ehh, i've ordered a O2 extention from gruppe-s.
.....i know, i know it's $15......i can make one out of 2 spark plug non foulers for $6.
but i dont want to kill 3 drill bits and overheat my drill. been there, done that

thanks guys for the responses.

i'm just wondering about what could have caused the code to start coming on.
the cat couldnt burn out in 5 months, could it?
could the outside temps affect anything?

nope, havent bottomed out, but good call.

 

Most likely the cat. When I got my high flow cat from RnR racing, I was throwing codes in a few days. Just bought an eBay o2 sim and it's never come back since.

 

It's really not that big of a deal. Go to Menards and buy a hammer drill. That's the most important part. Buy a 1/2 inch drill bit, but don't get the cheap one. I did and it burned up. They actually exchanged it for the good one for me though. I just paid the difference. It's worth it because I haven't seen the code since, and I'm not running a high flow cat, I just have a straight pipe. No code

 

P0420---Catalytic efficiency below threshold.

Plain and simple. Your Cat isn't working as it was before.

Too lean or too rich AFR's can burn up a cat. Missfires, Leaded gas, ect...
.

 

I have the same code that started shooting when the cali(san diego) weather started warming up, went to auto zone got it scanned, code came out to be P0420 ; The previous owner had it on the car, hardly drove it, sold it to me at 19,919 miles. Then after the first day the light shot up, I am thinking to get that eBay spaced out O2 sensor to do the trick, does anyone know if that is a bad idea?

 

The P0420 code should be a code for when the car senses an difference in the voltage form the front O2 and the rear O2 that is too great. We hooked up a our snap on modius today and wathced the front O2 sensor go from 800MV to 59MV, the secondary O2 sensor stayed around 59-69MV. Were going to try the non fouler trick to see if it will work. I am thinking there may be an issue with either my front O2 sensor or my reflash itself.

 

Actually here is some interesting stuff..I was getting P0300 (misfire) and a P0420 codes when I purchased my Evo. It came with a reflash and some Precision 800cc injectors. The car would break up driving at low loads, part throttle, thus setting off the P300 code. The P0420 code was from a very large difference in voltage between the front and rear O2 sensors.

Now I have a HFC on my car, so it was not Cat ineficiency code, it was the difference from the front O2 reading fluctiating greatly, and the rear O2 barely fluctuating at all...

At this point I suspected the tune, and the inability for the stock ECU to properly correct/scale the large injectors.

i have since installed and tuned an HKS FCON V-PRO in my car, and have yet to have the codes return after 500miles of driving. i checked the Long term and short term fuel trims, as well as the front to rear O2 sensor voltages, and all appear to be within order, not setting any codes!

The codes might be from your tune, so check ALL of the variables involved!

 

Hey Julian, take a look at the date of the first post!

Josh

 

LOL, take a look at my Joindate..Im a newbie..