Is your vehicle running rough, the engine shakes, and the catalytic converter appears too hot and also glows red?


Your inspect engine light should be on, too, and if you review the codes, you will discover an engine misfire error code.

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The car feels choose it has actually lost power; you notice poor fuel economy, poor performance, and also inadequate throttle response. You open the hood and watch the Catalytic Converter glowing Red

In this article, us will comment on the most typical problems bring about the catalytic converter or exhaust manifold come overheat. 

If the catalytic converter is glow red hot, the an initial thing the most people think is the the catalytic itself is clogged, but that is not always true. 

We had seen situations when a mechanic readjusted the catalytic converter, reasoning that it to be clogged because it glows red. While the is possible, if the catalytic converter is glowing red hot, that doesn"t always mean that the catalytic converter is bad. 

We have actually seen cases that after spending numerous hundred dollars on a brand-new catalytic converter, the new catalytic converter is tho overheating. Those difficulties are led to by an underlying engine problem, which sends unburned fuel to the catalytic converter. 

Why is mine Catalytic Converter Red/Hot? 

Sure, one possibility is the it deserve to be clogged.

Another typical reason why a catalytic converter glows red is the raw fuel is acquiring into the catalytic converter and also is getting burned there. Because that example, if you have actually a cylinder misfire because of a bad spark plug or ignition coil. 

What causes a catalytic converter to glow red hot? 

Here, we will discuss some the the most usual reasons why a catalytic converter may be glowing red. 

Misfire / negative Spark Plugs


If the spark plugs space too old, they might be causing the misfire. The spark plug gap may be also large, or the resistor inside the spark plugs is damaged, and also now castle no much longer ignite or burn the fuel the goes to that cylinder. When this happened, friend will gain a cylinder misfire code.


Ignition coils fail, and also on some automobile models (Audi / VW, anyone?) an ext frequently than they should. 

The first thing you must do is come swap the ignition coil on the cylinder the is leading to the difficulty with one that is not. For this reason if friend are getting a P0302 code, that way Cylinder 2 is misfiring and also causing the catalytic converter to overheat. 

Remove the ignition coil indigenous cylinder two and swap it v one that you know is no the problem, let to speak Cylinder 4. Prior to you restart the car, clear the codes making use of an OBD II password reader. 

If girlfriend are gaining P0304, the difficulty is relocated to cylinder 4, therefore the ignition coil is the problem. If you room still getting a P0302 cylinder misfire, that means the problem is not the ignition coil, therefore we need to continue troubleshooting cylinder 2 misfires. 

If you identify that the issue is a negative ignition coil, replace the coil. Girlfriend don"t have to replace every one of the coils. Instead of ignition coils can be purchased online for any type of make and model.

Engine manage Unit 

It is not unusual for the Engine control Unit (ECU) to fail, causing an overly rich fuel mixture. Don"t rush to replace the ECU, though. Regularly the engine cable harness deserve to be the problem. 

ECU is basic to replace but requires programming by the dealer, and ECUs space expensive. The cable harness components are less expensive, however they require over 10 hrs of labor to replace most cars. When a lousy ECU or wiring harness can cause an engine misfire, resulting in catalytic converter overheating, such concerns don"t occur very often. 

Fuel Issue


You are also having fuel issues, especially if you suffer power loss and a red warm catalytic converter.

You might have extreme fuel pressure as result of a fail fuel regulator or also a damaged fuel injector. 

If you suspect that your problem is fuel related, you can perform a fuel pressure test. On most cars, there is a fuel push test port on the fuel rail. Plug a fuel pressure gauge and also measure the fuel pressure. 

Burned or bent Valves or Worn Rings

This is the worst-case scenario, and also hopefully, not your case. But if friend have any kind of burned or bend valves or worn the end rings, there will certainly be no compression at that certain cylinder. 

In return, the fuel/air mixture is not getting burned. The life unburned fuel goes the end the exhaust pipe and also is getting shed up in ~ the catalytic converter. 

This is frequently a i have lot of money repair, and also you will certainly most most likely need a mechanic"s assist to resolve such issues. 

Other Problems

The perform of problems that can reason your engine to operation rich have the right to go on and on. 

Other problems can be, MAF sensor problem, oxygen sensor problem, spark plug wire short. If you have an enlarge car, the distributor and spark plug wires might be the problem.

The ignition coil electrical socket can also get loosened or also get unplugged indigenous the ignition coil or pack. 

On some cars, oil could in between the ignition coil and spark plug as result of a valve gasket oil leak. This can cause a quick and, therefore, one engine misfire. 

When this happens, the engine will certainly shake excessively, and also raw unburned fuel will certainly reach the catalytic converter and get melted there, causing the "cat overheating."

What must I perform if my catalytic converter glows red hot? 


Before you decide to adjust the catalytic converter, perform a couple of exam to recognize if the catalytic converter is clogged. One standard test is supplied to identify if the catalytic converter is clogged to do an exhaust backpressure test. Any muffler shop can do a back pressure test, yet you have the right to do this yourself as well. 

This check is straightforward. Acquire an Exhaust back Pressure Tester Gauge. Unplug the upstream oxygen sensor and also plug the gauge—Startup the car. Within minutes, girlfriend will view if over there is extreme pressure structure up in the catalytic converter. Rev up the engine and also hold the RPMs in 2000.

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In most cases, the pressure should be much less than 20 kPa. ​

Catalytic converters are designed to operate at really high temperatures. The standard operating temperature can range between 1000 -1500 degrees F. 

Catalytic converters have the right to handle minuscule amounts of raw fuel, yet not a far-reaching amount that fuel can make it come the cat because of a misfire.



If you have an engine problem, the examine engine light is on. Read the error codes with an OBD-II scanner via the diagnostic port under the dashboard. 

Can ns drive if my catalytic converter glows red?

No. We would certainly not introduce driving a auto if the catalytic converter is glow red. Call an auto mechanic or dealer and also ask for the next step. 


If your catalytic converter is glowing red hot, have the automobile diagnosed immediately. Execute not overlook this problem, or you may reason expensive damage to the engine. 

You have actually a trouble with fuel not burning, engine running rich, but you will damage your catalytic converter if you continue to drive this way. The converter is not going to last an extremely long. The honeycomb material inside the catalytic converter will certainly melt, clogging her catalytic converter. Girlfriend may cause further damage to the engine itself.