Removing The Cat?

[David K.]

I want to remove my cat. I don't need any replies regarding pollution and wether or not I should do this. What I'm curious about is the secondary oxygen sensor, the one downstream of the cat. If I remove my converter the secondary sensor will obviously notice, but when it reports back to the computer will it do anything about it? Or will it just throw up a check engine light? If it's gonna hurt performance by adjusting the A/F ratio I won't do it. Does anyone know?

[MadMax]

Good question. Ive heard 2 answers so far:

1. No, it wont hurt performance. Get a test pipe it is great. Just reset your ecu when the check engine light comes on.

2. Yes, it will hurt performance. The 2nd o2 sensor tells the ecu that the cat isnt working properly. The ecu assumes the cat is cold (startup conditions) and richens the mixture in an attempt to warm everthing up. You need an o2 sim, which is not yet available for our cars.


:confused:

[02blksi]

dont know about the newest obd 3 systems that are in our ep's now BUT, in my old 98 coupe obd 2 i ran a test pipe into 3inch mandrel bent exhaust (turbo setup). I can tell you the car that since i had the car the MIL/CEL was on (haha) I was very familiar with jumping the conector and reading the MIL code to see what triggered it the most comon MIL was the "2ndary oxygen circut low voltage reading" possible cause - bad cat... As far as affecting performance, it had NO AFFECT AT ALL, it merly triggered the MIL and that was that, THE only sensor that will trigger an MIL and affect the engine performance is the PRIMARY o2 which controls the fuel content of the engine, TPS sensor, MAP sensor (DOESNT LIKE BOOOOST:) LOL), Crank angle sensor , and also if a misfire is detected.All of these will send your ecu/car into LIMP dick (:) ) mode so as long as the primary is untouched and the secondary trips the CEL you should be ok, UNLESS obd3 is different. -joe good luck.

[themi6group]

i agree with some of 02blksi, i don't know obd 3 yet but the secondary o2 sends signals for catalyst. you may not gain anything by removing the converter but will probably lose performance and throw a cel which should retard your ignition timing and add fuel. it's not worth it man. if you do so get a o2 simulator http://www.bobblick.com/techref/projects/o2sensor/o2sim/o2sim.html. be our test dummy and let us know how it works out

:p

[Hondatech]

The EP is still OBD-II, just a more advanced (read: more restrictive) version. While the old ones were ok with the second 02 seeing no cat (Just lighting off the CEL and trying to tell you that if you really, really love the trees and squirrels, you should get it fixed), the new ones will putcha into limp mode. This isn't any fault of Hondas, this is a US government regulation. Seems people don't worry if the CEL lights and it still runs ok, but they panic and head for the dealer when the CEL lights and it runs like a dog. A good working 02 simulator is gonna be our best friend if we want to get maximum power outta the K series...

[02SilverSiHB]

just remove the sensor from the cat now and tape it off. Drive around for a while and see what happens.

[SpeedRacer]

yea i think that is what im going to do when i get around to it