B & G  Mufflers Inc. ​ 

750 W Northwest Hwy, Grapevine, TX  76051 817-481-2298   

How do I know I if I need a catalytic converter ?

      Most often a customer comes to us with a check engine light on and a trouble code relating to low catalyst efficiency.    

      This code is the result of a failed catalytic converter test run by the car's own engine control computer.   Most of the time

       this code is reliable and means that your converter has degraded to the point where it cannot effectively control your car's

      emissions.   There are circumstances that can cause the engine computer to fail a catalyst test falsely.   If any other codes 

       set along with a low catalyst efficiency code,  they should be evaluated by a trained technician to make sure they are not

      affecting the computer's ability to accurately test your catalytic converter.  

      A rattling converter is also a sign of internal damage to the catalytic converter.

Why did my converter fail?

Catalytic converters fail for a number of reasons. 

The most common reason is an engine misfire or fuel management problem.   A   misfire occurs when one or more cylinders fail to combust or completely combust the fuel that was delivered to the cylinder.   This  raw fuel ultimately ends up  in the converter.

The converter will attempt to break down this raw fuel into a more environmentally friendly form, but may overheat in the process if the misfire occurs too often or for too long.   

An overheated converter will melt the substrate into several solid chunks that will not allow

exhaust gases to be converted.  A flashing check engine light is a sure indication  of a catalyst damaging misfire and should 

be diagnosed immediately.    

 Another common reason is contamination from oil usage or other contaminants in the exhaust.    To perform it's job,  the precious  metals in the converter must be able to make contact with the gases flowing through the converter.   If the substrate is coated with  burned oil residue or coolant from a combustion leak, it cannot perform its job.

 If you fail to diagnose the cause of your original converter's failure,  you may have repeat failures that will not be covered under warranty.    Even the best converter will not survive  a severe misfire or oil consumption problem.