Im getting a service engine light because one of my sensors is reading the fuel ratio may be too rich, i asked around and they said it may be that my cat was replaced with test pipe and the sensor isnt reading it correctly. Do you think it would be possible to trade someone my test pipe for their cat? test pipes are suppose to give better air flow right? but i just want my light to turn off and i def dont want my car to run rich (mpg is bad enough). what should i do about this problem T.T

 

You just need to install non-foulers in the TP bungs before the O2 sensor. $10 fix

 

can you dumb it down for me...
i have no idea what you just said LOL

 

The short answer is that yes, the rear O2 sensors are throwing a check engine light (CEL) due to no cats. This should not make the car run richer than normal nor affect gas mileage at all. The rear O2 sensors are AFTER the cats and only used for emissions purposes. The tune of the car is based off of the front O2 sensors which are located BEFORE the cats, which are not affected by whether or not you have cats or test pipes.

The non-fouler trick is a great cheap simple way to prevent throwing a CEL. It basically spaces the O2 sensor back so the "probe" end is back out of the air stream and gets a smooth signal and doesn't know there are unburnt gases passing by. Google search for "non-fouler trick" and you will find a variety of tutorials from various car forums. Here is the first one I found which has photos that clearly show what you need to do. You will need 2 sets of 18mm spark plug non-foulers (they are sold in pairs, so you will need 4 pcs total).

http://www.honda-tech.com/showthread.php?t=1841240

 

Wow thanks so much for taking your time to explain that to me.
That's is a really good solution, so I should just do that instead of putting a stock cat back right?
Test pipes give better air flow especially if I have intake/ headers/ full exhaust right?

 

Glad to help. YES - test pipes will flow MUCH better than stock cats, or even high flow cats. I would definitely keep the test pipes on to maximize your gains and just do the non-fouler trick.

 

Hi, im looking to buy exhaust for my G. I have top speed headers waiting to be installed. My main reasons for exhaust is for hp gains and if possible backfire. I dont think the headers delete the cats even though they have an input for the sensors on them. I went on customg35.com and found cat-back exhaust $275 ONLY!(3" piping with 4" tips). Only worry is the sound which im trying to get a clip sent to me so i can hear it. If anyone knows how the exhaust lay-out works please post. I want to know if its headers, test pipes, y pipe, and then cat-back exhaust(in that order). I got the looks, time for the power.

 

Well the word catback accounts for everything from the cats back. It goes in this order...

Headers, cats (or test pipes), y-pipe, mid pipe, muffler, tailpipes

The kneebone's connected to the...Y Pipe

 

True but when u c cat-back exhaust systems its usually the midpipe (what looks to be a long pipe) that goes all the way back to the tips. So no y pipe or testpipes included. So lets say i get an rsr gt2 catback (kus thats wat im looking to buy now due to the sound nad straight thru pipe design) with the top speed headers that i already have at home, i will need to get test pipes and a y-pipe in order to complete the wholes catless exhaust system. True or no?

 

Well, I should mention I'm not an expert by any means. I'm still stock, lol

Usually, that would be called a Y-Back, but not all cars have dual exhaust, or two cats, etc. So a catback for other cars wouldn't need a y-pipe. It looks like they make exhaust systems for lots of cars, so maybe that's why it's still called a catback with no y-pipe.

But what you're buying doesn't have a y-pipe, I'm pretty sure you'll need one. Unless your stock y-pipe fits.