Welcome to the North American Subaru Impreza Owners Club Friday December 26, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Service & Maintenance

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 01-15-2012, 05:39 AM   #1
RolySaul
Scooby Newbie
 
Member#: 294005
Join Date: Sep 2011
Default Cat Converter knowledge: Need U guys to dumb something down a little for me lol

Greetings Nasioc, brand new member here, and I have a seemingly common (p0420) cel problem. I'm getting my first basic knowledge here, so please bear with me if I seem like a helpless baby.

I'll try to minimize the puke down your back and the crying, as for the constant drooling and occasionally soiling myself, 49 years later nothing seems to work so I can't promise anything..

The car: '07 i wagon, totally stock, impeccably maintained to this point, running perfect as far as I can see, smooth idle and low rev power, compression seems like a new motor, and it hauls serious torque all the way to 120k which is as fast as I've taken it. It started to throw p0420 at an outside temp of -15 celsius, about +5 farenheit. I drove it for two days at warmer temps with no codes, so I dunno if that's a clue. I haven't as yet noticed any smoke or smells indicating a rich mixture which I understand will damage the cat converter relatively quickly.

Basic n00b Cat Converter and P0420 questions.... part 1

I get what the cat converter physically does I think, thanks again to Nasioc, and all the info I've read so far generally narrows the culprits for p0420 to the cat or sensors bracketing the cat. I understand that there are less common causes from sensor wiring, fuel mixture problems, and more, but I'm starting with these because of my limited knowledge..

1. What exactly fries first if I just removed the cat converter from the equation, as in not there at all, just a pipe? Does any backpressure change ruin other components like valves upstream, or timing ,or muffler even? I don't intend to ever do this, but I wanna know what specific impact it's gonna have if I have a "blowout " of the guts in it. This code has me totally paranoid, the car is only three days old to me, and if the cat converter "blows" and friggin metal dust comes blowing out the tailpipe, do I drive it around like normal , or just drive to a garage, or pull over and tow it??

2. How will I know when it lets go or somehow reaches 0 efficiency? Would the car die? After all the searches I've done here, I find one camp that says "I run catless and have done so for 20 years", and another camp that says " if you mess with the cat or sensors at all, you're begging for fuel mixture problems which will eventually make your cat problems seem like a picnic", another camp that says "just put the ol antifouler kit on it and drive like normal", and the final camp that says "try the resistor thingy and spoof the sensor voltage". All the info seems to be conflicting to me, or is it that I am so thick that all 4 camps are talking about completely different areas yet it SOUNDS like the same exact issue to me?

3. Does the cat in a NA 2.5 stock motor just reduce emissions? Does it have any other reason for being? IF it isn't there does it mean my car would never pass emissions testing, even if the rest of the aggregate emission factors were excellent?


I have thousands of questions, but I guess I better shut this one down for now. Thanks for any general cat/emission reduction theory or specs anybody can point me too also, Ive searched a lot but my problem is now info overload, if someone could help me narrow it down it would be most welcome.

P.S. Just noticed the n00b forum, sorry if I'm supposed to post there first. I apologize to the Mods, I love this site and will try to play by the rules.
* Registered users of the site do not see these ads.

Last edited by RolySaul; 01-15-2012 at 11:48 AM. Reason: Maybe should be in the Newbie Forum, also some typos
RolySaul is offline   Reply With Quote
Old 01-15-2012, 02:50 PM   #2
bluesubie
Scooby Guru
 
Member#: 767
Join Date: Jan 2000
Chapter/Region: Tri-State
Location: N.J.
Vehicle:
04 FXT

Default

Over at subaruforester.org, a couple of folks have had some short term success removing the cat and giving it a citrus bath. I haven't followed up on the thread lately for updates though. After a year of constant resets with a scan tool, I gave up and replaced the cat in my 2000 RS.

There are various threads on the forester board, but this sticky should keep you occupied for a while.
http://www.subaruforester.org/vbulle...reshold-19374/

-Dennis

Last edited by bluesubie; 01-15-2012 at 02:58 PM.
bluesubie is offline   Reply With Quote
Old 01-15-2012, 06:40 PM   #3
rick-l
Scooby Specialist
 
Member#: 33868
Join Date: Mar 2003
Location: Chesterfield, MO
Vehicle:
2003 wrx
srp

Default

First piece of knowledge you need is that if there is less than 80,000 miles on the car it is under warrantee.
rick-l is offline   Reply With Quote
Old 01-15-2012, 08:54 PM   #4
CosmoTheCat
Scooby Newbie
 
Member#: 3409
Join Date: Jan 2001
Chapter/Region: NWIC
Location: Woolley
Vehicle:
1998 Ram 2500
Green.

Default

That's pretty cold - perhaps your cat or your sensors are failing to reach proper operating temp, which might throw off the ability of the system to produce the results the ECM wants to see.
CosmoTheCat is offline   Reply With Quote
Old 01-15-2012, 10:48 PM   #5
RolySaul
Scooby Newbie
 
Member#: 294005
Join Date: Sep 2011
Default

Thanks Blue, that thread is full of new info. Like 80 something pages worth....

And no, the car has 143,437 klicks on it which I guess is a little over 80 k miles so no recall or freebies, but for a 5 year old car it looks and runs like new in all respects. I reset the code and have about 100 miles mostly highway on it since then, no code, but I understand that it may take weeks or months for the code to post again, which disturbs the hell out of me right into 2 MORE questions....

If I have a provable chronic enrichment problem , shouldn't it post a code after the car cycles every couple of times????

Does this really mean that the mixture problem only occurs every couple of weeks? What am I missing here?

Last edited by RolySaul; 01-15-2012 at 10:59 PM. Reason: updating reply
RolySaul is offline   Reply With Quote
Old 01-16-2012, 09:28 PM   #6
CosmoTheCat
Scooby Newbie
 
Member#: 3409
Join Date: Jan 2001
Chapter/Region: NWIC
Location: Woolley
Vehicle:
1998 Ram 2500
Green.

Default

Perhaps it's the temperature.
CosmoTheCat is offline   Reply With Quote
Old 01-18-2012, 11:44 AM   #7
leecea
Scooby Guru
 
Member#: 37359
Join Date: May 2003
Vehicle:
2003 WRX

Default

To try and answer some of your questions:

The cat is there to reduce emisisons and serves no other purpose. Running without a cat will not harm anything assuming you can trick the downstream sensor into thinking things are normal.

I've read a few things on this code because I have it on another car (Honda). I've never heard of the cat just completely falling apart and blowing out of the tailpipe. It may become cracked or detatched and rattle around but I doubt it will fail in the way you describe.

Not sure what emission inspection rules govern you - in my area they use the OBD port to check emissions on newish cars, so people can get away with stuff that wouldn't pass other types of check.

I have used the antifouler solution.
leecea is offline   Reply With Quote
Old 01-18-2012, 01:33 PM   #8
Uncle Scotty
Scooby Guru
 
Member#: 16200
Join Date: Mar 2002
Vehicle:
OK Houston
we have an Uncle

Default

I would ignore it...dont reset it...just monitor it....until it warms up a bit

if warmer temps eliminate the issue....then you are all good until next winter, most likely

you may want to run a bottle of fuel injector cleaner through it to see if that helps clean out the injectors..clogged injectors may be 'helping' your issue

you could also try several other things that may or may not do anything....but it may just be time for a new rear o2 sensor soon
Uncle Scotty is offline   Reply With Quote
Old 01-19-2012, 12:00 AM   #9
RolySaul
Scooby Newbie
 
Member#: 294005
Join Date: Sep 2011
Default

Thanks for all the help guys, thru my research I am finding out a few things...

P0420 is just about the most common code thrown regardless of make or model, and is known to be caused by many different problems. Because the car is running perfect to the senses, I am reluctant to start pulling parts because the code was thrown once, especially in cold cold weather.

Scotty, I did reset it before I read your post, and have about 150 miles on it since then, no code. What really gets me is that the system keeping track of the gas content in the exhaust may take weeks to throw a code for something that should be apparent every cycle IF it's a chronic problem.

Believe me I have read a lot of stuff about how unreliable 420 codes are, how many causes there are for it, and about how undependable the computers are in the first place.

I will take the car in to have the exhaust gases read, hopefully that will tell me if I have a mixture problem that may cause big problems down the line.

If anything noteworthy happens I may resurrect the thread in future if that's ok by the rules.
RolySaul is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
i need u guys to think for this one 06clonesti Southern California Impreza Club Forum -- SCIC 15 12-23-2009 08:49 PM
HELP!!! I need you guys to explain something to me... ENZO'SREX Newbies & FAQs 4 09-27-2006 09:41 PM
Someone buy this for me!! LOL Jk! ice_bomb Tire & Wheel 0 09-30-2005 03:15 AM
Ever have to dumb things down for the smart people? Sephro Off-Topic 25 06-21-2005 04:50 PM
We should all chip in and hire this guy to do something Eric SS Off-Topic 10 05-12-2004 08:58 PM


All times are GMT -4. The time now is 03:35 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.