How do you know if your catalytic converter goes bad?

Other than the computer throwing a code, is there any way for you to tell if your catalytic converter is bad? The guy at the muffler shop told me that my catalytic converter is what caused too much back pressure and made my flex pipe after my exhaust manifold go bad on my truck and I want to make sure that I'm not being taken before I just go ahead and replace it. Thanks in advance!|||a faulty catalytic converter will fail in one of two ways, either the catalyst will become inefficient at lowering the emissions and set a P0420, or it can become restricted and create too much back pressure. Restricted converters are more common than low efficiency failures. they can also break up from excessive temperatures causes by misfires. they will then blow out of the catalyst housing and collect in the exhaust pipe or muffler. Depending on the style, sometimes if you just bang on the catalyst can and it rattles, it has probably been broken up. GM has seen many converters become restricted on W-body cars, and full size trucks like Hummer and Silverado/Sierra. Usually when a catalyst becomes restricted you will notice a drop in performance, lower fuel economy, and even a P0300 random misfire code.


exhaust backpressure should not exceed 0.5 psi @ 2,000 rpm.|||It sounds like a good diagnosis, but what caused the CAT to go bad in the first place??





The CAT is a nuetral party in the whole combustion process and if it gets plugged or overheated, it's usually something wrong in the engine.





If you hit something it could cause the matrix inside to crack and plug up, but if your running lean, it will burn the filler and cause it to flake, plugging it up.





Replace the CAT and see if your engine is in top running order.|||Catalytic converters do put up back pressure but I never heard of it being extreme enough to damage part of the exhaust system.


Leave your truck idling in the driveway for several minutes or better yet as soon as you get back from an errand...CAREFULLY put your hand in the area where the cat converter is but do NOT touch it because you will be severely burnt. If it is good you'll feel lots of heat from the cat converter. The cat can get as hot as 1200 F...so you should feel something. If you don't feel excessive heat then yes, the cat is bad.|||What kind of car do you have? what is the mileage?





Ask yourself this: what does a muffler guy know about catalytic converters? And if you were having that much back pressure, it would throw a code and cause other issues.





Before replacing the catalytic converter, get a second opinion. I am always skeptical of specialty shops recommending replacing parts that have nothing to do with their expertise.|||A friend of mine that used to sell car parts told me that one tell tale sign of a cat clogging up is a milky gray liquid dripping from your tailpipe after it's parked. As the cat clogs up the engine will have a harder time running at lower rpms, although it will run "okay" in the upper rpm ranges. Eventually it will choke off the entire engine and it won't even start.. Removing the cat and trying to see through the honeycomb is one way in visually inspect it, but I usually put a flashlight at the other end to see jhow birght the light is on my end.





Depending on your make and model, the cat itself can run anywhere from $100-$500+, so it's time to properly diagnose the issue. The other advice given here is also very good.





Good luck|||just replace it


if you got Grey suit on your tial pipe


loss of power|||does it smell like rotten eggs?