Hi there, I have a 1999 civic dx hatchback, non-vtec d16.

I recently bought a dc sports ceramic 4-2-1 header to replace my cracked stock manifold. I got it home and realized it only has one o2 bung at the bottom of the header instead of my old one with 2 bungs (top and bottom).

1.can I just get a second one welded in at the top and be good to go?

and 2. will running 2 sensors with no cat light up a cel or cause issues?


excuse the ignorance, my first import.

 

Are you not running a cat? That's where the second one is on the EX.
Edit. You said no cat. See below post.

 

no cat = cel

 

if you are putting a 421 header on a CX,DX,LX,HX, then you need to use an EX cat converter, and an EX midpipe. and you need O2 extension harnesses

 

Stock manifold on my car has a cat built in right below the exhaust header, then connects to the rest of the exhaust piping.

How can I run an aftermarket header without a cel then? I have a custom exhaust on from the downpipe back.


I dont want to put a stock manifold back on but if I have no choice then...

 

ok ignore my last post, So basically I need to run a cat behine the header and extend my o2 sensors?

 

exactly what i said to do!

4-2-1 header ----- EX cat converter ---- EX midpipe ----- Stock muffler

basically you are putting an entire EX exhaust on your car. except for the muffler. the muffler depends on what body style you have.

use the corresponding muffler (but you already have this, so skip)

hatch
coupe
sedan

 

i know they dont like external links, but its the best writeup i know of


http://www.hondacivicforum.com/forum...version-73237/

 

I have a full exhaust from my stock manifold/cat combo running to a littl magnaflow muffler and tip, so i wont be using an ex cat, would an aftermarket cat work too?

 

yes use whatever you want, but it MUST BE FOR AN EX!

use a magnaflow high flow cat converter

 

ok so last time (sorry in know im new) If i get an high flow cat and weld it in, then put the o2 in my manifold and one after the cat, ill be fine.

Does the high flow have to be and ex cat or can it be a generic magnaflow cat.



thanks.

 

Just make sure you can install an O2 sensor in it. You're making this too hard.

 

ok thanks, appreciate the help!

 

why why why would you want to weld it? everything bolts up if you get the proper parts!

you can use a generic magnaflow cat, but make sure you get an O.E replacement. AKA, BOLT IN.

 

If it's universal you'll need to weld it.

 

huh....I've got a 1998 dx running edelbrock header (both O2 sensors connected), apexi ws2 catback exhaust, no cat-no cel

 

then something is wrong with your car because there should be a catalysis efficiency code

 

must be running obd1 jumper

 

Huh?

 

we were referring to pliskin8's comment about having a 98 dx with no cat, and no CEL

 

But OBD1 anything only needs one sensor.

 

exactly, which is why i said he must be running an obd1 jumper in his 98 to not be having a CEL for no cat.

 

I guess. But he wouldn't need two sensors. Otherwise he should be throwing a CEL unless this is tuned to run otherwise. Makes no sense to me either.

 

no odb1 jumper, legit odb2 passes smog like if it was new

 

You don't necessarily need a catalytic converter. You can run a test pipe (a hollowed out cat) with an o2 fouler.