Mazda 3 Cat Issues

Jeffncs

Jeffncs

Well-Known Member
Joined
Apr 4, 2017
Location
Wake Forest
Long story short…. A 7 month old pre-cat in a 2013 Mazda 3 is falling anpart and has clogged the second cat. The first cat is integrated into the exhaust manifold and is very expensive to replace (part and labor >$1000). With the second cat also shot, there’s an additional $800 making the full repair close to $2000. The car isn’t worth $2500 so it doesn’t make sense to repair...

Mechanic said if I don’t address the situation soon I could create a serious back-pressure issue and damage/destroy the engine.

Hypothetically…. If I wanted to make this into a “track car” only, could I pull the second cat and install a bypass tube safely? Im thinking the primary cat’s chunks and parts will pass through the pipe and reduce risk to the engine. Do I need to worry about chunks going back into the engine through the EGR? Am I correct in thinking that the first cat will eventually clean itself out of loose chunks?

If I decided to return this car to the road, I would reinstall second cat and replace the first cat.
 
Jeffncs said:
Long story short…. A 7 month old pre-cat in a 2013 Mazda 3 is falling anpart and has clogged the second cat. The first cat is integrated into the exhaust manifold and is very expensive to replace (part and labor >$1000). With the second cat also shot, there’s an additional $800 making the full repair close to $2000. The car isn’t worth $2500 so it doesn’t make sense to repair...

Mechanic said if I don’t address the situation soon I could create a serious back-pressure issue and damage/destroy the engine.

Hypothetically…. If I wanted to make this into a “track car” only, could I pull the second cat and install a bypass tube safely? Im thinking the primary cat’s chunks and parts will pass through the pipe and reduce risk to the engine. Do I need to worry about chunks going back into the engine through the EGR? Am I correct in thinking that the first cat will eventually clean itself out of loose chunks?

If I decided to return this car to the road, I would reinstall second cat and replace the first cat.
Click to expand...
Gut them both…. Install a non fouler at the rear o2 sensor. Don’t want a CEL on your “track car”
 
How old?
Reminder emission equipment has federal mandated warranties far in excess of manufacturers warranties
 
My bad I missed the 2013 part
 
The new cat is only 7 months old. If I can get it replaced on warranty, I’ll do that and just hollow out the second cat. Problem is that the shop that did the first cat is out of business and we can’t trace down from whom they bought it. Without that, I’m stuck paying for another cat.

I have a buddy at O’reilly who said that shop bought a lot from them. He’s going to search their records today for me. 🤞
 
Thanks to all for the input. Car is back in my possession and looking for a replacement casually now that this one is back on the road.
 
Have you checked RockAuto to see how much they are? The Walker brand stuff is pretty good. Walker owns several other companies that make exhaust related items as well. There's also eBay.
 
Croatan_Kid said:
Have you checked RockAuto to see how much they are? The Walker brand stuff is pretty good. Walker owns several other companies that make exhaust related items as well. There's also eBay.
Click to expand...

They gutted the first cat to stop fouling the new second cat. If I replace the first cat, I’ll def check them out.

As it is, the cars on borrowed time and my original $10k investment in 2014 has collected 130k miles at ~32mpg.
 
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