Subaru WRX Forum banner
Cancel

Catless downpipe and o2 sensor issues

6509 Views 12 Replies 6 Participants Last post by  Mikee02wrx, 
M
3
02 wrx
I'm the 3rd owner, and seems the previous owner was an eBay shopper.

The sensor somehow disconnected and melted against the dp. It is not the OEM o2 sensor, I can't find it anywhere and doesn't even look like an o2 sensor. Plus the dp has no markings so I cannot tell what brand it is. The bung is located near the turbo. Wondering if anyone has this setup and what kind if sensor it is.

If no one knows, what's the recommended dp that will pass emisiontest in cali? Many thanks everyone!
Auto part

Auto part Fuel line Brake Vehicle brake Disc brake

Attachments

See less See more
Reply
Save
Like
1 - 13 of 13 Posts
livid_wrx
Buy invidia downpipe, buy oem o2 sensor. Trash what ya have.
Reply
Save
Like
McBill
lol if there was something worse than ebay parts, this would definitely fit the profile. I'm with livid, scrap what you have a replace everything that looks as shotty as this with quality parts.
Reply
Save
Like
N
Front or rear O2? I'm in a similar boat, have a mystery DP I want to replace.
Reply
Save
Like
livid_wrx
Front should be replaced with a quality wideband.

Rear can simply be a oem since it's downstream.
Reply
Save
Like
M
Sounds like a plan. Invidia downpipe and oem sensor. Thanks you guys!!
Reply
Save
Like
M
Wait, so I'll need 2 bungs for the sensors? Wide band and the OEM o2?
Reply
Save
Like
M
On mine it is the rear o2, but strangely located up top next to the turbo instead of by the wheel like others.
Reply
Save
Like
MainFrame
livid_wrx said:
Front should be replaced with a quality wideband.

Rear can simply be a oem since it's downstream.
Click to expand...

The front sensor needs to be OEM.. the ECU needs readings from the front for closed loop fueling corrections, and an aftermarket WBO2 won't give it the right data.


Mikee02wrx said:
If no one knows, what's the recommended dp that will pass emisiontest in cali? Many thanks everyone!
Click to expand...
livid_wrx said:
Buy invidia downpipe
Click to expand...
Mikee02wrx said:
Sounds like a plan. Invidia downpipe and oem sensor. Thanks you guys!!
Click to expand...

To pass emissions you will likely need an OEM downpipe. If they actually do emissions testing where you live then an aftermarket catted downpipe will usually fail for high NOx levels and/or not pass visual inspection.


Mikee02wrx said:
Wait, so I'll need 2 bungs for the sensors? Wide band and the OEM o2?
Click to expand...
Mikee02wrx said:
On mine it is the rear o2, but strangely located up top next to the turbo instead of by the wheel like others.
Click to expand...

Sounds like you have an aftermarket WBO2 sensor already in there. In your year model car the rear O2 sensor is only used for emissions purposes. You can do away with it completely and just run the OEM front O2 sensor with a stage two tune and it will be fine (but might not pass emissions sniffer test).

If you want to custom tune the car then a WBO2 sensor is very useful, and should be placed downstream from the turbo, either in the downpipe, or in the OEM midpipe rear O2 sensor location.
See less See more
Reply
Save
Like
livid_wrx
****, got is backwards... Woops lol.
Reply
Save
Like
XJman
You will fail any emissions test with an aftermarket downpipe. Catted or catless. On occasion someone will find a podunk shop that doesnt care and will just pass the car.

You'll want to find an OEM front O2 sensor, a wideband wouldn't hurt, but provides nothing usable to the ecu, some aftermarket downpipes already have a bung for the sensor. The rear O2 is an emissions device, if it is missing, damaged, or disabled it will instantly fail emissions.

Sent from my SAMSUNG-SM-G935A using Tapatalk
Reply
Save
Like
M
Well my carcurrently has a catless downpipe, which makes me wonder what kind if mess this previous owner left me with. It passed emissions last year without hesitation.

Mods:
Catless downpipe
DC headers
Larger radiator
Catback exhaust
Reply
Save
Like
M
Update

She just needed a good hard beating on the road. Not sure why exactly, possibly be sure it was sitting for 2 full weeks made it throw the codes. She's running now :)
Reply
Save
Like
1 - 13 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Subaru WRX Forum
We invite you to join our Subaru Impreza WRX and STi community to discuss engine mods, builds, detailing, and more.
Full Forum Listing
Explore Our Forums
Engine Modifications Everyday Impreza Talk General Maintenance, Troubleshooting & Accidents. Exterior & Appearance Comparison: WRX vs World
Top