O2 Sensor Fix

[deni2316]

Hey guys, so I just purchased a 2014 BMW M6 gran coupe which has been a dream car of mine for years.

It had the check engine light on so I took it over to the local BMW to get it checked out.

They re-plugged a cord that was apparently causing misfires and the car drives like a dream now. Granted they charged me $420 for 2 hours of labor for 1 hour it took them to replug a switch lol.

So after I went to pick it up the check engine light was still on anyway and they told me to come back today to get it diagnosed again.

Then they told me the O2 sensor bank 2 needed to actually be replaced after all and wanted to charge me $400 for a $120 part and $400 for 2 hours of labor for a 15m job lol.

So I picked up my car and ordered the O2 sensor to have my father (mechanic of 20 years) replace it real quick.

Now, the car is on a stock tune, but it has a resonator delete as well as aftermarket akrapovic exhaust tips welded on. What I'm trying to do is see if it's also got catless downpipes on which would explain the issue I'm having with the O2 sensor and would be easily fixed with a tune.

So basically what I'm asking, is there any way for me (not car savy) to figure out if the car indeed has catless downpipes on? I have a video from underneath the car but I'm not exactly sure what it would look like stock to compare to.

Either way after the O2 sensor (precats) is replaced, I will be seeing if a tune gets rid of my issue of it's still same problem. This would be best case scenario as it would save me the cost of doing the downpipes myself haha.

Sorry for the long post and thanks for any help you guys can provide.

Glad to be part of the family.

[TinCanSailor]

Congrats on the M6 and welcome aboard; I see you are in 813 Bay. Rennen and Midnite tuning are good shops if you want to get deeper than what you father wants to get into.

Remove the plastic engine cover and look at the area to the rear of the engine and firewall. You'll see two pipes running down the back center as this is a Hot V design so tings are a little upside down from the traditionally v8's. Take a couple of pictures and uploaded them.

If the cable was off there is a chance the prev owner had downpipes on it and removed them before selling it.

[arucano]

IF you have a cat-less down pipe, you will need some type of "TUNE" to ignore the downstream (after cat) O2 sensor since that is used to check the cat efficiency. If there is no cat or bad cat, it will throw a check engine light with a cat efficiency code with standard software.

[deni2316]

I'll grab a picture of that tomorrow thank you.

I'm hoping this O2 sensor is the culprit since that's what BMW had said and they showed me a cut in the cable from the O2 sensor.

I don't think these are downpipes tho based on the sound and no smell.

To note at times when I open it up to yellow/redline I get the drivetrain fault code pop up and limited performance until I restart the car then it's fine. I presume this is related to the O2 fault code.

[deni2316]

Originally Posted by arucano

IF you have a cat-less down pipe, you will need some type of "TUNE" to ignore the downstream (after cat) O2 sensor since that is used to check the cat efficiency. If there is no cat or bad cat, it will throw a check engine light with a cat efficiency code with standard software.

I suppose that wouldn't be the issue then since this is code for pre-cat O2 sensor that appears damaged.

[deni2316]

Originally Posted by TinCanSailor

Congrats on the M6 and welcome aboard; I see you are in 813 Bay. Rennen and Midnite tuning are good shops if you want to get deeper than what you father wants to get into.

Remove the plastic engine cover and look at the area to the rear of the engine and firewall. You'll see two pipes running down the back center as this is a Hot V design so tings are a little upside down from the traditionally v8's. Take a couple of pictures and uploaded them.

If the cable was off there is a chance the prev owner had downpipes on it and removed them before selling it.

Here is a photo from up top, I'm assuming this is stock and as you can see there is a cut in the O2 sensor itself. Hopefully switching that out and I'll be good to go.

[TinCanSailor]

Hey check out seller realoempart on ebay. They are down in Bradenton and have a lot of F1x M5/M6 parts off of wrecked M cars. You might be able to get a cable from them on the cheap and pretty quickly.

[Onpoint79]

How many O2 sensors does a 2013 650i xdrive take? The code reads I need the downstream sensor, but I don't know how many to purchase.

[arucano]

There is one downstream on each back. Would recommend replacing both if you have over 60K miles.