replaced primary o2 sensors, why am I still getting this code?

[kerrit]

I got this code for both banks a couple weeks, so I decided to replace my primary o2 sensors with new bosch units. I'm running an ESS 550 kit for 1500 miles so far with cold start delete. One of the sensors I pulled out was pretty fouled, the other looks decent. One other issue I just resolved was a leaky bypass valve, causing my car to run very rich since i put the blower on. I tightened it and the car runs WAY smoother.

I reset the codes and cleared adaptations and this came back:

Code 272C Lambda sensor driver diagnostic heating NKAT Bank 1

If it were a fuse problem I would expect to get warnings for all o2 sensors.. so there must be something else wrong with the car contributing to this issue with brand new sensors.

Does cold start delete affect the warmup time for o2 sensors? Cold start has been deleted for a while, so I would have expected this issue sooner if that was the case.

Is there anything on the fuel delivery or ignition side that could contribute to an o2 sensor not heating up in the time specified by the factory ecu parameters?

I'm wondering if the engine is too rich on bank 1 on startup, the o2 sensor may not heat up fast enough?

Trying to think of scenarios to where this code could occur after new o2 sensor install....

[edwinm3]

It's gotta be something to do with the tune, I'm not supercharged but tuned, had the same issue all I had to do was ask the tuner which by the way was great as always and he sent me a new more emmissions friendly tune and since then I haven't had any more of those codes come up.

I believe cold start does have something to do with it

[kerrit]

Update: I suspect I still have a vaccum leak somewhere or the ICV is going out. I'm smelling an oily intake smell through my vents on startup for a few seconds which I would think would point to a vac leak. Also, if the car has been sitting for <3-4 hours I get bouncy idle on startup that dips as low as 200 rpms and up to 800 for about 5 seconds.

I'm going to fix those issues, and then contact ESS if not resolved. I would think extremely rich conditions on startup could cause the o2's to not warm up fast enough, triggering the CEL.

Does anyone concur?

[Beemdog]

A vacuum gauge would be a helpful tool here. A vacuum leak would normally pull air into the intake so I'm unclear on the oily smell in relation to a vac leak... also, the vacuum leak would lead to a lean condition as opposed to an extremely rich condition.
A sparkplug read would show a white/lean condition after idling with a vacuum leak.

If only at start-up (and immediately following), the fuel tank vent valve is one other suspect. Another common failure point for idle symptoms is the low fuel pressure sensor.

[BPMSport]

Originally Posted by edwinm3

It's gotta be something to do with the tune, I'm not supercharged but tuned, had the same issue all I had to do was ask the tuner which by the way was great as always and he sent me a new more emmissions friendly tune and since then I haven't had any more of those codes come up.

I believe cold start does have something to do with it

Deleting faults is not a more "emissions friendly" tune, it's less emissions friendly. Removing faults just leads to masking potential problems and higher emissions. I highly doubt it's anything with the OPs tune. Beemdogs post is spot on, and idle jumping sounds like a vacuum/ICV issue to me.

An NA car should run without triggering ANY faults period, with every fault code left turned on and in tact. Otherwise there is an issue with the car. The fault the OP has is likely not related to the S/C.

[edwinm3]

Originally Posted by Mike Benvo

Deleting faults is not a more "emissions friendly" tune, it's less emissions friendly. Removing faults just leads to masking potential problems and higher emissions. I highly doubt it's anything with the OPs tune. Beemdogs post is spot on, and idle jumping sounds like a vacuum/ICV issue to me.

An NA car should run without triggering ANY faults period, with every fault code left turned on and in tact. Otherwise there is an issue with the car. The fault the OP has is likely not related to the S/C.

I don't think I said anything about deleting faults, it needed tweaking I guess. IIRC same thing happened when I had the 08 E90 with the previous tuner, something to do with it seeing something out of range when decelerating.

[terahertz]

Originally Posted by Mike Benvo

Deleting faults is not a more "emissions friendly" tune, it's less emissions friendly. Removing faults just leads to masking potential problems and higher emissions. I highly doubt it's anything with the OPs tune. Beemdogs post is spot on, and idle jumping sounds like a vacuum/ICV issue to me.

An NA car should run without triggering ANY faults period, with every fault code left turned on and in tact. Otherwise there is an issue with the car. The fault the OP has is likely not related to the S/C.

Mike, even with cold start on? I'm having 2728 and 2729 when I read the codes, but no CEL.

[Jonnykin]

Both My Pre-Cat sensors are toast. Dealership stated that the old O2 sensors are prone to failure after about 60k KM's. BMW has apparently replaced the sensors with a new part number and there is a ECU upgrade to go along with them. (release in the spring I'm told)