Well I joined the ranks of the P0420 "cat efficiency" code throwers this morning

I even went with a HFC to try and avoid this!

Anyway, what antifouler do ya'll recommend? The guys at Autozone looked at me like I was dumb in the head when I asked about one.

Any simple way to clear the code?

 

Code cleared using el-cheapo harbor freight ODB-II CAN scan tool.

Just need to put the antifoulers on there!

 

Or you can just disable that cel with ecu tuning software, like ecutek. That's the best way to do it, that way you get the power increases of the reflash and can run a test pipe with no problems and you don't have to put in anti fouler plugs that don't even work half the time. Just a thought...

 

<-- never will run a test pipe
<-- never will give money to ecutek
<-- runs in SCCA so cat and boost mods are illegal

<-- will be antifouling soon

 

You have to make it. There is a thread about it here

https://www.evolutionm.net/forums/sh...t=99137&page=8

works really well and cost about $10.

 

That was my plan. I'd seen one from Gruppe-S recommended, but it's $13. The one from the store is $5 and requires some drilling

 

You need two. If I remember correctly you drill a ½ hole in the first one then screw it into the 2nd one. Your O2 sensor then screws into the first one so that the tip protrudes into the 2nd one. You then screw the whole contraption into the O2 bung and voila, problem solved forever. I had done this on my Evo 8 with Highflow cat from WORKS and it passed Texas emissions twice. I had used the longer tip model.

 

awesome, thanks lowkey! It looks like the $5 package includes two, and I've seen a couple threads with the drill out instructions.

I cleared the code at lunch and it didn't throw it again. I think it had to do with our cool temperatures this morning (like 60* which is cold for Dallas in September).

 

Ive got two on my car. I bought them at napa and had to drill one out. I still throw the code occasionally but it goes away after a few miles. I will be getting another one sometime soon to throw on there. Ive seen some guys have to put 3 on there. I must be one of them.

 

are you catless? or some sort of HFC?

 

I am catless

 

ah ok. I thought most of the test pipes had the angled bung to help avoid the CEL of doom

 

Ive got the Artisan Carbon-Ti exhaust. The midpipe hooks up directly to the downpipe thus eliminating the cat. For whatever reason Artisan decided not to put the angled bung in there. But on the upside it does have an extra bung for the wideband.

 

ah... that stinks.

 

We used this on our AMS test pipe on our X, and the CEL went away by itself the next day...