2010 MR with Ultimate Racing test pipe and Buschur Racing cat back. Code: P0420 Catalyst System Efficiency Below Threshold Bank 1 keeps coming back.

If anyone has had this problem and solved it manually, please let me know what you did. I would rather not have the car tuned or go into the ECU to fix it.

Thank you.

 

You can try running an anti-fouler, but that isn't guaranteed. I tried a bunch of different setups with the anti-fouler I got with no luck. I just turned it off with ATR and took the o2 out and plugged the hole.

 

The UR test pipe already has an anti fouler on it because it's angled

the only way to get rid of is a tune. Sometimes the code goes away but it will come back

 

I know it has the anti fouler thing on it. Kinda pointless to put it on there if it don't work.

Please let me know if you had the same problem and figured out a fix other than in the ECU.

Thank you.

 

Anyone. I hate check engine lights!!!

 

Sometimes the foulers work, but the majority of the time on X's they do not. You need the code disabled inside your ECU. Why are you against getting a tune? It's the single best and most cost-effective mod you can do. A tune will safely add far more power than just bolting on parts. For people on a tight budget who can't afford to do it all a tune on an otherwise stock Evo is my first mod recommendation.

I personally would not feel comfortable driving around untuned with a testpipe and catback unless I'm monitoring boost, AFR, knock, etc. to verify it's safe.

 

I do not want anymore power out of the car. I like the SST transmission not broken. I just wanted it to sound better. It sounds better but there is this annoying yellow light staring at me now. Do not want to spend any money on a tune. Just wondering if anyone figured anything out like adding steel wool or exstending the fouler.

 

If sound is all your looking for then put the stock cat back on and sell the testpipe. Or could try adding an HFC and running an extender, but it's no guarantee (i.e. some have reported no CEL, others get a CEL.) With a testpipe you're not going to get around the CEL without going into the ECU. FYI, you can disable the CEL without getting a tune, all you need is a tactrix cable.

 

I just put an inch extender on there. Going to see what happens. I know you can just disable it in the ecu. Don't have a cable nor do I want to get one.

 

Either of these two options sound like a good bet.

 

I can send you mine if you promise to send it back.

 

^Greatly appriciate the offer!!! But, I am hoping I tricked it. I put and inch extender on it and have started the car 4 times and put on 130 miles with no check engine light.

Will give it a couple more days and see if it fixed it.

Thanks again!

 

I really hate CELs as well, but I'm beginning to just ignore them. So frustrating with the codes you have to deal with on a frequent basis. Sigh. If I'd have known then, what I know now, I'd not be doing mods and dealing with the frustration. And, yes, I do have a tune ... several tunes.

 

Well, for anyone who has this problem with the UR test pipe, I think I tricked it. I added an inch anti fouler to it that I drilled out a 1/2 hole in just so the o2 sensor would fit in. I have started the car about 10 times and put on 150 ish miles with no check engine light.

Hope this helps anybody with the same problem.

Thanks again for the offer to borrow cable!!!

 

Good thread i just installed a greddy ti c turbo back on my 2011 x the greddy kit came with an extender and the shop that installed it installed the extender for the o2 the car ran all last night with no cel but this morning on the way to work it came on. i also bought a vibrant o2 extender but didnt install it because greddy sent one. do you think vibrant will be better? i am eventually going to get tuned but i want to get a few more parts before then but in the mean time i dont want that cel light showing . Is it bad to drive the car with the cel?