Do I need my O2 Sensor?

automatik · 12-02-2006, 05:15 PM

I need some help!! I have an 04 STi and I recently added an HKS downpipe to the car. When it was getting installed, the shop put an O2 sensor on, apparenty to keep my from throwing check engine lights.

When I got my car pro-tuned the other day, the tuner saw it and didn't even know what it was so he took it off (neither him nor any of the others there who have modified STi's before seemed to think it was necessary). I have not noticed any changes or thrown any check engine lights since it was out.

Anyways, since I had not seen the part before it was installed I did not know what it was...so I took it back to the original shop to ask. They informed me that it was the O2 sensor they had put on and that it was essential to have this product in. So I am now confused...does anyone know what is going on with this? Or have any of you had this downpipe with or without sensors and could give me some advice? I really trust my tuner but I am worried I might be missing something here so any thoughts would be great. Thanks for the help.

jarvis210 · 12-02-2006, 05:19 PM

Well o2 sensor is a very important sensor. Not only does it help control emissions but it is a way for the computer on your car to know what kind of air fuel mixture you have. Also the o2 sensor is a ideal sensor that relays information back to the ecu during worn up. If it was my car i would have the o2 sensor put back on.

LogicalXtremes · 12-04-2006, 07:05 PM

Boostpimp · 12-04-2006, 07:09 PM

They were probably reading your AFR's and forgot that they left their sensor in the bung. I wouldn't worry about it.

**WolfPlayer** · 12-05-2006, 12:48 PM

Your car is suppose to have 2 Oxygen sensors. One is located in the passenger side exhaust manifold (which can be reached via an access panel in the passenger side front wheel well). The other O2 sensor in located in the midpipe. You should still use this O2 sensor even with an aftermarket TBE.

Do NOT remove your rear O2 sensor

t

12-02-2006, 05:15 PM	#1
automatik Amateur STI Driver Car: 04 Subaru WRX STi RV Fav Mod: Soft Floor Mats Location: CO Posts: 30 IWSTI Addict since: Nov 2006 Trader Rating: (0)	Do I need my O2 Sensor? I need some help!! I have an 04 STi and I recently added an HKS downpipe to the car. When it was getting installed, the shop put an O2 sensor on, apparenty to keep my from throwing check engine lights. When I got my car pro-tuned the other day, the tuner saw it and didn't even know what it was so he took it off (neither him nor any of the others there who have modified STi's before seemed to think it was necessary). I have not noticed any changes or thrown any check engine lights since it was out. Anyways, since I had not seen the part before it was installed I did not know what it was...so I took it back to the original shop to ask. They informed me that it was the O2 sensor they had put on and that it was essential to have this product in. So I am now confused...does anyone know what is going on with this? Or have any of you had this downpipe with or without sensors and could give me some advice? I really trust my tuner but I am worried I might be missing something here so any thoughts would be great. Thanks for the help. This ad is not endorsed by this member. Please register or login to hide this ad.

12-05-2006, 12:48 PM	#5
WolfPlayer Moderator & ECU Tech Car: 05 CGM STI Fav Mod: mo boostaz Location: Fredneck, MD Posts: 3,716 IWSTI Addict since: Jun 2004 Trader Rating: (6)	Your car is suppose to have 2 Oxygen sensors. One is located in the passenger side exhaust manifold (which can be reached via an access panel in the passenger side front wheel well). The other O2 sensor in located in the midpipe. You should still use this O2 sensor even with an aftermarket TBE. Do NOT remove your rear O2 sensor t This ad is not endorsed by this member. Please register or login to hide this ad.

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12-02-2006, 05:19 PM	#2
jarvis210 Senior STI Driver Car: 04 SUBARU WRX sti Fav Mod: JDM FOGS Posts: 378 IWSTI Addict since: May 2006 Trader Rating: (1)	Well o2 sensor is a very important sensor. Not only does it help control emissions but it is a way for the computer on your car to know what kind of air fuel mixture you have. Also the o2 sensor is a ideal sensor that relays information back to the ecu during worn up. If it was my car i would have the o2 sensor put back on.

12-04-2006, 07:05 PM	#3
LogicalXtremes Professional STI Racer Car: 05 CGM STI Fav Mod: protune-Agile 322.2whp 370.3 Location: Frederick, MD Posts: 661 IWSTI Addict since: Aug 2006 Trader Rating: (3)

12-04-2006, 07:09 PM	#4
Boostpimp Grassroots STI Racer Car: 04 WRB/G STi Fav Mod: Sz49 + Meth Location: South Carolina Posts: 536 IWSTI Addict since: Jun 2004 Trader Rating: (2)	They were probably reading your AFR's and forgot that they left their sensor in the bung. I wouldn't worry about it.