**Everything you need to know about eBay headers**

These questions have been answered many times,and there are different approaches to the fixes. You MUST run with at least the two PRE CAT sensors installed in the proper exhaust banks or you will be taking risks ranging from poor engine performance and economy up to total engine failure from overly lean or rich conditions. Also,cutting holes in a 10,000$ car to fit 99$ headers is really as dumb as it sounds. The proper repair it to cut off and relocate the o2 bungs to a proper location. As far as sims go for the post cat, I reccomend you search those options when you get to it as there are many available fixes.

sent from my ATARI sc1224

Originally Posted by daniel_f.

Why don´t you just mount underfloor cats? Just weld in 2 bungs for the post-cat sensor and you´re ready.

If somebody sold that, I'd buy it.

To fabricate it would cost me too much money. And in 2014, the emissions test here will be OBD2 only, so all I'd need to have is a couple of O2 sims.

I installed ebay headers. $80. Looks nice, sounds nice. Im happy.

Originally Posted by E46tknv

I installed ebay headers. $80. Looks nice, sounds nice. Im happy.

Can you link which ones? Fit nice?

Doesnt matter honestly. I dont have a link. All i clicked was "lowest price+shipping" and just picked one. I didnt do the install. Looks like it fit fine but my motor was out when it was being done. The piping at the end of the headers was smaller then the rest of the exhaust so you need to get it welded.

Originally Posted by ac_2007

If somebody sold that, I'd buy it.

To fabricate it would cost me too much money. And in 2014, the emissions test here will be OBD2 only, so all I'd need to have is a couple of O2 sims.

Do you have M or non M? Vivid racing sells racing dynamics and milltek sport cats,also you can pm Donnavin (I think is his screen name) and he can get you oem euro cats. There are many options available.

sent from my ATARI sc1224

Originally Posted by HiHoBrian

Do you have M or non M? Vivid racing sells racing dynamics and milltek sport cats,also you can pm Donnavin (I think is his screen name) and he can get you oem euro cats. There are many options available.

sent from my ATARI sc1224

Non-m

But now I'm thinking of adding cats to the OE catback, and just swapping with my magnaflow when needed. Much easier than a header job.

Originally Posted by HiHoBrian

These questions have been answered many times,and there are different approaches to the fixes. You MUST run with at least the two PRE CAT sensors installed in the proper exhaust banks or you will be taking risks ranging from poor engine performance and economy up to total engine failure from overly lean or rich conditions. Also,cutting holes in a 10,000$ car to fit 99$ headers is really as dumb as it sounds. The proper repair it to cut off and relocate the o2 bungs to a proper location. As far as sims go for the post cat, I reccomend you search those options when you get to it as there are many available fixes.

sent from my ATARI sc1224

What exactly do the post sensors do for the car performance wise? No obviously i wont be cutting any holes in my floor board it was a joke my friend.

Thank god it was a joke. The rear sensors are mainly used for monitoring cat efficiency,but some information has shown a check and balance signal that is measured between pre and post for fine tuning of fuel trim for emissions purposes. It doesn't appear to be significant because may people run without them and use sims,lc1's,a eu2 tune,an aftermarket tune,or a simple resistor and cap mod that works.

sent from my ATARI sc1224

Yea i just been hearing a lot of different stuff like others saying that the post o2 sensors dont really and ignore them to loosing performance on the car not having them on so i have no idea what to believe. Any idea what the pre cat sensors do?

Originally Posted by lrz14

Yea i just been hearing a lot of different stuff like others saying that the post o2 sensors dont really and ignore them to loosing performance on the car not having them on so i have no idea what to believe. Any idea what the pre cat sensors do?

Everything. Air/fuel mixture.

Your car won't run without them.

http://www.mr2.com/TEXT/O2_Sensor.html
Here you go.

sent from my ATARI sc1224

Since we are on the subject of O2 sensors, I recently wired in my O2 sim in the last month. It has been wired in correctly, however the SES light is still on. Ran faults, and the sims have indeed eliminated the cat deficiency codes, but now I am running codes for post O2 sensor heater circuit malfunction.

Has anyone ran into this problem wiring in their o2 sims? Does anyone maybe have a solution to simulate the heater circuit in a similar fashion to how the post sensors are simulated to complete the circuit and turn off the SES light?

Anyone know the resistance on the heater wires?

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I had my guy make me o2 sims and post o2, cats, and heater codes were gone. Read sig.

Good chance the wire was poorly soldered and it disconnected.

And the ses light wont just turn off. You need to clear the codes after you install the sim.

Originally Posted by threetwentyfizzle

Since we are on the subject of O2 sensors, I recently wired in my O2 sim in the last month. It has been wired in correctly, however the SES light is still on. Ran faults, and the sims have indeed eliminated the cat deficiency codes, but now I am running codes for post O2 sensor heater circuit malfunction.

Has anyone ran into this problem wiring in their o2 sims? Does anyone maybe have a solution to simulate the heater circuit in a similar fashion to how the post sensors are simulated to complete the circuit and turn off the SES light?

Anyone know the resistance on the heater wires?

Sent from my HTC One XL using Bimmer App

All i can think of to help you out bro is the info provided here in this thread. http://forum.e46fanatics.com/showthr...lug+non-fouler.

Can anyone tell me what they did to make stock o2 sensors work on headers from trader nas? Or if they work at all. Do they fit into the holes without leaks. I dont know much about headers but im looking to purchase a set, but dont want to run into any problems. Sorry for not searching I need a quick answer...and thanks in advance.

Originally Posted by HiHoBrian

Thank god it was a joke. The rear sensors are mainly used for monitoring cat efficiency,but some information has shown a check and balance signal that is measured between pre and post for fine tuning of fuel trim for emissions purposes. It doesn't appear to be significant because may people run without them and use sims,lc1's,a eu2 tune,an aftermarket tune,or a simple resistor and cap mod that works.

sent from my ATARI sc1224

I also wanted to do the spark plug non-fouler mod but woudnt i be fine with the amount of space i have created with the extensions in order to trick the computer? Idk if im anywhere being right on this. Also do you know if my check engine light will go away as soon as plug in the post o2 sensors or do i need all of them to clear the check engine light or should i clear the code some how?

Originally Posted by lrz14

I also wanted to do the spark plug non-fouler mod but woudnt i be fine with the amount of space i have created with the extensions in order to trick the computer? Idk if im anywhere being right on this. Also do you know if my check engine light will go away as soon as plug in the post o2 sensors or do i need all of them to clear the check engine light or should i clear the code some how?

Read the past few pages of this thread. The spark plugs defouler mod has already been debunked.

It DOESN'T work.

O2 sim is the only way to get rid of ses light.

Originally Posted by ac_2007

Read the past few pages of this thread. The spark plugs defouler mod has already been debunked.

It DOESN'T work.

I don't know if BMW has tighter parameters but I do know from personal experience that the non fouler trick worked perfectly for me on a 2001 Gmc Jimmy. It has been installed for almost a year and the light never came back on and the cat was completely gutted out.