Hey guys
I think this is my first thread..
THE_TECH..I have done a search numerous times, with numerous different key words and phrases..

I am putting on a Greddy EVO 2 and Helix Testpipes
Now I know I need "no fowlers", but I was wondering if I don't put them on what happens
I know 5-6 guys with Twin Turbos who don't have them..

They commented that they ran fine before the Turbos where put on with the Test Pipes and Exhausts.

I just want to make sure I am not going to hurt my car if I don't "no-fowler" my testpipes.
If I just have a light on in my dash, I can live with that

Thanks as always for you help guys
-AJ

 

I Think You Just Get A Annoying Cel Light

 

It defiantly not going to hurt anything. But if you can stand the CEL light, then you'll be ok. But say something else happens with other parts of the motor. You wont be able to know something else is wrong. Non foulers are cheap to do. Just something to think about.

 

It's "fouler" so perhaps that's why your search did not return pages you were looking for. And you'll just get a CEL light, so since you can live with it, you should be fine.

 

We often toss around terms like non-fouler without explanation, and it does members a disservice. On board diagnostics compares the pre-catalytic converter gases (sensor in the header) to the post-catalytic converter gases (sensor at the end of the catalytic converter). If the gases exceed specific limitations, you get a CEL ON showing that something is wrong. The non-fouler in the test pipe is to move the sensor OUT of the gas steam, and trick the diagnostics.

Will everything be OK with the CEL ON? Maybe. One, with the CEL ON, other codes may be hidden. Two, the diagnostics also has the ability to shut down the motor (limp mode). Why take the chance. Go the extra mile, and install non-foulers.

 

I installed the double non-foulers on my test pipes, and I am still throwing a code. Has anyone else had this happen? I reset my computer, and im good for about a few days or so, but if im stuck in traffic, or let it idle hot too long, the light comes on. I have not gotten a chance to check what the code is with a diagnostic tool yet, as I have assumed that its related to my test pipes. my gauges are reading that everything is nice and happy, and it;s running great. I guess I need to swing over to the parts store and have them read my code. so yeah... anyone else?

 

could it kill your O2 sensor?

 

I've seen several threads where non-foulers did not do the trick. I guess just reset it everytime it comes on or get 02 simulators?

 

Thank you everyone for responding
David V as always excellent explanation.
The limp mode scares me....

I will have to see how the car reacts...
If it starts acting up I will get the no foulers..
The car only drives 4.6 miles a day so I should be ok....

now would it be in my best interest to go to autozone every once and a while and see if any other codes are being thrown?
Just a thought, there is one right down the street from me.

 

+1 on just getting the non-foulers b/c it's cheap, easy, and with the SES light on - it could mask other possible problems w/ the engine

I don't think your car will go into limp mode over this issue...the reason the SES light comes on is that you ECU has compared the header O2 to the post-Cat O2 sensor and shows that the Cats aren't doing their job correctly; that's not a reason to go into limp mode b/c the engine is still wokring properly....but, I can't garuentee that that's what Nissan engineers did.

-Peter

 

OK,
I will get the no foulers.
I looked and I thought there was a Sticky with the directions and everything
I searched again and could not find who sells them
I know his name on here starts with a Z...

Maybe I just suck at searching....

 

PM Zexy. I got my non-foulers for $19 shipped in like four days.

 

+1 for non-foulers from Zexy. I just got my set from him too. Nice choice on the exhaust. Put up some sound clips when youre all done.

 

Thank you everyone for your help and advise
It is much appreciated

Transformer-I will post them up once I have it done...
I am thinking of getting DC Headers, and a NX system soon as well...
YEAH Tax checks!!!

 

All the non-foulers do is restrict the amount of exhaust gases that can get to the post-cat sensors. This will trick the post-cat sensors into thinking there is less oxygen than the pre-cat sensors.

So basically it thinks there's a catalytic converter there which is reacting the oxygen with unburned hydrocarbons etc. But in reality, all you're doing is tricking a sensor.

 

I have been lucky so far with mine. My testpipes have the 02 relocates on them and i have not had a cel yet. I thought that the more airflow would trick the 02 sensors but they go in just enough so that they are not getting loads and loads of air. I have only had them a week so i will see how long the cel satys off.