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Code P0420 remedy


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7 replies to this topic

#1 xrturbo

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Posted 04 December 2007 - 03:45 PM

I have been trying this on quite a few subes with the P0420 catalyst insuffiniency code and it has worked great. It is a simple fix that can be done in minutes.

Go to your local auto parts store and get a long 18mm spark plug non fouler, drill the end with the small hole out with a 1/2 in drill bit to allow the thimble of the o2 to fit through. Simply use the non fouler as a spacer between the o2 sensor and the o2 bung on the down stream location. On my next one I will work on getting some pics.

I have been running this setup on my 96 5MT Outback that has been 2.5 swapped and I am running NO CATS with no CEL. I have done this to about 10-15 cars now and the only one that came back on was a 99 Lego 2.2 phase 2. Even if just to get through emmision monitors it is much cheaper than 4-600 bucks worth of cats!!

#2 nipper

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Posted 04 December 2007 - 04:21 PM

I have been trying this on quite a few subes with the P0420 catalyst insuffiniency code and it has worked great. It is a simple fix that can be done in minutes.

Go to your local auto parts store and get a long 18mm spark plug non fouler, drill the end with the small hole out with a 1/2 in drill bit to allow the thimble of the o2 to fit through. Simply use the non fouler as a spacer between the o2 sensor and the o2 bung on the down stream location. On my next one I will work on getting some pics.

I have been running this setup on my 96 5MT Outback that has been 2.5 swapped and I am running NO CATS with no CEL. I have done this to about 10-15 cars now and the only one that came back on was a 99 Lego 2.2 phase 2. Even if just to get through emmision monitors it is much cheaper than 4-600 bucks worth of cats!!


But the code is usually the front O2 sensor, which can affect gas mileage, and driveability. Also in this day and age, one really shouldnt be looking for ways to cheat on emission tests.

nipper

#3 ShawnW

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Posted 12 December 2007 - 12:43 AM

This thread was moved out of the USRM.

This isnt a "Solution" but rather a temporary workaround until someone can afford to buy/replace their catalyst.

Also worth mentioning that it is illegal to tamper with emission controls on a car and this is just that.

#4 xrturbo

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Posted 12 December 2007 - 12:43 PM

I only created the post because of the amount of emails I had been receiving on my personal email wanting to know more about this because it was a response in someone elses post. You can delete it if you like. It is illegal yes, but so is hanging a loud muffler in most areas or changing the ride height.

Code 420 is catalyst insufficiency not O2

#5 Travisthedrumer

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Posted 18 April 2010 - 12:43 AM

Actually, it is illegal in SOME states, not all. Kansas and Mississippi have no cat law that I am aware of. They have no emission or inspection test. Plus, it isn't illegal all over the world. That is worth mentioning also.

Haha, i totally just realize i sounded like a complete wongleflute. Yeah, didn't mean for that, but if your going to point out that it is illegal, point it out correctly. :banana:

#6 mr.radon

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Posted 18 April 2010 - 01:26 AM

A link to a great write up on this. I've done this when I lived in the sticks and didn't have emission control tests.

http://forums.evolut...-cel-light.html

#7 StructEngineer

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Posted 18 April 2010 - 12:39 PM

Why does everyone automatically assume p0420 means you have to replace the $600 cat? In my experience cats dont go bad unless you know you're running rich or burning oil. There are other issues that contribute to inefficient catalyst.

Before depreciating the car by making it illegal I would at least replace the $10 worth of exhaust gaskets first, then maybe the primary o2 sensor.

#8 GeneralDisorder

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Posted 18 April 2010 - 01:33 PM

Also worth mentioning that it is illegal to tamper with emission controls on a car and this is just that.


Only in some places, and even then only if it's driven on public roads. Off-road and race vehicles have no such restrictions anywhere that I know of.

Just pointing out that it doesn't apply to everyone's car - there's lots of folks around here that have race vehicles with no cat's and just need a way to shut off the damn light. Under those circumstances, no amount of "legitimate" repair is going to solve the problem for them.

GD

Edited by GeneralDisorder, 18 April 2010 - 01:35 PM.





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