Oxygen sensors for 1999 M3, any options other than BMW?

[E36 Em Tree]

Before there was NTK spark plugs for like 70 bucks and then they were 100... but just got back in the game and now they're backordered/NLA.

What's everyone using got O2 sensors pre/post cat? I don't wanna spend 600 for front O2 sensors or 1200 in total.

Is there another go-to supplier of O2 sensors that this platform uses now? Couldn't find anything on bimmerworld, fcp or ecs besides genuine BMW at $300ish.

[shogun]

some options
pre cat 11781437943 SIEMENS/L=990MM

Bosch Art.-Nr.: F00E261264 1020 mm
Hella Art.-Nr.: 6pa 358 066-101 1000 mm
NTY Art.-Nr.: ESL-BM-005 for SIEMENS, 990 mm
Vemo Art.-Nr.: V20-76-0052 650 mm
FAE Art.-Nr.: 77190 970 mm


post cat 11781427884 SIEMENS/L=990MM

options
NGK Art.-Nr.: 0486 968 mm
Continental/VDO Art.-Nr.: A2C59513343Z 990 mm
Bosch Art.-Nr.: F00E261264 1020 mm
Hella Art.-Nr.: 6pa 358 066-101 1000 mm
NTY Art.-Nr.: ESL-BM-005 for SIEMENS, 990 mm
Vemo Art.-Nr.: V20-76-0036 970 mm
Denso Direct Fit Art.-Nr.: DOX-1368 ,Siemens/NTK,
Delphi Art.-Nr.: es11051-12b1 990 mm

[E36 Em Tree]

The pre and post cats are different? I thought they were the same IIRC? it's been a while so maybe I was wrong buying 4 of the same.

[pbonsalb]

You can’t use regular ones because these are titanium oxide and read differently. But if you can find titanium oxide with a different harness you could cut and splice. Maybe from a different BMW? My E36 M3 has the same titanium oxide front and rear O2 but different length harnesses. My E90 M3 had full time wide band front O2 but the rears looked like the ones on my E36 M3 though I never verified they were titanium oxide.

[E36 Em Tree]

You can’t use regular ones because these are titanium oxide and read differently. But if you can find titanium oxide with a different harness you could cut and splice. Maybe from a different BMW? My E36 M3 has the same titanium oxide front and rear O2 but different length harnesses. My E90 M3 had full time wide band front O2 but the rears looked like the ones on my E36 M3 though I never verified they were titanium oxide.

Ah that's weird. The last shop that serviced this car used 4 same "Oem oxygen sensors" at 293$/each which I'm guessing is genuine bmw. I go to fcp euro and ecs to verify parts too and fcp even states all 4 are the same. https://www.fcpeuro.com/products/bmw...rear-e36-25013

I'll have to try two pre cat ones first since those measure AFR right? I'm failing smog so need to do a tune up anyways. Spark plugs are first and O2 sensors next. Just going down the line of maintenance rn.

[bluptgm3]

Load the last seven characters of your VIN in www.realoem.com and look thru the diagrams and determine your OEM part number requirements.


My MY 04/1999 M3 S52 uses
Front
11781437943 Oxygen sensor
SIEMENS/L=990MM

Rear
11781427884 Oxygen sensor
SIEMENS/L=990MM

But it looks like 11781437943 supersedes 11781427884 in the two front positions per www.realoem.com

… and I believe those to be
Bosch 13884
NTK 25013

NTK produces the Bosch sensors, both are going Backordered/NLA….

[E36 Em Tree]

Load the last seven characters of your VIN in www.realoem.com and look thru the diagrams and determine your OEM part number requirements.


My MY 04/1999 M3 S52 uses
Front
11781437943 Oxygen sensor
SIEMENS/L=990MM

Rear
11781427884 Oxygen sensor
SIEMENS/L=990MM

Screenshot_20230201-201741_Chrome.jpg

Thanks. I have a 99 M3. Found mixed results when searching saying the 99 might use a different o2 sensors, 4 same or 2 different ones for pre/post cat. Still a little confused. Might just replace the front 2 for now and ask BMW what's the newest part.

Looks like 11781437943 is the pre cat and post cat now. Says this part supercedes the 11781427884 which was the post cat.

[bluptgm3]

Screenshot_20230201-201741_Chrome.jpg

Thanks. I have a 99 M3. Found mixed results when searching saying the 99 might use a different o2 sensors, 4 same or 2 different ones for pre/post cat. Still a little confused. Might just replace the front 2 for now and ask BMW what's the newest part.

Looks like 11781437943 is the pre cat and post cat now. Says this part supercedes the 11781427884 which was the post cat.

Ya, sorry I overlooked the Supersession Info.

Looks like the Rear Sensor 11781427884 is also Superseded by 11781437943.

You could try the Bosch 13884 which is equivalent to 11781427884.


And that doesn’t really help much, though the NTK part number 25013 is also listed as the same for pre-cat and post-cat. NTK built sensors for Bosch. My take-out forward O2s were stamped NTK


Here is the four wire universal splice in sensor from NTK on eBay






Between FLCAs, Guide Supports, and O2 Sensors these cars have all of a sudden become very expensive.

[E36 Em Tree]

Ya, sorry I overlooked the Supersession Info.

Looks like the Rear Sensor 11781427884 is also Superseded by 11781437943.


And that doesn’t really help much .

Between FLCAs, Guide Supports, and O2 Sensors these cars have all of a sudden become very expensive.

Yeah it seems going off the pre cars they're around 200 on ecs or fcp. It gets confusing cause you search the part number and it gives NLA or superceded parts.

But for future searches... there's vemo for 75 or bosch/etc for 200-300 for the pre vats. Still searching for the post jic it's different.

[Eric93se]

Was going to suggest Rockauto but they don't have much inventory for m3 o2 sensors. You should be able to find a quality brand under 100.

[pbonsalb]

That NTK universal looks like a good deal if it is titanium oxide, and it seems like it is.

[E36 Em Tree]

Thing that sucks about that is you gotta spice the wires to another one. Something I didn't wanna do to such a critical part of the exhaust and fuel mixture. Might just have to shell out 200/each. I thought there would be some cheap OEM plug n play alternative. Weirdly not.

[pbonsalb]

I’d splice for $40 instead of plug and play for $200.

[E36 Em Tree]

I’d splice for $40 instead of plug and play for $200.

I mean its definitely tempting haha but i hate anything electrical and would like the "simplest" route but it might come down to it.. or maybe buying the VEMO https://www.ecstuning.com/b-vemo-par...781437943~vai/

Does anyone happen to know what might happen if you used the post-cat or pre-cat in the wrong bung? Im throwing a rich fuel mixture (assuming this o2 sensor is the wrong one).

[E36 Em Tree]

ECS also has this disclaimer on their site for sensor 11781427884 (which you guys have said is for post-cat)

Oxygen Sensor 990mm - cure your poor gas mileage by replacing your worn oxygen sensors
For vehicles with production date up to 04/1998
Brand:
ES#: 27149
Mfg#: 11781427884

Contacted ECS just to see what their .02 was and they also confirmed that 943 did not ss 884 so maybe I'll have to order 2 new pre-cat sensors. The shop didnt put part #s down on the previous owners receipt so I'll have to assume (based on the 4 units they ordered at the same price) that they used 4 of the same oxygen sensors not knowing the E36 had 2 different sets.


Not to keep being annoying to everyone but at least this information wont go to waste when someone searches for new sensors. But these https://www.ecstuning.com/b-vemo-par...781437943~vai/ are from Germany and found an article by ECS saying they are sourced directly from them and same supplier as NTK and Bosch (https://www.northamericanmotoring.co...market-ok.html)

[pbonsalb]

Pre-cat definitely makes a difference if you get them reversed and it happens within a few minutes since the feedback is wrong as the computer continually adjusts the wrong cylinder banks until the engine runs poorly. Rear 02 mixed up will just throw a rear 02/cat code.

[E36 Em Tree]

That's what i figured. Im not throwing any codes besides failing emissions with high HC so I'll leave it for now. Im thinking they threw 4 pre-cat sensors into the car and I know the rear ones just test Cat efficiency (which is fine) due to my low Nox and low O2 coming out

[pbonsalb]

Their functions for the ECU differ, but the sensor is the same front and rear on the 328/M3 so they are interchangeable if the harnesses reach.

Did you try swapping the connections for the rears under the car where they connect? I’d clear adaptions as well if you have a scan tool that does. At least clear codes. If the code reappears then I am not sure what to do next. I have ruined O2 before banging on exhaust sections. I now remove them when I have to pound pipes together or apart.

[E36 Em Tree]

Their functions for the ECU differ, but the sensor is the same front and rear on the 328/M3 so they are interchangeable if the harnesses reach.

Did you try swapping the connections for the rears under the car where they connect? I’d clear adaptions as well if you have a scan tool that does. At least clear codes. If the code reappears then I am not sure what to do next. I have ruined O2 before banging on exhaust sections. I now remove them when I have to pound pipes together or apart.

Ah gotcha. I have no codes as of right now, but I did have the previous EVAP issues which i think have been solved with my brand new BMW gas cap. I'm thinking it also might be the purge valve (being stuck open). I still need to test them and then also need to swap it out just in case.

Will use some injector/fuel cleaner (or whatever additive) on a full tank and just smash on the gas to see if i can knock off some odl carbon or whatever. The car hasnt been driven much in the last few years. Maybe around 3k in 2 years between 2 owners

[pbonsalb]

A scan tool with BMW specific software, that can reset adaptions, give live readouts, and do some bidirectional testing should be on your tool list. Some who are good with computers download copies of the BMW software and buy a copy of the connector. It is the best route. But something like the Foxwell NT510 or 520 or 530 is pretty good for a self contained hand held at about $150, with one free brand specific module when you register it. Chose BMW/Mini

[E36 Em Tree]

A scan tool with BMW specific software, that can reset adaptions, give live readouts, and do some bidirectional testing should be on your tool list. Some who are good with computers download copies of the BMW software and buy a copy of the connector. It is the best route. But something like the Foxwell NT510 or 520 or 530 is pretty good for a self contained hand held at about $150, with one free brand specific module when you register it. Chose BMW/Mini

Just got hold of a Schawben(sp?) tool. i think i can extract the live data for the O2 sensors from that and see if voltage is the same readings for the respective area. Dont think im not using the search function or google haha just trying to get additional info and stuff before diving in again. Id rather do everything at once now before taking it back to the shop rather than going back... and forth.. back.. and forth.

While I have you here haha... is the fuel tank breather valve (purge control valve) supposed to be open without 12v?

Trying to troubleshoot multiple issues to get this thing SMOG ready and registered but a bunch of little things here and there need to be done to make it road worthy. (plugs, gas cap, maybe purge valve)

[pbonsalb]

I don’t know the answer to that question.

[Eric93se]

Personally I would pass on the splice sensors. I use rmeuropean a lot, they have Bosch for 160 free shipping, I would go for that.

[E36 Em Tree]

Personally I would pass on the splice sensors. I use rmeuropean a lot, they have Bosch for 160 free shipping, I would go for that.

$160-200 definitely beats 299+tax on ECS. Ill see if theres other stuff before pulling the trigger. VEMO is back ordered til April as well. Seems like theyre trying to phase out this car without providing necessary stuff to actually make it legal to drive.

[E36 Em Tree]

I think the concern with mixing the bank sensors is putting the wrong connection into the plug -> wrong bung hole. Youtube suggests one at a time to avoid this issue which makes sense haha.

FEBI top.
BMW bottom.

20230202_191732.jpg
20230202_185102.jpg

I did already have this fuel purge valve that I changed out. This one is a Febi. I switched it out for an OE BMW one which was $180 on fcp. The Febi has a 2021 manufacture date on it... I'm able to blow through the evap nipple and air comes out where it would go into the manifold suggesting it was broken. The new bmw one held a seal where I couldn't even blow through it.