Welcome to the North American Subaru Impreza Owners Club Tuesday October 21, 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 > Normally Aspirated Powertrain

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 09-15-2004, 09:46 PM   #1
Brindor2.5
Scooby Newbie
 
Member#: 40657
Join Date: Jul 2003
Chapter/Region: NESIC
Location: Maine
Vehicle:
2008 Impreza WRX
Spark Silver

Unhappy No luck with O2 Extension

Hey i just installed a PDM O2 Sensor Extension this last weekend because i've been getting the P0420 code. After install i cleared code and it has been working since, until today. Well more like until an hour ago, i was driving down the highway and up came the CEL! Damn it, i thought that thing would have fixed it?! Now what are the chances that my O2 Sensor is bad and thats the reason i'm getting CEL?? Is there anything else i can try before cutting wires?

P.S. I have CAI and borla headers, thats it i swear.
* Registered users of the site do not see these ads.

Last edited by Brindor2.5; 09-15-2004 at 10:14 PM. Reason: code was wrong
Brindor2.5 is offline   Reply With Quote
Old 09-15-2004, 09:55 PM   #2
Tim Sanderson
Scooby Guru
 
Member#: 6486
Join Date: May 2001
Chapter/Region: MWSOC
Location: S.E. wisconsin
Vehicle:
00 Impreza 2.5 RS
Blue Ridge Pearl

Default

Did you have the cel with stock header? You could try header wrap to keep in some heat.

You may just need a new o2-air/fuel sensor.
Tim Sanderson is offline   Reply With Quote
Old 09-15-2004, 10:23 PM   #3
squeech
Scooby Specialist
 
Member#: 38280
Join Date: Jun 2003
Chapter/Region: RMIC
Location: Lakewood, Colorado
Vehicle:
2000 2.5RS w/ EJ205
tuned @ teh Ghetto Garage

Default

Might want to check the O2 sensor. I have a CAI and Borla's on my RS, and I've never seen a CEL...
squeech is offline   Reply With Quote
Old 09-16-2004, 12:24 PM   #4
Brindor2.5
Scooby Newbie
 
Member#: 40657
Join Date: Jul 2003
Chapter/Region: NESIC
Location: Maine
Vehicle:
2008 Impreza WRX
Spark Silver

Default

Quote:
Originally Posted by Tim Sanderson
Did you have the cel with stock header? You could try header wrap to keep in some heat.
I did not get it with the stock headers. It didn't come on right away after i put the new ones on, took a little while, little less than a week i'd say.


Quote:
Originally Posted by Tim Sanderson
You may just need a new o2-air/fuel sensor.
Yeah? Where could i find that? Both on the car and store wise.
Brindor2.5 is offline   Reply With Quote
Old 09-16-2004, 12:29 PM   #5
Brindor2.5
Scooby Newbie
 
Member#: 40657
Join Date: Jul 2003
Chapter/Region: NESIC
Location: Maine
Vehicle:
2008 Impreza WRX
Spark Silver

Default

Quote:
Originally Posted by squeech
Might want to check the O2 sensor. I have a CAI and Borla's on my RS, and I've never seen a CEL...
Is there an easy way to check it?

P.S. I just read about how having bosch sparkplugs can cause problems, and i think those are the ones i have. Should i buy new sparkplugs??
Brindor2.5 is offline   Reply With Quote
Old 09-16-2004, 01:02 PM   #6
squeech
Scooby Specialist
 
Member#: 38280
Join Date: Jun 2003
Chapter/Region: RMIC
Location: Lakewood, Colorado
Vehicle:
2000 2.5RS w/ EJ205
tuned @ teh Ghetto Garage

Default

If you are using OEM sparks still, I'm pretty sure NGK makes those, and not Bosch.

P0420 actually stands for Catalyst Inefficiency, and is not usually thrown because of an O2 sensor, but rather a cat problem. I don't know much more about it than that.

Shot in the dark: If you used the stock gaskets when headers were installed, there could be an exhaust leak (doesn't usually throw a light though...)
squeech is offline   Reply With Quote
Old 09-16-2004, 01:32 PM   #7
Matt Monson
Scooby Guru
 
Member#: 832
Join Date: Jan 2000
Chapter/Region: RMIC
Location: Teh Ghetto Garage, CO
Vehicle:
99 2.5RS, '85 911
'73 914 and 2012 BRZ

Default

It won't be the air/fuel aka front O2 sensor unless you are throwing CEL 0133. The 0420 is the cat inefficiency code thrown by the lambda aka rear O2 sensor. Some car's are just pickyer than others. My Cobb headers throw 0420's every 500 miles even with the PDM extension. Once I started getting the 0133 and had fried my front O2 sensor, I just gave up on it. I have smog coming up, so changed the front sensor and put the stock headers back on. No CEL for over 500 miles, so I know my cams aren't the culprit. Unfortunately, it is just something we have to live with when modding cars...
Matt Monson is offline   Reply With Quote
Old 09-16-2004, 01:42 PM   #8
Ruff
Scooby Specialist
 
Member#: 32131
Join Date: Jan 2003
Chapter/Region: NWIC
Location: Oregon City, OR
Vehicle:
2006 Nissan 350Z
Was 01 2.5 RS

Default

Yeah, with borla headers my o2 extender didn't work for me either. Running those borlas on some of our cars, the cel is just going to be there.
Ruff is offline   Reply With Quote
Old 09-16-2004, 02:27 PM   #9
PARANOID56
Scooby Guru
 
Member#: 22035
Join Date: Jul 2002
Chapter/Region: SCIC
Location: San Diego, CA
Vehicle:
2003 Brocoma DCab
71 FJ40, 13 DRZ400SM

Default

yea, i have the borla header, and stromug cat back exhasut, and a cobb intake, and have had no Cels ever. and ia have had them on for months.
Shane
PARANOID56 is offline   Reply With Quote
Old 09-16-2004, 03:22 PM   #10
Subie Gal
GC84Ever
Super Moderator
 
Member#: 301
Join Date: Sep 1999
Chapter/Region: NWIC
Location: WA
Vehicle:
1970 FF-1 & '70 Van
02 WRX/01 RS

Default

i too have CAI and Borla headers.. no CEL

the ONLY time i got that CEL, indeed, my rear 02 sensor was bad.

i'd suspect the sensor iteself at this point.
you may want to inspect it for visible damage (my wiring was fray'd)

good luck
Jamie
www.subiegal.com
Subie Gal is offline   Reply With Quote
Old 09-16-2004, 06:15 PM   #11
Brindor2.5
Scooby Newbie
 
Member#: 40657
Join Date: Jul 2003
Chapter/Region: NESIC
Location: Maine
Vehicle:
2008 Impreza WRX
Spark Silver

Default

So i've gathered that the first thing to try and replace is the O2 sensor before replacing the CAT. Any chance that maybe replacing the sparkplugs with NGK?
Brindor2.5 is offline   Reply With Quote
Old 09-16-2004, 08:40 PM   #12
Tim Sanderson
Scooby Guru
 
Member#: 6486
Join Date: May 2001
Chapter/Region: MWSOC
Location: S.E. wisconsin
Vehicle:
00 Impreza 2.5 RS
Blue Ridge Pearl

Default

I've had the cel since o2 I think. The dealer changed the cat twice and the o2 sensor once. After my warranty was up I just left it. Had the cel ever since. p0420. Maybe I should buy a new rear o2. They are pretty pricey though, is there an alternative? Anybody have a part # for a bosch or something?
Tim Sanderson is offline   Reply With Quote
Old 09-17-2004, 12:32 PM   #13
00RScoupe
Scooby Newbie
 
Member#: 57535
Join Date: Mar 2004
Location: Topeka, KS
Vehicle:
2004 FXT
Maroon

Default

Well in my case the extender didn't eliminate the problem, but made it easier to live with.

Personal Observation:
P0420 pops up more frequently with more highway driving, hence giving credence to the hypothesis that the borla headers cool down too quickly. Driving around town less air gets moved under the car and in the engine bay so the computer is happier. Those who have wrapped their borlas (Subie gal included) seem to do much better than those of us that like our borlas naked. I am pretty close to just wrapping mine. Lots of threads on this over at RS25.com.
00RScoupe is offline   Reply With Quote
Old 09-17-2004, 01:49 PM   #14
rabbitnutz
Scooby Guru
 
Member#: 51940
Join Date: Jan 2004
Chapter/Region: NESIC
Location: boobs?
Default

i'd say change the rear 02 sensor, and if you get the urge, wrap the headers...it's not a bad idea to do it, but probably not nessicery....
rabbitnutz is offline   Reply With Quote
Old 09-17-2004, 03:07 PM   #15
BlkTS02
Scooby Specialist
 
Member#: 50142
Join Date: Dec 2003
Chapter/Region: South East
Location: West TN
Vehicle:
2002 2.5TS
MBP

Default

My headers are jet-hot coated, still gives a CEL with the extension.
BlkTS02 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
No luck with the ladies. FiveDoorSVT Off-Topic 332 06-11-2008 09:43 AM
No luck with Parkades Woody Vancouver Impreza Club Forum -- VIC 15 08-10-2004 12:23 AM
I have no luck with cars. Car damage pics. aod Off-Topic 57 07-03-2004 04:47 AM
no luck in the Dressup/Style Forum, trying my luck here MattDell Mid Atlantic Impreza Club -- MAIC 3 05-16-2002 04:40 PM
Searching boards all day with no luck.... krnbk2 General Forum Archive 12 10-22-2000 08:08 PM


All times are GMT -4. The time now is 10:27 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.