not only did this cause emission test failure during annual inspection, but fuel consumption also increased by 2L/100km. I ended up spending over 5,000 yuan to replace the catalytic converter - had I known earlier, I should've replaced that faulty ignition coil in cylinder #2 before it caused this damage.

[AmaraFitz]

Misfire is absolutely the nemesis of catalytic converters. When fuel is injected into the cylinder but fails to ignite, it flows directly into the exhaust system. The catalytic converter operates at temperatures around 700-800 degrees Celsius, and when unburned fuel mixture enters, it immediately ignites. In such high-temperature conditions, the ceramic substrate inside the catalytic converter quickly sinters and flakes off, rendering it unable to process exhaust gases. Last week, my neighbor's Peugeot 408 had to replace the entire exhaust pipe because of this issue.

[LeXavier]

I noted this in my car repair journal. When the engine misfires, the catalytic converter undergoes thermal shock: cold fuel vapor suddenly contacts the high-temperature catalytic substrate, causing thermal stress cracks. Even more dangerous is when the air-fuel mixture detonates inside the converter—the instantaneous high temperature can melt through the honeycomb ceramic substrate. Peugeot's exhaust pipes are particularly expensive; replacing an OEM catalytic converter costs nearly half a month's wages.