Alright so I'm removing the cat from my 97 max, I already bought the straight pipe to put in its place. I've been looking all over the FAQ's and I'm pretty sure that if I want the ECM not to throw a check engine light, I just need to install an 02 simulator to make the computer think the cat is there and working properly. This is all I need to install in place of the oxygen sensor, correct? If anyone reading this has replaced theirs and can recommend a webpage where I should buy my O2 sensor, that would be great. Thanks

 

Find the sparkplug anti-fouler mod and you should be golden.

 

i recently bought and installed my simulator from www.3sx.com(~a month ago)

 

I would definitely try this first and then if necessary do the Sim.....

 

thanks guys. I'll try the spark plug anti fouler method first and if that doesn't work ill buy the O2 simulator. thanks for the link to the website.

 

Alright, well the spark plug anti-foulers I purchased are solid steel and I was not able to drill a large enough hole in one of them. However, I took one of them, filled it with RTV and plugged the 02 sensor hole with it. I just zip tied the 02 sensor to the underbody. So far so good. I drove it for 20 miles today and no check engine light. Can't wait to see how much I can get for this cat .

 

Why not leave the o2 sensor plugged into the exhaust?

Edit: Just saw you have a 97. I've never thrown a CEL for the main cat and I've been running a test pipe for over 2 years.

 

Well I didn't insert it back into the exhaust because I thought the computer would recognize that I don't have a cat and retard my timing, but if what your saying is true I might just reattach in to the exhaust... So you've been using an exhaust without a cat and all 02 sensors in the proper places and you haven't had the CEL illuminate?

 

If anything I'd think it would be more harmful for it to not detect ANY exhaust gases at all. Correct, no cats with all sensors. The only time the CEL lit up was when my primary o2 sensors bit the dust.

 

This is good to know because I just dropped my main cat last night and replaced it with a 240sx test pipe.

 

Won't your 02 sensors detect that your cat isn't filtering your exhaust and have the ECM retard your timing?

 

the o2 sensor that is connected to the cat only monitors whether or not the first two sensors UPSTREAM are working. THOSE affect timing. The downstream just tells your system if they are working or not and does not change timing at all.

 

You both are incorrect. The post cat sensor only monitors catalytic converter efficiency. It will not affect performance pr driveability in any way.