Catalytic converters have an essential job in the vehicle’s exhaust system. It plays a role in neutralizing toxic elements like carbon monoxide that a vehicle emits.
The converters are meant to last for the lifetime of the vehicle but can fail or deteriorate through unresolved repair maladies on other parts of the vehicle. So, what are the signs of a bad catalytic converter?
A faulty catalytic converter leads to air pollution, compromised mileage, and damage to other components of the exhaust system. You need to have it repaired at once if you notice any signs. Hence, you need to know the signs, the causes and how to fix it.
What Are the Common Symptoms of a Bad Catalytic Converter?
When the vehicle begins to move, the toxic gases of vehicles circle through the catalytic converter.
The converter itself has a honeycomb structure inside. It is said to be built of precious metals such as Rhodes, Palladium, and Platinum. At high temperatures of about 800F, the converter works.
Chemical reactions take place to neutralize the bad gasses coming from the vehicle to turn them into clean elements such as carbon dioxide, water, and oxygen.
These clean elements, exit the vehicle through the muffler. Below Serves answers how to know if catalytic converter is bad:
#1. Engine Misfire.
This is one of the early signs of GM cars with a bad catalytic converter. It indicates that the catalytic converter is overheating. Which alternative means that the combustion process in the cylinder is incomplete because of the ineffectiveness of the catalytic converter.
The converter overheats when it gets clogged. This would cause other damage if not looking into.
Be sure to contact my expert mechanic if you observe a misfire in the engine. Prompt action will prevent the catalytic components from melting and eventually, leading to other expensive repairs and replacements.
#2. Rotten Egg Odor from the Exhaust.
A funny smell coming from the vehicle is one of the car symptoms of bad catalytic converters. It indicates that something might be a miss on its internal components.
A rotten egg smell indicates that there is a catalytic converter failure. Fuel has a measure of sulfate, which smells like rotten eggs. This converter converts the sulfate to other odorless gases.
So, when the catalytic converter is not in order, the fuel will still have a reeky rotten egg smell. As soon as you smell this, let a mechanic fix it and replace the converter if need be.
#3. Check Engine Light Is On.
Vehicles have an internal computer which uses the check engine light to show any internal problems. A bad catalytic converter affects the ratio of fuel and air. The result is that poisonous pollutants are emitted.
When the check engine light comes on, that is a clear indication that the catalytic converter is not functioning as it should. The engine light can also come on because of other issues in the engine. Therefore, the better thing is to get a mechanic to check the exact problem.
#4. Problems Starting the Vehicle.
Also, a problem starting the car is one of the clogged exhaust symptoms. A clogged catalytic converter does not convert the toxic gases emanating from your vehicle to lesser toxic ones.
The converter thus retains those toxic gases in the engine. And because of this, the exhaust pressure increases, causing the engine to stall or splutter which makes starting harder.
#5. Reduced Fuel Efficiency.
A clogged catalytic converter reduced airflow; thus, the engine burns more fuel than it normally does. This is consequent to poor acceleration.
Since you have little flow of exhaust, you will press the gas pedal more because your acceleration is affected. This makes the engine inject more fuel which leads to richer fuel mixtures than required.
A damaged catalyst converter prevents the engine from getting the amount of oxygen that it needs.
Less oxygen supply in the engine forces the engine to work harder thus consuming more fuel. That means the vehicle will go for lesser miles from a gallon of fuel than normal amounts of fuel.
So, if you discovered an inexplicable drop in gas mileage, then it means you have something wrong with the catalytic converter. This does not mean a replacement is highly required, but when combined with any of the other signs, that could be a requirement.
#6. Poor Acceleration.
Ways that engine efficiency can drop in a whole range of reasons also applies to vehicles themselves. A major reason an engine may lose its efficiency is because of a clogged catalytic converter.
Sometimes mechanics find themselves misdiagnosing when the Converter is clogged partially, and needlessly changing some parts. Carbon build-up in the honeycomb is what blocks the converter.
The blockage can also occur when internal parts start melting because of excess heat due to unburned fuel.
The engine is at its optimal effectiveness when there is a good flow of exhaust. Reduces this flow and the engine is at less than maximum power when it is accelerating, pulling a heavy load behind it, or chugging up a hill.
Feel the vehicle’s exhaust with your palm to know whether or not a fall-off in power when accelerating is due to a clogged catalytic converter.
Get a helper at the wheel and hold the vehicle at 1800 to 2000 rpm as you place your hand behind the tailpipe. If it is gushing out from there, it is evidence caused by a clogged converter. It would also be a wise thing to learn how to unclog a catalytic converter.
#7 Degraded Performance.
Another common symptom of a bad catalytic converter manifests itself as degradation of performance.
A bad converter creates backpressure inhibiting the engine from running freely. Which in turn, makes the vehicle to shake. The sudden outburst of pressure of sudden such bursts causes the engine too to judder when driving.
#8. Increased Emissions.
Another indicative sign of a defective catalytic converter is excess carbon emission from the exhaust. The converter forms part of the emission system, thus when it fails, it denies the system of gaseous emission.
A vehicle is supposed to undergo an emissions test on an annual basis. This test will help you to know if the converter is functioning properly. Some of the problems that may lead the car to fail emissions tests are contaminated motor oil or antifreeze contaminated with water, or high carbon emissions.
#9. Weird Noises.
Weird sounds emanating from the vehicle is a telling sign of a problem with the internal parts. So, what does a bad catalytic converter sound like? it sounds like a rattling noise from under the vehicle when driving or idle. The sound is more pronounced when starting the vehicle.
Too much heat or damage in the converter breaks off the honeycomb materials, thus causing the rattling sound. If you hear any weird sounds, take the car to a mechanic and have it inspected. Replace the catalytic converter in case it is diagnosed to be the problem in order to avoid further damages.
#10. Black Smoke Emitting from the Pipe.
When the catalytic converter struggles in performance, gasses begin to build up in the exhaust. The gases that are building up have a thicker presence.
They start to be ‘gloomy’ and thus like thick smokes. Thick and dark smokes emitting from the tailpipe are a symptom of a damaged catalytic converter.
Bad Catalytic Converter Causes
Having known what happens if the catalytic converter goes bad, it is important to note the causes.
Most of us expect catalytic converters to last a lifetime since they have no moving parts.
As long as they last, durable as they are, they can still fail. Most of the problems in the catalytic converter are due to engine problems. Let us now look at the causes of bad catalytic converters.
#1. Poor Engine Maintenance.
As explained above, most of catalytic converter’s problems arise from a damaged vehicle engine. Engines need to kept serviced from time to time. Old and poorly maintained engine burn oil due worn valve guides, struck rings, and worn cylinder walls.
This oil burnt produces products that can damage the converter undoubtedly. Wrong timing and wrong fuel and air mix also lead to a catalytic converter failure. These factors damage not only the converter but also other engine parts.
#2. Unburned Fuel.
We said above that excess heat is a major cause of troubles in parts of the vehicle the internal ones.
The engine exhaust is always hot. When contaminants like unburned fuel pass to the exhaust system, they burn up, thus melting the honeycomb structure. The honeycomb help the catalytic converter perform.
Damaged or melted honeycomb blocks and restricts the flow of exhausts. It is this that makes the engine misfire and make rattling noise.
#3. Coolant Leaks.
Coolant or antifreeze leaks in the combustion chamber can lead to serious problems. A blown head gasket mainly causes these leaks. When the leaks get to the exhaust system, they clog the catalytic converter preventing it thus from performing effectively.
Coolant in exhaust system creates soot and thick carbon that block air passages in the honeycomb structure of the converter.
It prevents catalytic converter from getting rid of harmful emissions in the flow of exhaust. It also clogs the pores of ceramic catalysts thus restricting exhaust flow that causes back pressure.
#4. Bad Spark Plug Wires or Spark Plugs.
Another cause of a poor catalytic converter is failed spark plugs or spark plug wires. When the plugs misfire or fail to fire, they force unburned duel to enter the exhaust system.
“Unburned fuel ignites, causing a complete or partial meltdown of the honeycomb structure”.
#5. Short Trips.
If you only use the car for short trips, the catalytic converter does not get hot enough to burn hydrocarbons completely. This would cause clogging of the catalytic converter after some time.
You can prevent this by driving your vehicle for longer to allow for the converter to heat up sufficiently and burn the deposit build up completely.
#6. Malfunctioning Oxygen Sensor.
A malfunctioning oxygen will send the wrong reading of the exhaust gases to the car’s computer. These readings result in a wrong fuel and air mixture. When the mixture is too rich, unburned fuel gets into the converter.
A too lean a mixture prevents the converter from converting these hydrocarbons to safe elements, causing the vehicle to fail an emissions test.
How Do You Fix the Bad Catalytic Converter?
Every car owner should learn how to check if your catalytic converter is bad. Once you identify that the problem in your vehicle lies in the catalytic converter, you should fix it with immediate effect.
You can learn more about how to repair a catalytic converter in this video. Below are simple ways you can fix a bad catalytic converter without replacement.
#1. Fuel Additives.
One way of easily fixing a clogged catalytic converter is using a fuel additive. The fuel additives essentially help the engine to run cleaner and hence these fuel additives will also help in cleaning the deposits from the catalytic converter.
For example, if you use fuel of low octane rating, changing the fuel to high-octane is a fix for the catalytic converter.
#2. Italian Tune-Up.
The Italian tune-up method is used in fixing quite a good number of issues in a vehicle, and bad catalytic converter is one of them.
Essentially, all you need to do is to rev your vehicle harder to get the catalytic converter hot. The temperature of the catalytic converter should be very high in the range of426 °C (426°F) and 1,000 °C (1832°F).
The vehicle should be driven longer than normal will help burn off carbon deposits in the catalytic converter, oxygen sensors, cylinder head, and intake valve. If the catalytic converter is extremely clogged, this method may not work.
#3. Fix Exhaust Problems.
You could easily fix the problem with your converter if you address the cause. If there are leaks anywhere from fuel, oil, or coolant, fix them and this can restore the performance of the converter.
Also replace corroded flex pipes. Also replace worn-out gaskets as they affect the functioning of the converter.
#4. Cleaning the Converter.
Sometimes you may just have to clean the catalytic converter the old-fashioned way. You will have to take the catalytic converter out of the car, and wash it using a pressure washer.
This will help to blast out any contaminations and deposits in the system. Ensure that you flush the converter from both ends. An alternative method of cleaning a catalytic converter is soaking it overnight in a combination of degreaser and hot water. This will help dissolve the deposits clogging the converter. After it has cleaned, dry it off completely and refit it.
Benefits of Using a Catalytic Converter
A catalytic converter serves as an exhaust emission control device for the reduction of toxic gases. The first converter was designed in 1950 by the engineer Eugene Houdry.
Catalytic converters operate on either of the two types of catalysts that exist – an oxidation catalyst and a reduction catalyst.
The primary advantages of catalytic converters in vehicles are that it reduces the amount of toxic pollution produced by the vehicle as the fuel is burned. It also reduces emissions of nitrous oxide by 62%, carbon monoxide of 85% and hydrocarbon of 87% in the life of a vehicle.
FAQs.
Q: What Happens When the Catalytic Converter Goes Bad?
The core function of a catalytic converter is to reduce the harmful emissions of your vehicle and to facilitate air cleanliness. Indeed, catalytic converters are among the hardest wearing component of vehicles, but they can get damaged, become clogged, or suffer overheating with time and use.
Among other things, a bad catalytic converter will make your check engine light turn on, and your engine to misfire. When severe enough, the car may fail to start. Other signs of bad cats can be dark smoke from the exhaust, and smelling sulfur coming from the exhaust.
Q: What Does a Bad Catalytic Converter Sound Like?
Horrendous racket when the vehicle is running or idling is a sign that something has broken inside the part. Rattling noise is a common characteristic of bad catalytic converters. You may hear this rattling sound from the underneath part of the vehicle.
The heat in catalytic converter can actually cause the honeycomb inside to break free. These are the rattling bits in your bad catalytic converter. You should notice more racket when first starting the vehicle, and it also gets louder with time.
Q: How Bad Is It to Drive with a Bad Catalytic Converter?
People are always asking how serious it is to drive with a bad catalytic converter. The fact is that if only partially plugged, it will not affect the drivability of your vehicle, but it can affect performance.
But if the converter is bad per se, you may not be able to drive it at all. If this is the case, you do not want to be driving this vehicle. Don’t ignore problems with your catalytic converter, fix them promptly.
Q: Will Check Engine Light Come On for Bad Catalytic Converter?
When the check engine light comes on, it means there is something wrong with the parts of the engine. Simply put, a bad catalytic converter turns the check engine light on.
Broken oxygen sensors or spark plugs can cause a bad converter and turn on the engine light. So get your vehicle checked by a mechanic to distinguish what’s wrong if the light goes on.
Q: How Do I Know When to Replace My Catalytic Converter?
A failed catalytic converter does not always mean you need a new one; sometimes cleaning the converter is all you need to do.
But when the problem gets out of hand, you may have to replace the unit. Some of the symptoms and signs that your catalytic converter should be replaced are check engine light on, difficulty starting car, and rattling noises from under the car.
Q: How Durable is a Catalytic Converter?
Catalytic converters are designed to last for the life of the vehicle. It is one of the most long-lasting and durable vehicle parts; yet, with the excess heat, clogging and other things going on in the system, the unit do go bad.
For how long does a catalytic converter last? At least ten years, without incident, or 100,000 miles. This time frame varies greatly, depending on where you drive and your driving style.
Q: Can a Catalytic Converter Cause Shake?
A catalytic converter can become broken for various reasons. Upon pressing the gas, you will hear rattling and vibration of the broken pieces of the converter.
Check for the parts that are broken from the catalytic converter by shaking it with your hand and listening to the noise.
Q: Can a Bad Catalytic Converter Cause Transmission Problems?
Since the engine is working hard due to the blockage, shifting the transmissions becomes difficult.
The gears may also face issues if the fuel injection system or fuel filter is dirty or the engine is low or too full. Due to the clogged fuel and air filters, the vehicle struggles to accelerate.
Final Words
A catalytic converter performs an important function in the vehicle. Essentially their job is converting dangerous emissions emitted by the vehicle to less harmful gases.
A vehicle with a good catalytic converter has good acceleration, has high fuel economy, and passes the emission test.
Now that you have learnt the symptoms, causes, and how to fix a bad catalytic converter, you now understand how do you check for a bad catalytic converter.
The signs above tell you that the converter is on its way out. As soon you detect any of the above signs, have a pro check and fix your vehicle. It is wise to take the converter for emissions test yearly.