[ApertureF30]

Greetings all:

I've been hanging around the forum for awhile, but this is my first post. I've recently gone BM3 stage 2 & XHP stage 2 with my 2018 330i xDrive. I was at stage 1 for some time, and the car ran beautifully (I had the OTS BM3 stage 1 tune along with the XHP stage 2 tune). However, since going OTS BM3 stage 2, I've been running into some issues.

My modifications are as follows: Evolution Racewerks charge pipe kit, Dinan carbon fiber intake, Active Autowerke catted down pipe, and an AWE axle-back exhaust. The car has 40,xxx miles on it.

Ever since going stage 2 (BM3, OTS tune), I've been experiencing a rough idle at start up, and recently a CEL for cylinder misfires. See below:

I've also recently done some data logging in Sport + and noticed some irregularities, specifically in ignition timing (between 2nd and 3rd gear), as well as MAF readings that make no sense (anywhere between 150lbs/min and 479lbs/min). There are also some large deltas between boost and target boost.

My logs can be found here:

https://datazap.me/u/aperturef30/201...otmod3-stage-2

https://datazap.me/u/aperturef30/201...ta=13-14-15-16 (This data log has some crazy ignition timing...)

I'm hoping that the collective knowledge of the forum can help me iron out some of the issues I'm experiencing on the BM3 OTS tune. I know that I likely need new spark plugs. I will likely also change the intake to either OEM or one with a MAF housing that is similar to OEM. I appreciate any advice in advance.

[sqwinny]

Timing corrections seem fine. Fueling seems fine. If going from 1 -> 2 only is the issue, might be worth looking at plugs and coils. Around 50-60k is where they need to be changed when tuned. Start there

[ApertureF30]

Thanks, I will be doing plugs and coils soon. I also re-flashed to the OTS 91 octane BM3 tune, despite running 93 octane fuel. Car seems a bit happier now, but I need to confirm with some logs.

[F36_Paul]

My car ran like crap with BM3 Stage 1, I really wanted to keep it but I had to just flash back to stock..it runs so much smoother on stock IDK what the issue is.

[ApertureF30]

That is strange indeed. My car seemed perfectly happy with the BM3 93 octane stage 1 tune. At that time, I had the Dinan intake, AWE axle-back, and Evolution Racewerks charge pipe, and it was perfectly smooth, idled fine at cold start-up, and made decent power. I've read that the Dinan intake may cause MAF reading issues, but I never had any of that at stage 1. It is strange that those issues suddenly showed up at stage 2. I will likely have the plugs and coils changed, and I might go back to the OEM down-pipe and run a custom tune from Jordan Tuned. I need reliability as this is my daily driver.

[mike@x-ph.com]

Originally Posted by ApertureF30

That is strange indeed. My car seemed perfectly happy with the BM3 93 octane stage 1 tune. At that time, I had the Dinan intake, AWE axle-back, and Evolution Racewerks charge pipe, and it was perfectly smooth, idled fine at cold start-up, and made decent power. I've read that the Dinan intake may cause MAF reading issues, but I never had any of that at stage 1. It is strange that those issues suddenly showed up at stage 2. I will likely have the plugs and coils changed, and I might go back to the OEM down-pipe and run a custom tune from Jordan Tuned. I need reliability as this is my daily driver.

Let us know how it goes

[ApertureF30]

I just had the plugs replaced with NGK 94201s, and the rough idle at cold start-up issue remains. Next up is replacing the Dinan intake with the OEM piece. I will do some data logging after that is installed and compare the MAF sensor readings between the Dinan and OEM. I have a feeling it will be a pronounced difference as the MAF readings right now are all sorts of messed up. Wish me luck.

[nh90crxsi]

Any updates?

[drapzzy]

Originally Posted by sqwinny

Timing corrections seem fine. Fueling seems fine. If going from 1 -> 2 only is the issue, might be worth looking at plugs and coils. Around 50-60k is where they need to be changed when tuned. Start there

Agree with this, rough idles and misfires can be as simple as just worn sparkplugs!

[ApertureF30]

Spark plugs have been replaced with NGKs, and the issue seemed to be a bit better for a couple of weeks, until I threw the same misfire codes at start-up. I'm still waiting to have the OEM intake re-installed. Maybe a custom tune is in order as well? I don't know.

[ApertureF30]

Update: I've reinstalled the OEM intake and cold start-ups are now much smoother with no rough idle or misfire CELs. Here's my takeaway from all this: the Dinan CF intake worked just fine when I had the OEM downpipe and Bootmod3 93 octane stage 1 tune. I ran it for several months without any issues. However, with the Active Autowerke downpipe and the Bootmod3 93 and 91 octane stage 2 tunes, I had issues with a rough idle at cold start-ups and misfire CELs after cold start-ups. I have yet to do any datalogging to confirm that the MAF readings are back to normal from their values in the high hundreds at WOT when running the Dinan intake, and I will do so soon. Anyone want a slightly used Dinan CF intake for their stage 1 or stock 330i B46? ;-)

[ApertureF30]

Update to the update: another misfire CEL today during cold start after new plugs and OEM intake. Hm. Maybe the coils need to be replaced next? Maybe it is the tune?

[M2_MEDUSA]

Did you gap your plugs or leave the stock gap? Try the coils first. New Stock coils.

[ApertureF30]

Originally Posted by M2_MEDUSA

Did you gap your plugs or leave the stock gap? Try the coils first. New Stock coils.

The NGK plugs are at OEM gap. The next step is indeed new OEM coils. It is probably time for them anyway, as I'm around 45k miles. I was interested in a OTS+ Pro Tune from Jordan-Tuned, but as far as I can understand it, that is essentially a stage 1 tune. I understand that he doesn't want to do stage 2 tunes because of catless downpipes and emissions regulations tightening everywhere. I am running the AA catted downpipe, but I'm not certain I'd see any improvement going with the Jordan-Tuned tune than with the BM3 OTS stage 2 tune. All this to say, yes, coils next.

[ApertureF30]

I hope this is the final update to this post: I replaced the spark plugs with NGKs (OEM gap) and the coils with new, OEM parts. After doing so, I still would have rough starts and misfire CELs shortly after starting the car. I recently re-flashed to a Jordan Tuned OTS+ Pro Tune (93 octane), and so far cold starts are much smoother. I haven't thrown a misfire CEL yet, and I'm hoping it stays that way. I will update this again if the problem persists. Thanks everyone for the feedback.

[F36_Paul]

So as expected, BM3 tune is garbage on b46/b48s.

[HeartbreakerF80]

You’re a saint for continuing to update us fr. Hope you got everything sorted.

[ApertureF30]

Final update to the entire saga:

As a recap, BM3 stage 1 tune ran perfectly fine with an AWE axel-back exhaust and Dinan CF intake. BM3 stage 2 with a catted AA downpipe caused all sorts of issues from rough idle at cold starts to misfires. I replaced the plugs with NGKs, re-installed the OEM intake, and replaced the coils with OEM parts. Issues persisted, so I did a Jordan Tuned OTS+ tune, which solved the issues. However, I wanted the power from the stage 2 tune, so I decided to try going back to BM3. This time, however, I selected OEM for the catalytic heating (cold start) option, and the car is perfectly happy. I have not had a rough start or misfire since retuning about 2 months ago. I feel more than a little dense for not trying more "OEM" options in the BM3 tune first, but hey, new plugs and coils aren't a terrible thing for a 2018 with 45xxx miles, especially when tuned. Thanks for all the support and suggestions. Now that I'm happy with the go-fast bits, time for wheels, tires, suspension, and some brake mods. It is going to be an expensive summer. And yes, I know that I'm modding backwards...

[jtalweezy]

Stage 2 BM3 OTS requires a full turbo back exhaust. It could be that cat was causing the issue. However, the oem cat heat mode makes sense. The turbo does spool slower with a cat. I am at 84700 miles with bm3 stage 2 installed at 34k. no issues. all spark plugs gapped to .022-.023. Still running OEM coils. catless.

[LA430]

Also some food for thought. Don’t know if it applies here.

I had the same issue with MG Flasher stage 2, but I had cold start disabled on start up roar enabled. I put both of those back to stock and have had no issues on cold start for months.

[HeartbreakerF80]

Originally Posted by jtalweezy

Stage 2 BM3 OTS requires a full turbo back exhaust. It could be that cat was causing the issue. However, the oem cat heat mode makes sense. The turbo does spool slower with a cat. I am at 84700 miles with bm3 stage 2 installed at 34k. no issues. all spark plugs gapped to .022-.023. Still running OEM coils. catless.

50k miles tuned no issues at all??

[ApertureF30]

Originally Posted by jtalweezy

Stage 2 BM3 OTS requires a full turbo back exhaust. It could be that cat was causing the issue. However, the oem cat heat mode makes sense. The turbo does spool slower with a cat. I am at 84700 miles with bm3 stage 2 installed at 34k. no issues. all spark plugs gapped to .022-.023. Still running OEM coils. catless.

I would go to a cat-less set up, but I live in VA and we have emissions testing here. Besides, I feel a bit compelled to be polite to Mr. Polar Bear. Actually, I wanted to run the full AWE cat-back exhaust on my car, but I had to settle for the axel-back and the catted AA downpipe. Car has been running great for the last 5K miles since I made the tuning changes (i.g., back to the OEM "cold start" settings).