GSRSRT

Wasup guys my question is how many foulers i need to put when installing the OBX headers should i put one on each O2 sensor or what?

timgs300

iTrader: (22)

Don't know what a fouler is, but I'm guessing since you are effectively removing the cat, there are two before the cat (that you are removing) and so you would leave those alone - they control fuel mixture. The two after the cat would be the ones that would give you trouble since they are used to detect the correct function of the cat. Hope this helps.

99 GS3

iTrader: (14)

They are only used for sensors After the Cat! Don't put them on the sensors before the cats.

They are used to pull the probe out of the direct exhaust stream which makes it less sensitive so the sensor thinks the cat is still working. If you put them on the pre-cat sensors your air/fuel mixture could get messed up.

GSRSRT

ok so i want to know where do i put them according to your answers i need to put them after the cats because my CEL is on

Alexus_300

iTrader: (4)

Depending on which O2 sensor simulator you get, it is wired in differently. I have one from toyomoto and it is wired into the O2 sensor that is on the Y-pipe and works perfectly for the last three years. I also have another one laying around if you want it.

GSRSRT

how those this hook up i thought all u need is 1 or 2 foulers for the O2 sensors and thats it

99 GS3

iTrader: (14)

^^^ Alexus is talking about O2 simulators, that's a completely different solution. That is a circuit board that you wire to the O2 electrical feed and you can remove the O2 sensor all together.

You mention needing one or two together when using de-foulers. I think you are refering to using Spark Plug Defoulers found at most autoparts stores, those are sold as straight/inline spacers and are very shallow requiring to screw 2 together to get the height needed to get the probe out of the exhaust flow.




The b-pipe/mid-pipe sensor is not going to work using the straight de-foulers, there is not enough room between the body and the pipe for the extra height. You have to use a 90 degree elbow O2 de-fouler to fit in that location.

(not a GS in pic)


As far as the CEL goes, you should be getting a P0420 catalyst effeciency code. Yes it will eliminate that code. Have you have the CEL code pulled yet? Is that the only code your getting?

GSRSRT

(99 GS3) Yes that is the only code im getting as there is nothing wrong with the engine and i never had a CEL before i installed the OBX headers so my question is where to install the De-Foulers and yes i know u will have to put two, one on top of the other and use a hath bit to drill a hole so the O2 can fit but i want to know witch O2 sensor will need the de-fouler

smuv gs3

iTrader: (1)

Put them on bank 1 sensor 2 and bank 2 sensor 2 and reset your ecu and you should be fine

99 GS3

iTrader: (14)

What I'm trying to say is that straight spark plug df's will Not work on the Second Sensor (the one under the car, below the passenger seat). You have to use a 90 degree one for that location.

There is just not enough room between the floor pan the pipe to extend the sensor out 2 inches. I had to get a 90 degree to fit under mine.

Not sure about any clearance issues on the other o2 hole that will be on the obx header, but the defouler will go in the lower hole on the pipe with two holes.

GSRSRT

OK so the 3 holes Before the Y-pipe stays with the stock sensors and right after that i put a DF and my CEL will go away and with a 90 degree angle like u said

99 GS3

iTrader: (14)

You need to fix both sensors after the cats. One in the y/b/merge/mid-pipe (whatever one wants to call it) under the car and the lower one in the right hand pipe in the pic. See how on the oem manifold that location of the lower sensor is after that cat?

TofuMaster

iTrader: (4)

hey, so if i want to install obx headers and keep my stock ypipe, i need 1 defouler for the header cat and then 1 o2 simulator?

GSRSRT

Based on what everybody said on here i think you just need the 1 de-fouler after the cats or if you don't want to use that you can yous a simulator that's another option

VVISPER

Any one know where to get the 90 degree elbows I need