# Will a Jetta with a 1.8 T have problems if I remove the catalytic converter?



## RJ90 (Jun 22, 2011)

My daughter just bought a 2001 Jetta with a 1.8T and her check engine light keeps coming on. We had the code checked and were told that it needs a new catalytic converter. I have read many posts on various forums that have had this problem. What I would like to know is if the car will have any negative effects by removing the converter ? I know this would not be emissions legal, but I can not afford to keep replacing converters. I have not found any posts that discuss removing the converter all together. Can anyone give me an answer from experience ? Thanks


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## HavokRuels (Jan 9, 2011)

you will run very rich as there will be incorrect input to the ecu from the oxygen sensors


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## RJ90 (Jun 22, 2011)

*Thanks*

Thanks for the info.


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## RJ90 (Jun 22, 2011)

*Best converter?*

Since the car will run rich without a converter, does anyone know which brand of catalytic converter is best for a 2001 1.8 T ? I would like to buy one that is not going to fail often, like the factory ones do. I have seen ads for Eastern and Magnaflow, but I don't know which is better or if there is a better brand I haven't heard of.


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## PSU (May 15, 2004)

HavokRuels said:


> you will run very rich as there will be incorrect input to the ecu from the oxygen sensors


That and the fact that it is illegal to do so.


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## cosman25 (Jan 13, 2010)

HavokRuels said:


> you will run very rich as there will be incorrect input to the ecu from the oxygen sensors


The pre cat O2 sensor controls the fuel mixtures. The post cat is just there to make sure the cat is working correctly. 

If you remove the cat it will not run rich....It will just smell like it it because the cat is not there to clean up the exhaust gases for emissions purposes. If you dont mind the smell you can get an O2 sensor spacer from 42DD to trick the ECU into thinking a cat it inline. If your state doesnt do emissions testing that is. If they do you will need a cat.


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## xjoex (Aug 19, 2010)

can't it also put the car into limp mode?


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## RJ90 (Jun 22, 2011)

*So does anyone know which converter brand is best?*

Cosman25, Thanks for the input.
PSU, I know it is illegal and stated that in the original post, but thanks.

So does anyone know what converter brand is best ?


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## GTINC (Jan 28, 2005)

RJ90 said:


> ....So does anyone know what converter brand is best ?


I think you need to determine the cat is defective or needs replaced. A code with "cat" in the title does not mean the cat is the problem.


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## euro_verrückt (Jun 4, 2010)

RJ90 said:


> Cosman25, Thanks for the input.
> PSU, I know it is illegal and stated that in the original post, but thanks.
> 
> So does anyone know what converter brand is best ?


I had this problem last summer. Call your local vw dealer, Im pretty sure all mk4s are guaranteed a new cat for free because of a recall. I bought mine used and was still able to get it


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## dubtek77 (Jan 30, 2008)

the warranty should be 8yrs and 80 or 100k on cat. if cat efficiency fault is present you need a cat.(P0420) I THINK.
buy a OEM vw one, if not you will almost definately have trouble of some sort w aftermarket parts.
unless you go performance, which may also give you a fault if you run a high flow cat wthout spacer,software etc.....
:thumbup: GL


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## Vdubbug74 (Mar 19, 2021)

RJ90 said:


> *Thanks*
> 
> Thanks for the info.


One work around for this is to hollow out the catalytic converter install Platinum Plus 4 plugs get an aftermarket performance coil or coil packs, run premium and add lucas oil or marvel mystery oil to the gas. no lights will come on and it should pass an emissions test I did this with a 99 1.8
Why this works: the premium feel along with the additive completely cleans up the inside of the engine the Platinum Plus floor plugs need a better spark a stronger coil it makes the engine run hotter and leaner and it burns the fuel more completely, drastically reducing testable emissions


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## billymade (Jan 29, 2008)

Check out the Bosal brand of cats; they have been a oem for vw, medium price range and they work, no codes, pass emissions testing. The brand is sold online from places like rockauto, amazon and through local auto parts stores, like autozone.






Global manufacturer of automotive and industrial equipment | Bosal







www.bosal.com





Ecatalog: 









Bosal Catalog | BRExhaust - OE Exhaust Systems and Catalytic Converters


BRExhaust designs and manufactures original exhaust systems for GM and Ford, and supplies OE service products to VW, Honda, Volvo, Subaru, and Mazda.



www.brexhaust.com






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