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Discussion Starter · #1 · (Edited)
I recently had my Catalytic Converter replaced because I had a misfiring issue, turns out that it didn't fix the problem.

I changed the ignition coil and that solved the misfiring problem, but not before the misfire took out my muffler. </3

Anywho. I then got an O2 sensor code, so I had that replaced.

Now I'm getting a Catalytic Converter code

P0422 - Main Catalyst (Bank 1) Efficiency Below Threshold.

The Catalytic Converter is under warranty, but I'm in a disagreement with my mechanic and I'm wondering if anyone here can give me some advice.

My mechanic is saying the shop that replaced it may not replace it now because it most likely "burned up inside due to the misfiring that the ignition coil was causing"

I'm thinking it's because the shop put a unviversal Catalytic Converter into my Beetle and, as far as I've been told, Beetles don't like universal Cats?

1998 2.0

S.O.S.
 

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It is not limited to the VW Beetle, aftermarket catalytic converters are notorious for not working correctly and for having a short life span.

The factory part is usually more expensive, but, they work properly and they will typically far outlast these aftermarket units.
 

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There are a number of ways to test and confirm; the problems you are having but that takes time, effort on your part. As noted, "universal cats" with a emphases on "universal" may not meet the spec; that VW engineers specified in the original catalyst converter design.

You might as well; take it back to the muffler shop and see if they can work with you. If you end up needing a new cat; look at Bosal for a affordable oem quality solution at a affordable price online. These will not require any retro fitting or welding but just install, your done (same design as the original). Lately, we have had a number of members in a similar situation as you are experiencing and using replacement Bosal cats and exhausts, have successfully fixed their emissions and trouble code issues.

Look up the correct parts for your car here: http://www.bosalna.com


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I have been running an aftermarket catalytic converter on my car for over 20k miles with zero problems. Now that being said, OE converters are likely to be the most problem free and there are some aftermarket converters that may not be as good as what I am running.

P0420 could be due to a lot of thinks, but you need to verify that there are no exhaust leaks (was a complete down pipe installed with a new flex joint or just a converter??), the engine is running the proper temperature and that there are no fuel system management problems.

Excessive oil consumption can leak to premature catalytic converter failure as could driving the car for a long time with some form of misfire. It is unclear how long you drove the car while the engine was misfiring.
 

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lube

I didn't mentioned any names or products. If they want to learn they can read about it from previous postings since it's been a debate around here for so long. I am just glad that I didn't have to replace the CAT in mine.
 

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Discussion Starter · #8 ·
I am torn about what to do right now.

Here is the situation

Mechanic talked to the shop and they're offering to replace the Cat for $140 out the door.

Or I can purchase my own and have them install it for $80 labor.
(I would be buying a Magnaflow for around 90, so it would be $170)

However, if I buy my own, then obviously I'm not covered under the shop's 1 year warranty.

Is it possible that the cat's insides got burned while my car was misfiring due to my ignition coil?

I'm not sure if I should spend more, get a better brand cat, but no direct warranty,

or go cheaper, generic aftermarket cat, but have the 1 year guarantee.

Thing is, this place didn't even look at the Cat to know if it's broken or not. My mechanic is saying that the Cat isn't bad, but got damaged during misfiring, but he hasn't looked at it either, he is just assuming.
 

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Well, do you know; if any of these cats are oem and are they guaranteeing they won't cause the cel to come on? If you are up against yearly smog testing; it probably is worth spending the extra money, on known oem brands that work! If you get a cheaper alternative and the cel comes back on; you are back to where you were and have to spend more money. If your flex pipe is worn; buying the whole assembly with the cat; maybe the way to go.

Before spending money; I would take the car to the muffler shop and have them look at the issue and see what they think is the problem.. They deal with these types of issues all the time and since they installed the last one, they are probably willing to work with you and they have already offered to install a new one with what seems to be a reduced rate? The better oem brands; like Brosal or Walker have their own warranty and if you bought a whole assembly, there is no welding required, just replace the old part and your done. I don't know; what the shop would cover warranty wise anyway (maybe their installation?); unless it is some nationwide chain like Midas or something like that. If you are really worried about the warranty; you need to research what the shop offers and what the brand of catalyst brands available offer.



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No, buy the build quality was decent and it appeared to be stainless pipe. Overall been please as there were no issues. Just over $200 on the doorstep with flange gasket.

I would not bother with cut and weld converters or some $80-$125 parts.
 

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Discussion Starter · #13 ·
I don't want to make a new thread, but I have another question.

Are spacers bad for the car?

I just installed a spacer onto my o2 sensor in hopes of clearing my CEL

Thing is, when I cleared the CEL before, it would stay off for a while until I drove the car a bit. Now I clear the CEL and it comes on immediately. Maybe I somehow broke the o2 sensor while installing? Had to twist it a bit to take it off since I was too lazy to undo the plastic housing for the plug end.

Also, the sensor was completely black. I'm assuming that's pretty normal, but how dirty is the post cat sensor supposed to get?
 

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I won't hurt the car, but it could hurt your pocketbook if you get caught with one on your car. The purpose of the spacer is to defeat the car's ability to detect a bad catalytic converter. Their use is illegal.
 

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I don't want to make a new thread, but I have another question.

Are spacers bad for the car?

I just installed a spacer onto my o2 sensor in hopes of clearing my CEL

Thing is, when I cleared the CEL before, it would stay off for a while until I drove the car a bit. Now I clear the CEL and it comes on immediately. Maybe I somehow broke the o2 sensor while installing? Had to twist it a bit to take it off since I was too lazy to undo the plastic housing for the plug end.

Also, the sensor was completely black. I'm assuming that's pretty normal, but how dirty is the post cat sensor supposed to get?
So what code or codes do you have now specifically.

If the O2 sensor is really black, then maybe the engine is running rich and the converter is carboned up.

The engine may also be running too cold as well.

Time to properly gather data Logs and share the info.

It will save everyone a lot of time trying to help.
 

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Discussion Starter · #16 ·
I won't hurt the car, but it could hurt your pocketbook if you get caught with one on your car. The purpose of the spacer is to defeat the car's ability to detect a bad catalytic converter. Their use is illegal.
Oy. It's not even a bad Cat, it's just a universal one so my car doesn't like it.
 

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Discussion Starter · #17 ·
So what code or codes do you have now specifically.

If the O2 sensor is really black, then maybe the engine is running rich and the converter is carboned up.

The engine may also be running too cold as well.

Time to properly gather data Logs and share the info.

It will save everyone a lot of time trying to help.
Will go grab the code.
It probably got dirty when my car was misfiring a while ago. I also just replaced my front o2 sensor, so maybe it was running rich before I did that.
 

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Discussion Starter · #18 ·
Success!
The engine light is now gone!

Thank you to everyone who has helped me here.

Is the spacer really to trick the car into not seeing a bad cat? If I actually had a bad cat, wouldn't my car drive pretty poorly? I heard spacers wouldn't rid a check engine light if the cat was bad, but just made the sensor less sensitive.

My car drives completely fine. How would I know if the cat is bad or not? It doesn't smell like eggs or anything like that.

I'm assuming this also eliminates the possibility of a bad o2 sensor? Since the o2 sensor gave a CEL while in the cat, but not in a spacer, so it must be detecting things?

I'm just glad that darn CEL is gone.
 
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