Megan Header

[20civic00]

i have the megan 4-2-1 header and i put the first o2 sensor in the first bung hole, and the second o2 sensor at the pipe collector(not after the cat.) a mechanic wich just replaced my cat because i broke the racing one said that i'm prolly running rich because the o2 sensors aren't where they need to be. is this true or should i extend the sensors?



heres where the bung holes are:
my car is a 2000 DX
http://i100.photobucket.com/albums/m19/20civic00/DSCN0788.jpg

[custom_junky]

how many o2 you have? i have an ex, and based off that you need to have the primary at the first bung, and the second o2 after the cat...

[20civic00]

i have two o2 sensors. the one before the cat i put in the first o2 bung, the one closest, and the second sensor where the pipes all collect together.

[20civic00]

do i need to move the o2 sensors? am i really running rich because of where i have them?

[20civic00]

so do i just put the 1st sensor in the bung hole at the top of the header, or at the bottom? i think im gonna put the 2nd after the cat tomarrow.

[NS_Y7]

Yep put the first one at the top of the manifold.....the 2nd AFTER the cat...otherwise its useless. If your car is anything like mine the check engine light will come on as my cat is busted and not doing a thing.

[20civic00]

so the 1st one i dont need to put where the pipes all collect, just at the first bung hole, and for sure extend the 2nd one after the cat?

i wont be running rich if i put the 2nd o2 sensor after the cat and thats it?

[93civiccx]

Yep put the first one at the top of the manifold.....the 2nd AFTER the cat...otherwise its useless. If your car is anything like mine the check engine light will come on as my cat is busted and not doing a thing.

Correct. It's an obd-2 car so you HAVE to have one after the cat or it'll run like shit. I think summit racing sells an o2 sensor delete for the after cat sensor, which plugs in like an o2 sensor, but it's fake. It tells the ecu that everything is fine so you can do away with the cat.

[AllmotorRex]

^true

[inh]

i would plug in the first sensor where all the tubes collect in to one so that you get a better reading. that first one up on the header by the head is there for 88-91 EFs because thats where our o2 sensor is

[4Door Life]

i would plug in the first sensor where all the tubes collect in to one so that you get a better reading. that first one up on the header by the head is there for 88-91 EFs because thats where our o2 sensor is

x2
i did this on my civic, seems to get better reading's at the bottom of the header... i made a o2 simulator for the rear as well... runs fine... even passed smog a couple weeks ago...

[turbohappy]

You don't even really need an o2 simulator. Just plug in a working sensor, put the sensor in a plastic bag and zip tie it somewhere. It would be best to just put it on just past the cat like it's supposed to be though :)

[custom_junky]

sorry about the late post...ok, they are all correct, but i agree with turbohappy in putting the second one after the cat...the simulator is not the best way to go, it is there for a reason and is used to help with the afr ratio...

[4Door Life]

sorry about the late post...ok, they are all correct, but i agree with turbohappy in putting the second one after the cat...the simulator is not the best way to go, it is there for a reason and is used to help with the afr ratio...

i used the simulator cause i didnt have a cat for a long time...

[20civic00]

ok i have the o2 sensor passed the cat now. i ran the car for a couple of days and it idles allot smoother. small gain in acceleration if any but i shouldn't be running rich now :)

[custom_junky]

^^bingo!!