Test Pipe and CEL Questions, O2 SPacers

[muffinman92]

Hello,

I am interested in getting a set of test pipes for my car and had a few questions that seem to have unclear answers. I will not be tuning the car as I do not want to mess with the software. I would like my mod to be reversible if needed so I do not want the ECU touched. I was wondering how fast does the CEL appear once cleared? Every 100? 200? 1000 miles?


I would also like to know if anyone has been able to prolong this period by having a sort of O2 spacer/defouler added. I know some people have said it does not work to permanently fix the CEL, but I am simply trying to extend the time between clearing CEL's if possible. Would the spacer be added to the second bung of the test pipe or somewhere on the midpipe?

Any input helps.

[NTAC]

CEL popped pretty quick for me. <50 miles I'd guess. Installed BPM tune soon after.

[Cbozz]

Originally Posted by muffinman92

Hello,

I am interested in getting a set of test pipes for my car and had a few questions that seem to have unclear answers. I will not be tuning the car as I do not want to mess with the software. I would like my mod to be reversible if needed so I do not want the ECU touched. I was wondering how fast does the CEL appear once cleared? Every 100? 200? 1000 miles?


I would also like to know if anyone has been able to prolong this period by having a sort of O2 spacer/defouler added. I know some people have said it does not work to permanently fix the CEL, but I am simply trying to extend the time between clearing CEL's if possible. Would the spacer be added to the second bung of the test pipe or somewhere on the midpipe?

Any input helps.

i think macht schnell and fabspeed sell spacers with mini cats in them so you never throw a cel...

or you can get a cheaper alternative https://www.amazon.com/Minicat-Senso.../dp/B00CBKEC06

[OneSickM]

I have been searching for an answer the last 5 days and all I got is it doesn't work and ECU will detect that you had CAT delete and would trigger CEL sooner or later.

[Redd]

A remap is reversible.

[deansbimmer]

Catalysts are checked by the DME every drive cycle. You WILL get a CEL...Spacers don't work. The sensor will still pick up the exhaust flow.

Just get a proper tune. It installs in minutes and can be reverted in minutes...

[BigRussia]

Im running a completely catless and resonator less IPE F1 xpipe for over a month now and I've yet to have a CEL. My car is completely stock besides the exhaust (so no tune) unless PO coded out the cat CEL already somehow but they never changed or messed with the cats so I dont know why they would.

[pbonsalb]

If a catless E9xM3 is not throwing emissions CEL, there is an explanation. Such as it has been tuned. Notice people selling x pipes because they are getting rid of the car and selling it with the stock one?

[Kwike92M3]

Check engine light WILL set. Period.
The entire purpose of the after cat (referred to as post cat or sensor 2) is to read the emissions after being processed through the catalytic converter. If there is no drop in voltage seen by the 2nd sensor in reference to the 1st sensor in the exhaust stream, then the DME will flag a pending code, then a present code, which will produce a check engine light.

Using an O2 simulator is not usually a viable option for BMW owners, as it has very mixed results. Same for spacing the O2 sensor away from the exhaust stream.

The only way to eliminate check engine lights from cats being removed is to remove the test from the DME by tuning it out. This will still allow the vehicle to be inspected in most states as the software simply produces a "not applicable" or "not ready" result for the DME readiness status. If you are going to sell the car, the factory software just has to be flashed back into the DME. This does not damage the vehicle, and is not detectable by any scan tools.

As far as engine safety and performance: nothing is changed. The ONLY job of a downstream O2 sensor is to monitor the catalyst. They will not alter or affect the A/F mixture like an upstream "02 sensor" (read: A/F sensor). You still have full functionality of the DME's ability to detect other sensor malfunctions, as well as the use of safety protocol.

Unfortunately, there is no 100% quick AND easy fix for this. Have the car tuned, or simply use a cat back system of your choice and retain the factory catalysts.

[pbonsalb]

I tried the vibrant 02 spacers/reducers and they did not work. I did not turn them towards the engine, but I did try all 3 reducer fittings to limit the amount of air to the sensor.

[OneSickM]

Originally Posted by pbonsalb

I tried the vibrant 02 spacers/reducers and they did not work. I did not turn them towards the engine, but I did try all 3 reducer fittings to limit the amount of air to the sensor.

Why did the person above you delete the comment ? I was going to try his solution. Did his CEL came after he posted the comment? Lol

[pbonsalb]

I don't know, but you can try what he did pretty cheaply with some amazon or ebay 90 degree extenders and something to restrict flow to the sensor. Maybe it will work for some people.

[BPMSport]

Extenders aren't going to work on catless cars. You can get away with them in some cases with 200HFC setups.

Proper tune is best avenue.

[Solo_M_Tech]

You will need a tune. 100%. I also don't understand. You want the mods to be reversible. So you are ok with installing test pipes, which is cutting and clamping ( can't be reversed without welding the OE cat's back on which makes it obvious it's been fucked with) but you are not ok with flashing a tune ( which isn't a physical modification and can be reversed in minutes with zero physical evidence). The logic doesn't make sense. If you want Test Pipes, you will need a tune. That or live with the annoying SES light all the time.

[deansbimmer]

It is 100% false that you need a tune in order to make a CEL go away. Unless any of you have tried every method please don't re-post what you've read from other forums. There is a way to do disable the cel.

There are posters here (and myself) who are professionals and have been doing this for a long time and fix these problems every day, who have forgotten more scenarios than most owners see in their lifetime of tinkering on their own cars. So please forego the insult of calling wisdom from the modern automotive technology pool 100% false. If it were so easy to fool an emissions system 100% of the time, then the entire automotive industry would be different than what it is. Glad it works for you, but it's not the end-all solution for every application that you make it out to be.

Most states will allow at least 1 'Not Ready' monitor to still pass inspection (CEL tune). The rest of the states that require all monitors to be in "Ready" state are also the states who will perform a visual inspection. Those states will immediately return a fail status for either missing cats or a "modified emissions system" due to a sensor spacer.

[urabus040]

Originally Posted by Cbozz

i think macht schnell and fabspeed sell spacers with mini cats in them so you never throw a cel...

or you can get a cheaper alternative https://www.amazon.com/Minicat-Senso.../dp/B00CBKEC06

I've bought the fab speed mini cat and it doesn't work, I have a x6 with a vrsf
Down pipe, spent 225 and got CEL. In theory you'd want the o2 sensor to see some sort of
Flow for it to measure, but this that particular mini cat it's to far away from the stream to read anything, if there was some sort of port or outlet to let gases get to the sensor it prob would work but its basically a bottle with a cat substrate on a 90 elbow and gases just cant get to it. My next step it the 7 dollar fix of the defouler, to see what happens. Dont get me wrong the fabspeed really is a quality part it's welded nice and heavy but its form just doesnt fit the function. Save your money on this one.