header question...

X

xXx Mazda xXx

Member

:

2008 Mazda3 2.0

• Jul 23, 2008

• #1

What's up guys? Ok I have a question...I recently installed headers to my 08 mazda 3 I touring...it has a 3 way catalyst and on the stock exhaust manifold when I removed it the little cat came out with it and now when I clear the code (po421) after certain amount of miles it comes back on...same code...has anyone figured a way to fix this problem?

 

T

tsunami

Member

Contributor

:

mazda3 5 door

• Jul 23, 2008

• #2

what kind of header? 3 way catalyst? uh? what is code 0421? i am to lazy to look it up

 

X

xXx Mazda xXx

Member

:

2008 Mazda3 2.0

• Jul 27, 2008

• #3

its an F2 header...code o421 = warm up catalyst system efficiency below threshold

 

T

tsunami

Member

Contributor

:

mazda3 5 door

• Jul 28, 2008

• #4

thats probably your second 02 sensor not getting up to temp fast enough do you have it spaced out of the exhaust stream? if so how are you doing that? some guys who use both non foulers if thats your method have gone back to just 1 non fouler due to that problem.

 

X

xXx Mazda xXx

Member

:

2008 Mazda3 2.0

• Jul 28, 2008

• #5

what do you mean by if i have it spaced out of the exhaust stream? i have no non foulers just toke stock o2 senors and put them straight on the the new headers....

 

T

tsunami

Member

Contributor

:

mazda3 5 door

• Jul 28, 2008

• #6

ah ok not sure why you are a catalyst temp error but you need to space out of the exhaust stream the second 02 sensor don't touch the first one. the error should say something like bank one 2 sensor or something like that? its purpose is to tell the car that the cat is working properly by telling it what the mixture is post cat. by spacing it out of the stream slightly you are able to fool it into thinking its seeing what it should. hope that helps... let me know if i can help anymore or if this doesnt' take care of it i have had a lot of work getting rid of my own and others O2 cels due to header installs.

 

X

xXx Mazda xXx

Member

:

2008 Mazda3 2.0

• Jul 28, 2008

• #7

oh ok...but when you say i need to space out the exhaust stream on the 2nd o2, what exactly do i need to do? buy one of those fouled plugs?