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YOUR RESEARCHLosing my mind - 02 Sensors from hell
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Clean (luckily no debris in pickup screen), reapplied
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Performed · outcome unconfirmed · Original poster
- dropped sump pan and cleaned (luckily no debris in pickup screen), reapplied with Permatex "the right stuff" - no leaks
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Performed · outcome unconfirmed · Original poster
Header studs that meet exhaust drilled out and replaced with bolts and new gaskets.
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Performed · outcome unconfirmed · Original poster
I still don't understand why BMW designated the two door as the M4 and the four door as the M3 - I swear that was a mistake and they just ran with it...
Use basin wrench, intermittent heat, and lots of pb blaster
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I use a basin wrench, intermittent heat, and lots of PB blaster to get the O2 sensors out.
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Suggestion · Original poster
Everything was DIY except for most recent o2 sensor work (shop had to cut bungs out and weld new ones, also had to cut clamps where cat pipe meets muffler and install new ones from dealer - they look clean...).
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I cannot get them out. The exhaust needs to come out of the car.
If I remove the headers and the two bolts holding the back boxes, wouldn't the whole exhaust drop out in one piece? Anyone know how much it weighs?
I've done just about anything you can think of to try and get them out. I don't see another option aside from cutting the bungs out and welding new ones in place, which is what they'll probably do.
Also I don't want to drive the car to the shop because I just put new plugs in - worried about them getting fouled. Am I being too "OCD" with that or do you think it's safe to drive? I have really banged up the pre and post cat o2's on bank 1 so they definitely will not work.
Disconnect both sensors on bank 1 from the wiring loom and drive there. You won't foul the plugs and you won't destroy the cat on bank 1 either.
The ecu will mirror the injector time of bank2 on bank1 and you'll probably get a CEL but nothing gets damaged.
I have never had a problem getting them out, even 30 years later. Propane torch won't get them hot enough. You need oxyacatylene. Heat the bungs until they are glowing all around and unscrew the sensor. An exhaust shop should be able to do this for you.
bank 2�s precat 02 is dead though. Are you sure?
ah ok - yeah taking it there tomo. I was using a propane torch. went through a can of propane on 1 sensor. Don�t know if it�ll matter though because my 22mm 02 socket rounded out the corners on the nut. Only way I see it happening now is the heat you mention, channel locks and a pipe big enough to fit over the channel locks. Or they cut the bungs out which is what they probably do anyway for time.
Unplug that as well then.
I am still sure you won't damage anything. It will run open loop and base fuel on the MAF signal and rpm. The engine will still run close enough to stochiometric at part throttle for the cats to not suffer damage (they'll actually work).
Exhaust work is the worst. While all header bolts came out fine on my car, the shop that quoted me some service that required removing the headers said almost 1/2 the time, at least 1 stubborn bolt needs to be drilled out.
Better still, use exhaust studs of a BMW with 8mm studs and the corresponding nuts and you'll never have to drill out any header bolts again
BMW Exhaust Manifold Stud - Genuine BMW p/n 11627583110
Copper Exhaust Lock Nut, M8 - 18307620549
I use a basin wrench, intermittent heat, and lots of PB blaster to get the O2 sensors out. The split O2 sensor sockets always strip out. If you get a decent basin wrench with hardened jaws, you can grunt the sensors out. Get one with a long (telescoping) handle for best results. The harder you pull, the harder the jaws bite...
I put my hands up last night, 5CHN3LL. Car's at the exhaust shop as we speak. I've worked with these guys a few times in the past and they do a nice job. I told him to give a go at the trans fill plug too as I stripped that out. I did tell him not to drill it out.
If they can't get it maybe I'll tell them about this. Don't want to tell a mechanic what to do though. A fine balancing act there.
Previous owner or a poorly trained mechanic absolutely torqued my trans filler plug in, I couldn't budge it. I did the hands in the air thing and took it to my Indy. He sorted it with a knowing smile.
Never....Ever use a Oxygen sensor socket or crows foot style O2 sensor tool to remove a BAD O2 sensor.Cut the harness off and slide a deep 22mm or 7/8's socket over the shell of the sensor.Heat and time is your best friend if sensor is tight.Drive the car.Soak it in your favorite brand of "nut buster".Rinse and repeat for a couple of days.let it sit overnite and try to remove.Still to tight? Do it some more. I have never found an O2 sensor that I couldn't get out with only a extra long 3/8's drive ratchet wrench or 22mm box end wrench.
Damn - Tom just called me (owner of the shop) -
They got those things cherry red and they would not budge. He tried all 4 too - it's not even just the one I stripped. He did get the trans fill plug out though with an air chisel.
What he's going to do is take everything out post headers. He'll cut the 3 studs on each side where the headers meet the cats to get them out and re-tap with bolts and nuts (I told him to just do this from the getco and forget about trying to get the current ones off - I'd rather have bolts there anyway).
Then he'll cut the bungs out with a plasma cutter and weld in new ones...........
Edit- Actually might have 'em do a gundo while it's out.......... we'll see -
I had one that bent the 02 socket and took the threads from the cat pipe out with it… was awesome.
I have felt a similar pain as you and send my sympathies.
Damn. I�ll be working on replacing a cat in the next few days. If these sensors start giving me troubles I�ll be using these tips before I get too crazy�.
If / when you get them out put some anti seize on the threads when you reinstall.
After I bent the socket, an open ended and a 3 ft breaker bar were what got it, and the threads out.
This process also included one of the longest unbroken streaks of foul language I have ever demonstrated� and that�s saying something.
I don�t think you can go wrong with 1.75� or 1.5� size cross pipe. I don�t remember what I did, but I know it was 2� like some folks choose. There�s a bunch of old threads on this.
i usually reserve the foul language for the golf course. I�m more of a deep grunter/yeller under the car.
that said there really is nothing like a well executed F bomb.
We sell brand new parts with added ooomph for these very situations! lol. When I bought my 986S I flew to Florida to find a perfect one so I have a chance. Even my 996 was a Califonia car (but I lived there at the time) and luckily everything came apart easily on both whenever needed.
As you can imagine, we've seen neayl everything here at SOUL with cars from the Northeast. The frustration you are experiencing is not to be underestimated. I feel for our techs sometimes an this is what they do all day long. lol.
Glad you are making progress, I highly recommend the GUNDO and some
@Soul Performance
high-flow cats... but I'm in sales at the end of the day!
Dave @ SOUL
Haha, thanks Dave - I am in sales as well and certainly appreciate it!
Edit- on second thought.... do you think the cats will get destroyed because of the shavings from the cut? I don't see a way for them to get all of the shavings out post-cut other than to drive the car and blow them through everything.
I have plans in the future to use your product. My brother added your valved system to his 718 Spyder. It�s more glorious than his stock Gt3 Touring. Real world problems 🙃
My car that I�m removing Sensors is from Florida. It�s pretty clean underneath (67k miles) 🤞
I've just done mine , I heated the exhaust with a plumbers gas torch around the area where the sensor is until it's like glowing red then they do come out with a loud squeak , I was the same before I tried this, they wouldn't budge with any release agent !
Couple of bad photos for the thread. Got everything sorted. Everything was DIY except for most recent o2 sensor work (shop had to cut bungs out and weld new ones, also had to cut clamps where cat pipe meets muffler and install new ones from dealer - they look clean...).
Love this car again...
So far I've done the following:
- driven ~15K miles in almost a year
- changed oil twice (Liqui Molly Leif-Htech 5w-40)
- transaxle fluid change and aluminum plugs with washers
- new tires (Hankook Ventus V12 summers - love these tires - was very noticeable change over continental contact extremes)
- rear rotors and pads (Zimmermans)
- LN oil drain plug
- dropped sump pan and cleaned (luckily no debris in pickup screen), reapplied with Permatex "the right stuff" - no leaks
- Coolant flush and change with Porsche pink/distilled water mix
- AC condensers changed and system vacuumed. New freon and oil for compressor. Ice cold now.
- TB, ICV and maf cleaning
- new intake air filter
- all four o2 sensors with new bungs welded in. Header studs that meet exhaust drilled out and replaced with bolts and new gaskets.
- new Bosch spark plugs and Bremi Coils (did this with just an E10 socket and the wheels and exhaust on - it
is
possible)
- new bank 2 variocam seal
- washed/interior conditioned and vacuumed at least 1x/month
- cleaned and reinstalled sump pan skid plate (previous owner installed, was just a tad dirty)
- clear drain holes next to battery with shop vac
And couple of cool things I've noticed about this car is that I have the 4-spoke steering wheel and sport seats (the ones with the horizontal seams at your butt). It's a full leather interior and also has an LSD per the codes on the frunk.
I have some plans for it, but am going to just enjoy it for a bit. It is completely stock as it sits now.
Coworkers new M4... I still don't understand why BMW designated the two door as the M4 and the four door as the M3 - I swear that was a mistake and they just ran with it... Makes no sense.
what do you mean by original? E30?
I had a few e36 M3s and one e46 M3. Had a cosmos on dove e36/5 with an AA supercharger kit (stg 2 w/intercooler) I found on CL - that thing was quick� lots of fun.
Edit- found a vid (attached)- uggg listen to that blowoff valve in the beginning�. I miss it
