[BuellsterR1]

Hey guys,

My car is currently equipped with an OFT stage 2 tune with DCI/DP/IC. As of lately, I've been having this on going cel (P2C32) issue that keeps popping up every couple of days after clearing the code. The code is defined by "bank 2 fuel trim too lean." As of a lately, I've replaced the bank 2 pre cat O2 sensor and all new NGK plugs that were related to other problems. As of now, the car feels strong without any hiccups but this codes keeps randomly appearing.

Here is a log of a 3rd gear pull. I notice that my bank 2 fuel trims are about 10 points higher on average opposed to bank 1.

http://datazap.me/u/liem/after-spark...9&zoom=214-354

I checked all connections on the intake side of the bank 2 turbo for any leaks and everything seems to be in place. At this point, I'm wondering if its a good idea to change the fueling tables on bank 2 in the OFT to help mirror it to bank 1? If so, can someone point me in the right direction on how to do this??

Thanks,
Liem

[ragingpanda]

I'm having the same issue, bump.

[Ingeniator]

Originally Posted by BuellsterR1

Hey guys,

My car is currently equipped with an OFT stage 2 tune with DCI/DP/IC. As of lately, I've been having this on going cel (P2C32) issue that keeps popping up every couple of days after clearing the code. The code is defined by "bank 2 fuel trim too lean." As of a lately, I've replaced the bank 2 post cat O2 sensor and all new NGK plugs that were related to other problems. As of now, the car feels strong without any hiccups but this codes keeps randomly appearing.

Here is a log of a 3rd gear pull. I notice that my bank 2 fuel trims are about 10 points higher on average opposed to bank 1.

http://datazap.me/u/liem/after-spark...9&zoom=214-354

I checked all connections on the intake side of the bank 2 turbo for any leaks and everything seems to be in place. At this point, I'm wondering if its a good idea to change the fueling tables on bank 2 in the OFT to help mirror it to bank 1? If so, can someone point me in the right direction on how to do this??

Thanks,
Liem

Originally Posted by ragingpanda

I'm having the same issue, bump.

Pre cat O2 controls fuelling. If you had a bad rear 02 it could've thrown the pre cat out of calibration. You will need to reset adaptations to get it to re calibrate. Also ensure you are not running a o2sim also called dpfix as it will cause similar issues for the same reason.

[BuellsterR1]

Ok, so I took it upon myself to learn how to tune or realistically, have a fundamental understanding on what these particular maps do and what the numbers correspond to when plotted together. Basically, I'm tinkering with the fuel maps and have an understanding that the y-axis is rpm and the x-axis is load. Given the fact that I'm only concerned about the logs under load at this point, I'm only focused on anything more than 80% load. Therefore, I made some adjustments and was hoping for some feed back from the more knowledgeable guys.

Here is a log with the fuel scalar set to 1.03 on bank 1 and 1.11 on bank 2. I manage to get both the fuel trims on both banks relatively matched to each other while under load. Also, the range for on boost is -4 to 10 which through research, is good.

http://www.datazap.me/u/liem/stage2c...&zoom=998-1075

Here is the log after from which I tried to richen up the fuel maps on bank 2 by 0.9 on anything north of 80% load and 4,000 rpms. I did this to close the gap on bank 1 since it looked like I was about 0.75 AFR off throughout the previous 3rd gear pulls on past logs. It didn't look so good as I encountered an increased AFR on bank 1 and basically no change on bank 2. I made sure I only changed bank 2's fuel maps so now, I don't know what's going on. Also, if you zoom out of my log, you'll notice on later pulls that both O2 sensor feed backs would drop to zero at any point causing the AFRs to go nuts.

http://www.datazap.me/u/liem/stage2c...zoom=1783-1867

What do you guys think?? Any type of feedback would be great.

I'm now wondering if this is a stage 2 problem and am currently in the process of flashing back to stage 1 and logging.

I'll keep this thread updated..

[BuellsterR1]

I should make note that this is my girlfriend's car and she pretty much drives it conservatively. Basically, she never exceeds 4,000 rpms and is lucky to even hit 10 psi even though it's tuned. The reason I point this out is because the CEL (Bank 2 fuel trim too lean) almost always pops up when she is driving.

Could this be a part throttle map issue all along??
Were the O2 sensors installed on the wrong banks after the DP install?

[BuellsterR1]

Originally Posted by Ingeniator

Pre cat O2 controls fuelling. If you had a bad rear 02 it could've thrown the pre cat out of calibration. You will need to reset adaptations to get it to re calibrate. Also ensure you are not running a o2sim also called dpfix as it will cause similar issues for the same reason.

Thanks for the info.

I'll look into the rear O2 sensor to see if it's functioning correctly. Also, I'm running downpipes with decoded cat codes off the OpenFlash tablet. For some reason, the OFT keeps giving me errors when trying to reset any parameters such as lambda, afr, dme...ect.

[BuellsterR1]

Update...

I ended up switching back to my previous fuel scalar (bank 1 = 1.03, bank 2 = 1.10) only this time, richening up the fuel map on bank 1 to raise the AFR on bank 2 to level them out. I understand this is counter intuitive but it worked. I now believe that either my fuel maps for bank 1 is labeled wrong in the OFT when it should be bank 2, or my O2 sensors are mixed up.

Here is my latest log. The seriously car feels like it pick up 10 hp after these adjustments and is smooth as silk when pulling to redline. AFR are somewhat mirrored, fuel trims are within 2-3 points from each other with no drops (zeroed out), and timing gradually builds and hits targets. I used to get timing pulls up till 4,000 rpms with a max of 7 near redline but now, it nicely build. The believe the increase in timing is where the extra 10 hp is coming from.

http://www.datazap.me/u/liem/stage2c...zoom=2265-2377

I'll update me if this code comes back. Otherwise, this was somewhat a blessing in disquise as my car never felt stronger. Understanding the basics of tuning feels goods....for now that is.

[Ingeniator]

Originally Posted by BuellsterR1

Update...

I ended up switching back to my previous fuel scalar (bank 1 = 1.03, bank 2 = 1.10) only this time, richening up the fuel map on bank 1 to raise the AFR on bank 2 to level them out. I understand this is counter intuitive but it worked. I now believe that either my fuel maps for bank 1 is labeled wrong in the OFT when it should be bank 2, or my O2 sensors are mixed up.

Here is my latest log. The seriously car feels like it pick up 10 hp after these adjustments and is smooth as silk when pulling to redline. AFR are somewhat mirrored, fuel trims are within 2-3 points from each other with no drops (zeroed out), and timing gradually builds and hits targets. I used to get timing pulls up till 4,000 rpms with a max of 7 near redline but now, it nicely build. The believe the increase in timing is where the extra 10 hp is coming from.

http://www.datazap.me/u/liem/stage2c...zoom=2265-2377

I'll update me if this code comes back. Otherwise, this was somewhat a blessing in disquise as my car never felt stronger. Understanding the basics of tuning feels goods....for now that is.

Maybe someone else will chime in also. But I seem to remember an issue like this on the OFT prior to the last couple of firmware revisions. I think it may have been something upside down though rather than banks being switched. Wouldn't hurt to double check your on the newest revision.

[BuellsterR1]

Originally Posted by Ingeniator

Maybe someone else will chime in also. But I seem to remember an issue like this on the OFT prior to the last couple of firmware revisions. I think it may have been something upside down though rather than banks being switched. Wouldn't hurt to double check your on the newest revision.

All versions are current. OF Manager is V1.07 and maps are V1.05.

I finally decided to add the OFT upgraded features that enables one to log new/more channels. This was great as I was able to follow up on your notion that the rear O2 sensors might be the culprit. Guess what...I think your right man!

Here is a log of me just cruising to get lunch...

http://www.datazap.me/u/liem/bank2re...zoom=7499-9791

As you can see, the rear bank 2 O2 is functioning lazy and the range of sweep is pretty much non existent on part throttle cruising. Since it looks bias and the range is no less then 0.6+ volts, this would mean a rich fuel signal which made things more confusing as my constant CEL indicates a LEAN fuel trim on bank 2.

On the way home from lunch, I was lucky enough to have the CEL come on and as soon as I saw it, I glanced over at the OFT while the channels were active and notice that the rear bank 2 O2 sensor was dead and flat lined at 0 while bank 1 was actively cycling. If the ECU is registering a zero reading as a lean signal, which it is, this made more sense and is more then enough to convince me that the rear O2 sensor is most likely the culprit. Anyhow, I appreciate your help Ingeniator. I would have never suspected the rear O2 to have any part in fuel trims. I always thought the only purpose was to monitor the catalytic converters health.

My next step is to swap O2 sensors to see if the CEL follows the questionable one. I might just say they hell with it and just order a new one. I'll keep you updated..

[BuellsterR1]

It turns out, you can't swap rear O2 sensors as the male and female connectors have offset notches.

I went ahead and back probed the pre cat O2 sensors on both banks. Bank 1 read fine and the range was fluctuating from 2.1V - 2.9V at idle. Bank 2 had a range of 2.70V - 2.79V which is bias LEAN for a A/F sensor. I now believe this is where the ECU is sourcing its fault code. Here are some troubling questions....

1. If Bank 2 sensor 1 is bias lean with a range of 2.70V - 2.79V, why would bank 2 sensor 2 read bias rich at 0.71V - 0.78V when I have VSFR downpipes?

2. Here is a quote from an online source explaining how an A/F sensor works, "Missfires due to a malfunctioning or underpowered ignition or an extremely rich mixture can cause false lean readings because unburned liquid fuel in droplets or a mist cannot enter the small hole leading to the sensors pump cell." This would make sense on why my sensor 1 is lean and sensor 2 is rich. Any thoughts or experiences??

I do have occasional white smoke coming out the exhaust whether it's on cold start or at operating temperatures. This series of smoke lingers for about a minute and disappears. This will happen roughly once a week. All fuel injectors were updated 5,000 miles ago and I haven't had a problem until now.

[C.Pop]

Not sure, but bump for a well thought out thread and good troublshooting.

[Ingeniator]

Originally Posted by BuellsterR1

It turns out, you can't swap rear O2 sensors as the male and female connectors have offset notches.

I went ahead and back probed the pre cat O2 sensors on both banks. Bank 1 read fine and the range was fluctuating from 2.1V - 2.9V at idle. Bank 2 had a range of 2.70V - 2.79V which is bias LEAN for a A/F sensor. I now believe this is where the ECU is sourcing its fault code. Here are some troubling questions....

1. If Bank 2 sensor 1 is bias lean with a range of 2.70V - 2.79V, why would bank 2 sensor 2 read bias rich at 0.71V - 0.78V when I have VSFR downpipes?

2. Here is a quote from an online source explaining how an A/F sensor works, "Missfires due to a malfunctioning or underpowered ignition or an extremely rich mixture can cause false lean readings because unburned liquid fuel in droplets or a mist cannot enter the small hole leading to the sensors pump cell." This would make sense on why my sensor 1 is lean and sensor 2 is rich. Any thoughts or experiences??

I do have occasional white smoke coming out the exhaust whether it's on cold start or at operating temperatures. This series of smoke lingers for about a minute and disappears. This will happen roughly once a week. All fuel injectors were updated 5,000 miles ago and I haven't had a problem until now.

The bosch wideband that is used in our cars is calibrated by the narrow band O2 in the after cat position. It uses the fluctuation to verify the reading. Most after market O2 kits that use bosh sensors use free air calibration BMW went with a running calibration using the rear sensor to adjust the front sensor. If you suspect the rear sensor is bad as it appears to be then this would cause the dme to change the fuelling to bring it back into an incorrect AFR(DME sees on target) as the O2 signal is incorrectly interpreted.

[BuellsterR1]

Originally Posted by Ingeniator

The bosch wideband that is used in our cars is calibrated by the narrow band O2 in the after cat position. It uses the fluctuation to verify the reading. Most after market O2 kits that use bosh sensors use free air calibration BMW went with a running calibration using the rear sensor to adjust the front sensor. If you suspect the rear sensor is bad as it appears to be then this would cause the dme to change the fuelling to bring it back into an incorrect AFR(DME sees on target) as the O2 signal is incorrectly interpreted.

I see!

Thanks for the info as this is all making more sense now. The rear O2 sensor is relatively cheap to just replace and pray so it's ordered and on its way.

I think my final check prior to installing the new rear o2 sensor is to just remove the prongs at the male connector from questionable sensor and swap it with the other to verify its activity at the other bank.

Updates to follow but as for now, I have tune in to watch USA demolish Belgium in the cup. USA!! USA!! USA!!

[RnmEvo9]

Originally Posted by BuellsterR1

I see!

Thanks for the info as this is all making more sense now. The rear O2 sensor is relatively cheap to just replace and pray so it's ordered and on its way.

I think my final check prior to installing the new rear o2 sensor is to just remove the prongs at the male connector from questionable sensor and swap it with the other to verify its activity at the other bank.

Updates to follow but as for now, I have tune in to watch USA demolish Belgium in the cup. USA!! USA!! USA!!

Where did you order your rear o2 sensor from? My rear bank o2 sensor was semi stripped when it was removed from my stock downpipes which leads me to believe why I am now throwing 2c32 and 2c2c on my car.

Thanks!

[BuellsterR1]

Originally Posted by RnmEvo9

Where did you order your rear o2 sensor from? My rear bank o2 sensor was semi stripped when it was removed from my stock downpipes which leads me to believe why I am now throwing 2c32 and 2c2c on my car.

Thanks!

I purchased a Bosch 15733 O2 sensor off ebay for $30 shipped. You can find it at your local Autozone for $68. I simply spliced and soldered the old O2 sensor connector onto the new Bosch sensor. If you can manage to get the prongs out of the old connector and onto the new sensor wires, I recommend doing it that way as it's a cleaner install. I didn't have any success in doing it this way and pretty much murdered one of my prongs trying to get it to slide out. After about 10 minutes and not wanting the damage to escalate any further, I resorted to the splice and solder method which worked good out so far.

DO NOT use the splice and solder method on the pre cat (front) O2 sensors as there is a calibration resistor built in. You can however, use the Bosch 17098 A/F sensor on both bank 1 and bank 2. The only difference when using this sensor in bank 2 is the extra length of wire which can be easily coiled up and tucked away.

[BuellsterR1]

SOLVED!!!!!!

I was able to install the bank 2 rear O2 sensor yesterday using a splice and solder method. After doing so, I was disappointed as there was no change in the output reading. Bank 2 rear O2 kept reading in the range of 0.7OV - 0.79V at constant throttle while bank 1 rear O2 was fluctuating from 0.1V - 0.9V. The only time bank 2 would wonder out of this range was when I lifted off the throttle (0V - 0.1V) or when I pegged the throttle (0.85V - 0.95V). At this point, I was stumped. I proceeded to disconnect pre and post cat O2 sensors to verify the OFT was displaying the right channels in their respective places. It was so I called it a night.

Today, the only thing left was Ingeniator's advice on resetting the adaptations but I couldn't get the OFT to complete this task. It was always giving me errors when prompting the command. This lead me to do a search on resetting adaptations and I stumbled upon a thread about a 335i that wouldn't start after resetting this DME while the car was off. This was when I realize that all this time, I was trying to reset adaptations while the engine was running. Therefore, I tried it with the ignition on engine off and finally, success!!! I ended up resetting everything I could on the OFT except the transmission (I have a 6spd manual) and the battery. After doing so, I started the engine and let it idle for 5 minutes while viewing the bank 2 rear O2 sensor channel. After about 2 minutes, it started to cycle it's full range from 0.1-0.9V but was still sluggish compared to bank 1. After driving it for 5 minutes, it started cycling at the same rate as bank 1 and that's all she wrote fellas.

Here is the log to confirm...

http://www.datazap.me/u/liem/adaptat...zoom=3653-4673

I did notice that under load, my bank 1 fuel trims are about 10 points off of bank 2. I believe this is a result of me trying to put a band aid on the source of this problem by changing fuel scalars and fuel maps initially. I'm going to switch back to default setting and go from there.

Kudos to Ingeniator for your help man. You were on point from the get go and I really appreciate it.

I'll update if this matter comes back. Otherwise, I hope this will help other in the future.

[Ingeniator]

No problem glad you got it fixed.

[AMERICUS]

Buellster, first congrats! Thanks for this informative thread and impeccable timing! So I ordered a rear o2 from Amazon (prime) and will splice the rear one this weekend. I am also goign to order the front one, but want to clarify. The Bosch 17098 will work for bank 2 front o2 sensor from my other thread that you directed me here for right? Will this replace the BMW 11787558055 on real oem? Just want to make sure it is the same one with the exception of wire length.

http://www.realoem.com/bmw/showparts...86&hg=18&fg=10

Originally Posted by BuellsterR1

I purchased a Bosch 15733 O2 sensor off ebay for $30 shipped. You can find it at your local Autozone for $68. I simply spliced and soldered the old O2 sensor connector onto the new Bosch sensor. If you can manage to get the prongs out of the old connector and onto the new sensor wires, I recommend doing it that way as it's a cleaner install. I didn't have any success in doing it this way and pretty much murdered one of my prongs trying to get it to slide out. After about 10 minutes and not wanting the damage to escalate any further, I resorted to the splice and solder method which worked good out so far.

DO NOT use the splice and solder method on the pre cat (front) O2 sensors as there is a calibration resistor built in. You can however, use the Bosch 17098 A/F sensor on both bank 1 and bank 2. The only difference when using this sensor in bank 2 is the extra length of wire which can be easily coiled up and tucked away.

[BuellsterR1]

In short, yes. The Bosch 17098 will work for both bank 1 and bank 2 pre cat.

Refer to this thread for specifics.....

http://www.e90post.com/forums/showthread.php?t=726481

Once complete, make sure you reset adaptations in lamda, afr, and dme using INPA, OFT, or your Cobb if it allows it. I believe this was my underlying issue all along.

Keep us updated..

[itsaug]

Hate to bring this thing back to life, but I just want to make sure I'm covering all my bases. This same P2C32 code keeps popping up every few weeks (car is driven maybe twice a week as I have a business car that's my primary car). Currently running Cobb stage 2+ aggressive ST, catless downpipes, 5" stepped intercooler, and ER chargepipe with tial bov. 2012 335is with 30k on the clock and was bought last year CPO off lease. Log is posted below showing the STFTs are off by about 10 pts throughout the rpm band. I just want to know if I should remove the Cobb before taking it in to bmw or if I can leave it on to have the lambda and air/fuel adaptations reset at the dealer(yes I need to get a BT cable)?

http://www.datazap.me/u/itsaug/3rd-4...0&data=1-6-7-8

[kalamokid]

Hey all having same problem......any advice? Cobb wit catless downpipe and bm downpipe fix