Do i absolutely need it? Some say no (including a very reputable source) and some people on here say yes...

can i just plug the bung and run without the o2 sensors? i know that i will get the SES light but will anything else happen?

again this is for the o2 sensors that screw into the cat/tp itself... NOT the air/fuel ratio sensor...

oh yeah and the reason i dont want to run the 02 sensors for now is because the retarded design of my helix test pipes position the bung downward so as the non foulers are stacked on it the o2 sensor gets closer and closer to the ground where they can be ripped off during driving (im lowered) and also the water will collect in the bung with the potential to drown the up pointing sensor... it is absolutely beyond me why helix would point the bung down...

 

You don't need the downstream sensors, they are for emissions. If you don't mind the CEL, you'll be fine without those o2 sensors, the upstream ones are the important ones.

 

Well im not sure about the previous comment, I some how pulled a bonehead move and forgot to plug the connector into the test pipes. Gas mileage was greatly affected, took forever on a trip to move. I have since plugged them back in and now have no CEL and the car feels more responsive.

 

thanks thats what i was looking for...

 

They are for emissions, but you don't need them. Yes if you leave the hole uncapped that's an exhaust leak = bad gas mileage. You must cap them! I have had mine off and on for the last 60k miles and it drives the same, I just put them on when I want to try to fix the CEL.

They are meant to make sure your Cats are working... and you don't have Cats anymore... so without non-foulers, and sometimes even with non-foulers, YOU WILL GET A CEL!

 

oh right... im dumb, i assumed djscotty pluged the holes.. of course if he forgot to plug them then yeah those things will happen...

ok so it sounds like it wont affect performance.. thanks!

 

no, the wholes were plugged, i somehow did not get the connector plugged in. There was no exhaust leak at all. Just for example, I drove a 25 one way trip today and the mpg was right at 26mpg, it took me almost 200 miles for it to reach 26mpg with the sensors not plugged and the CEL on. The car is way more responsive than with the CEL on.