what to do with o2 sensor with test pipe

[schultz9008]

here in a few weeks i am getting a full exahust system and i am going to run a test pipe to get rid of the catalac converter. the other thing i am trying to understand is what do i do with the o2 sensors. are they attached to the cat. and if so what do i do with them. someone please help me out. thanks

 

[LiquidX]

Well, you are going to have a CEL come on if you just remove the rear o2 sensor. The sensor is there to take readings from the cat to make sure it's doing it's job and relays it's operation to the ecu to fine tune gas injection to promote optimun operation. You can get rid of the o2 by making a "fake sensor" (can't remember the actual name but it's on the forum) and it will get rid of the CEL.

Personally, I would keep the cat as it's giving you needed back pressure for your engine.

 

[VelocitàPaola]

Well, you are going to have a CEL come on if you just remove the rear o2 sensor. The sensor is there to take readings from the cat to make sure it's doing it's job and relays it's operation to the ecu to fine tune gas injection to promote optimun operation. You can get rid of the o2 by making a "fake sensor" (can't remember the actual name but it's on the forum) and it will get rid of the CEL.

Yep, they're called oxygen sensor simulators.

Personally, I would keep the cat as it's giving you needed back pressure for your engine.

That is false.

 

[my dreamt dsm]

I thought that there was ways to manipulate the o2 sensor. Like wrapping it up in aluminum foil or something. I read it on here somewhere but Im having a hard time finding the link! Good luck grass hopper!

 

[Fotowntalon]

here in a few weeks i am getting a full exahust system and i am going to run a test pipe to get rid of the catalac converter. the other thing i am trying to understand is what do i do with the o2 sensors. are they attached to the cat. and if so what do i do with them. someone please help me out. thanks

The 02 sensors are before and after the cat, not on it, so you should be good. If it is a half decent exhasut system, it should have the holes in relativly the same place as the stock system. As for the 02 after the cat, you may get a CEL for your cat beeing ineffective(obviously it wont be effective without it beeing there, althoguh it has not happened to me yet) there are ways to bypass this though, which i beleive is what everyone else is talking about.

 

[Flipboi89]

You will get a cell probably for after the cat. I'm catless and my cel threw off when it was messed up.

 

[RoninEclipse2G]

There are 2 ways to fool a rear O2 sensor. The best way is to use an O2 simulator. The other way is to put a spark plug anti-fouler on the end of the O2.

 

[RiGs2G]

UGH, I tell everyone about this. I pulled the O2 sensor out of the exhaust, and plugged the hole. Then I used some bailing wire and safety wired the O2 sensor to the side of the exhaust pipe. I have done this since I bought the car in 03 and have NEVER thrown a CEL. My guess is the computer thinks the cat is doing a really good job and keeping the air clean. haha. It works, believe me and dont buy a thing. If you have an old O2 sensor then put that in the hole in the exhaust.

 

[VelocitàPaola]

UGH, I tell everyone about this. I pulled the O2 sensor out of the exhaust, and plugged the hole. Then I used some bailing wire and safety wired the O2 sensor to the side of the exhaust pipe. I have done this since I bought the car in 03 and have NEVER thrown a CEL. My guess is the computer thinks the cat is doing a really good job and keeping the air clean. haha. It works, believe me and dont buy a thing. If you have an old O2 sensor then put that in the hole in the exhaust.

The 4G63 PCM is different than the 420A PCM; it's far less likely to throw a CEL for a malfunctioning cat/rear O2 sensor than the 420A PCM.

 

[schultz9008]

now i have some people telling mee that it is bad to straight pipe and it is good to straight pipe. i would like an honest opinion because i dont know why you would honestly need a cat, you would think it would give you more airflow creating more power or w/e but someone let me know if im wrong or something thanks

 

[Diamondrev]

cat is only for emissions.. more flow, more power period.

 

[Fotowntalon]

only reason for a cat is if u live in an area with that is strict on either emisions or noise or both, straight pipe will be louder.

 

[RiGs2G]

The 4G63 PCM is different than the 420A PCM; it's far less likely to throw a CEL for a malfunctioning cat/rear O2 sensor than the 420A PCM.

That I didnt know! You would think the 4G63 would be more senitive because its a higher performance style engine.

 

[VelocitàPaola]

That I didnt know! You would think the 4G63 would be more senitive because its a higher performance style engine.

Sure? It's also a lot older.

 

[2gGSXEclipse]

Every naturally aspirated 4 stroke gasoline or methanol engine will run it's best with no back pressure. Any automotive engineer or racing engine builder will confirm that.

The problem is, virtually all carburetors and fuel injection systems were designed for engines that are muffled and have some back pressure. The result is many times when back pressure is reduced or eliminated the fuel curve is disturbed and the engines often loose low end torque because of the mismatched lean fuel curve. A simple jet change many times wont correct this. It requires a completely new fuel curve that is beyond most people's capability. This results in many people believing some back pressure is necessary,

Best thing is take two spark defoulers....drill one out with i believe a 1/4" bit and screw both together..then screw in the spark plug. This acting as a spacer for the o2. The ONLY thing the rear o2 does is make sure there is a change in voltage which is saying there is a cat there. The front one is what the ECU referes to as far as A/F ratios.