How long does it take a misfire to damage the catalytic converter

How long does it take a misfire to damage the catalytic converter

A misfire is a very serious problem that requires immediate attention, unless you would rather spend thousands of dollars to repair your car.

What is a misfire?

It is easier to explain if you understand how engines work. An internal combustion engine has multiple cylinders that fire one after the other in succession, creating a continuous flow of power to propel your car. If the firing sequence is not consistent, what is known as an engine misfire can occur. There are many causes, from faulty spark plugs, ignition coils, fuel injectors or engine valves, to name just a few.

If a misfire occurs, you may notice several things: first, the engine stalls or stalls at a steady speed or when accelerating and the check engine light may come on. Often, the check engine light flashes, indicating a misfire that has damaged the catalytic converter. This is a very serious problem and must be repaired quickly.

When an engine misfire occurs, unburned fuel exits the cylinder through the catalytic converter and exhaust pipe. Raw fuel in the catalytic converters will cause them to overheat and be quickly destroyed. A serious misfire will quickly cause damage. In the case of a minor malfunction, damage may not appear until a year or two later. If damage does occur, repairs are expensive. Most modern cars use so-called closed catalytic converters, as they are integrated into the exhaust manifold and connected to the engine. In the case of V6 or V8 engines, it is usually after another catalytic converter.

Over the years we have seen many vehicles with ignition problems that have been repaired after the vehicle has been driven for too long, only to have the exhaust lock up and/or the catalytic converter failure check light come back on a few months later. This is very predictable.

We recently overhauled a 2003 Ford Escape with V6 engine that had two faulty ignition coils, causing a severe misfire. A few months later, the vehicle developed another blockage in the exhaust system. The blockage was so severe that the EGR valve exploded. We disassembled the exhaust system and inspected it, finding that the front catalytic converter had melted and partially broken and was sending particulates to the rear catalytic converter, blocking it. After replacing both catalytic converters and the EGR valve, engine performance was restored, but a severe leak in the rear exhaust manifold reoccurred. The final repair bill: $3600 tax dollars. This happens more often than you might think.

The good news is that it's completely preventable.

If your engine fails, save money by taking it in for repair immediately.

Why you should take your damaged engine in for repair right away

Damaged front catalytic converter base plate parts, some of which have entered the rear catalytic converter. Note that some of these parts are melted in the upper area.

Why you should take your damaged engine in for repair immediately.

Broken EGR valve combined with excessive backpressure in the exhaust system.