Hey guys I just installed dc headers and greddy evo cat-back in my 97 accord lx. It is so tight. Sounds great and gave me a big noticeable amount of power. I had to customize the catalytic converter a bit to make it work. I cut the flange off on the header side and welded the catalytic converter to the down pipe of the header. While I was doing all of this I figured since I live in NY and emissions laws are not that strict I would gut the converter. Ever since the check engine light has been on. I removed the battery neg numerous times to try and correct it, but it just comes back on. I was reading an old thread and it said that on a 97 Prelude and installation of a Random Technology Cat Back, they were complaining about being too free flowing and causing the O2 sensor(s) to trip the check engine light with the P0420 code. It will pass emissions fine; however, your check engine light will always be on which can eventually cause other problems because the computer will be trying to compensate for the problem.
I think this is the same problem I have.
If anyone can give me any suggestions that would be awesome.
Otherwise I guess the only way around it is to take the whole thing back down cut the weld buy a new converter, modify that without gutting it and reassemble everything. My other option is to somehow disable or trick the secondary O2 sensor on the converter so it wont trip the light. There was a thread about this at Honda- Acura's forum, but it was hard to understand their instructions. Has anyone ever had this problem and know how to bypass the sensor? Also is this ok to do? If i do this will the sensor still work?

 

The only way i can think of tricking your ECU and telling it that everything is fine with the sensor (getting enough air etc...) is by using resistors. You will have to do some more research on this LOL just like that crap they sell on ebay (INCrease your HP) with a dinky resistor.

 

I have a buddy that was running a turbo on a 99 civic Si and he was having O2 sensor codes left and right so he bought these sensor divertors from Jesper ( I think that's the name of it) What they do is trick the O2 Sensor to think it is running right so the ECM will function properly. Two reasons why I won't do that is... Emissions picky techs and if something really is wrong with the engine/exhaust you'll never know.

 

dude... dont bump 2 year old threads.


I hope he found a way out h:

 

The ans. to your problem is " 02 Simulator" from Summit Racing Equipment". At a cost of around $85.00. workd great.

I know you are running the strip and wouldn't think of using it for street!

 

dude... dont bump 8 month old threads.