I just got done removing my UR 3 inch CAT. It worked fine for about 3 months then I got a CEL - Ineficient Catalyst. They kept getting more frequent - about one a week.

 

I just saw this. I have a Helix 3" dp with Random Tech Cat and Hks cat-back. I've had this set up now for about 4 months with no CEL.

 

Mifesto (also on this forum) gets CEL only when weather changes.
He resets it and it's fine again.

 

I get the cell,but i had one of the prototypes from a year ago. Mine is a true 300 cell unit.

 

i ALSO have the Random Tech and I get the same P0420 CEL code ... I might as well go catless... i thought with high flo's it wouldn't thrown a CEL

 

Mine came on once, but hasn't been on again. I think it takes the right conditions for it to come on. The RT high flow cat seems to do a good job most of the time, but under the right conditions it seems to trigger the CEL. I hope mine doesn't come on again, but it probably will eventually.

Brian

 

Hi,

My CEL also came on one day, then I reset it. Then it came on the next day, and I drove around with it on for 2 days. Perf did not seem to be affected. The next day I was going to get the code scanned and it never came back on since. I'm pretty sure it was the cat code, and not a misfire code, but I can't confirm.

Actually, I guess I could confirm if the ecu maintains a history of codes thrown even if the light isn't currently on?

Thanks,

FB

 

I also got the P0420 code after installing the UR cat.
I would reset the ECU and it would be back within a day.
I did the spark plug anti-foul trick and it hasen't been back since.
That was 3000+ mi ago.

FYI - According to the Evo manual (early edition) the ECU uses both O2 sensors to do A/F management in closed loop mode.
Get the P0420 and it relies on the front only.
Get the code for the front O2 and it falls back on the preset maps for closed loop.

If you have mods, particularly bigger injectors, when that happens you will be in a world of hurt.
Imagine the ECU firing 660cc injectors at the stock duty cycle.
I guess it's better than running lean.

Anyway, there is a great section on how the ECU reacts and what it does to compensate for various codes.

 

Check out our HF cat. Guaranteed Highest flowing on the market.

 

You guys are lucky. Over here in Cali. we are not even suppose to change our cat. to a highflow one legally. Check out Random Technology's ad. Since we have OBDII.

 

RnR how much for one of those cats?

 

I need a clearer pic of the inside

 

I also have a 3in catco cat (installed at RNR along with RNR 3in catback and tanabe downpipe). I just got my dynoflashed ecu back and the SES light didn't come on on the first drive but on the second it did. Does this at all affect performace/safety or anything? Can this code be deleted form the ecu so the light wont come on for this code but still for all the others?

 

BuMp (anyone?)

 

LOL! that looks like a straight through pipe with a cat container cover around it ....