MHD- Constant Codes + cold start stalling

[MeAndMyMR2]

Good day everyone,

I am rather new to the forums but not to BMW issues so i thank you for your time!

I have a 2011 135i 6sp convertible with the following mods and issues.
VRSF catless DP, 5" FMIC, and CP
Mishimoto oil catch can
MHD stage 1+/2 flash tune
new bosch oem plugs gapped.
new map sensor

2BC0 - Mixture Control Fuel Air mixture too lean
2BF4 - Rail Pressure sensor plausibility: Pressure too high before engine start.
2C42 - Mixture control multiple fault

These codes are followed by the occasional stalling during a cold start or at red lights (unless i raise idle in MHD). These codes started after modifications obviously but from my research the mods i have installed shouldn't really cause any issues.

I currently am leaning towards O2 sensors or some sort of fueling issue. Stage 2 only shows max 11psi tapering down to 8-9 during WOT 3rd gear pulls. Timing corrections are semi-rare at 2-5 degrees on one or two cylinders. IAT is generally within 20 degrees of ambient temp. No misfires recorded or felt.

I am looking to install Pure S2 turbo, upgraded fuel pumps, PRW coil packs, NGK one step colder plugs, and replace the diverter valve if needed. Maybe Meth oneday but would like to sort the lean/mixture issues first.

Thank you in advanced for any help!

[iminhell1]

Why new MAP sensor?

I really doubt it's an O2 sensor. Odds are far higher it's due to the parts you just put on.
Boot leaking at the intercooler would be my bet as to the boost not being on par.

The fuel stuff sounds like the rail sensor took a dive. But that seems like really odd coincidence. More likely something in the tune not being correct.

[MeAndMyMR2]

Map sensor was replaced just as precautionary measures as well as an older code i got when the car was first purchased. The post cat o2 is new because the original is stuck in the cat. When i went to vrsf catless dp i installed a new post cat, and today installing a new precat sensor. The originals will remain in the OEM Catted DP.

I was thinking the fuel pressure sensor as well as some of the numbers were wonky however it seems to be working. 2000-2200psi cold start, tapering down to about 7xx at warm idle. Fluctuating 1200-1800 under medium load. logs can be provided if needed.

MHD Suggested going to stage 0 and retesting everything which is fair, however if i dont get the same results does that mean i need a different tune/company? When i do the Pure Stage 2 turbo and supporting mods i will be getting a custom tune so that should help.

[iminhell1]

Get a good running car before you modify. That's rule #1.
Rule #2 is step back. If there is a problem after a modification, take the mod off, or go back to stock tune. Never beat on a malfunctioning car, if you value it.


Replacing a MAP is not a precaution. And there are only about 3 codes I can think of that would say for sure a MAP is dead. Anything else would point to a wiring issue or a vacuum/boost leak.

In my case, I can't log with MHD from key turn through startup. If you can, do a log like that. See what LPFP and HPFP are doing. If it's kicking a code it's saying there's a problem directly with the fuel system. Not a MAP, not an O2, not anything else. LPFP sensor, HPFP sensor and associated.

[MeAndMyMR2]

As mentioned the car was running fine and does continue to run fine now after the cold start. She pulls strong with no CEL. I just want to eliminate the aforementioned codes. I will check the LPFP and HPFP during startup this weekend. The MAP was bad originally that's why i replaced it. I have tripled checked all intercooler piping but i have my doubts with the seal on the vrsf charge pipe where it connects to the intake manifold/throttle body. The problem is that my oem charge pipe is damaged and will not seal at all (hence why it was replaced).
You dont think that the o2 sensor is what tells the car its leaning out? could it just be a wiring issue? how could i check? resistance or something between point A and B?

2BC0 - Mixture Control Fuel Air mixture too lean
2BF4 - Rail Pressure sensor plausibility: Pressure too high before engine start.
2C42 - Mixture control multiple fault

These codes to me say either fueling, dme, or o2 sensor. However i am not an expert. I can put the cat back in once it warms or for my next inspection. I will let you know how stage 0 runs and log cold start on MHD.

[iminhell1]

I have no occurrence data with the codes. Did the 2bc0 and 2bf4 happen at the same time? Where they minutes apart? Etc.
You'll need to find that out. Could be all happened at once and are due to 1 faulty part. Or could happen at varying times and be multiple parts failing. A log really isn't going to tell you here I feel. This will come down to component testing; which the BMW service software can do (ISTA-D).

[MeAndMyMR2]

If i recall correctly they all occur at the same time. Generally at a cold start. the Mixture control multiple fault and mixture lean sometimes happened during heavy acceleration if the cold start was say above 65-70F. But lately (in NY) a cold start is 28-38 degrees and the codes show up after the rough start/stall. I turned off the cold start noise reduction and it helped alot. At this time i am leaning towards MHD tune issues. I will component test tomorrow with ISTA if the rain holds out.

[PopsnBurbles]

I had the same set of codes when I had an aftermarket intake on. I put the stock one back on and the codes disappeared. Im not sure if this is relevant to your case but I hope it leads to something for you.

[Alturiak]

Was there ever a resolution to getting these codes sorted out? Currently dealing with the same ones... would love any data on what fixed yours if possible

[MeAndMyMR2]

Car has been driving fine with the same codes since modification. Even now with no catless DP running stock OEM tune I am getting DME-2774 and 2BEA with a low idle and stalling at red lights during warm/hot days or runs.

Thinking its time to replace the Valvecover & Gasket as its getting brittle and old. Will update following the maintenance.

[houtan]

Did anyone ever figure this out?

[PerformanceEngSolutions]

Seems like fuel system thinks it’s providing more fuel than it actually is. I’d replace the the low and high fuel pressure sensors first

[ShocknAwe]

Originally Posted by houtan

Did anyone ever figure this out?

Car ok hout?

[houtan]

Originally Posted by ShocknAwe

Car ok hout?

Hey Alex. Overall, yeah. Switched over to dual 450s and full e85. She picked up a little more speed.

I have had this issue for a year or so. Thought it was my valve cover, which needed to be replaced, but the issue still happens intermittently. Most of the threads I found that post about the issue don’t post a resolution.

How is everything on your end?

[ShocknAwe]

Originally Posted by houtan

Hey Alex. Overall, yeah. Switched over to dual 450s and full e85. She picked up a little more speed.

I have had this issue for a year or so. Thought it was my valve cover, which needed to be replaced, but the issue still happens intermittently. Most of the threads I found that post about the issue don’t post a resolution.

How is everything on your end?

Have you done the regulator yet??

My N54 ate all its coolant connections today. Fun afternoon.

[iminhell1]

IIRC there was some possible connection to injectors overheating. They are filled with goo to keep them cool. Long dwell times/high amperage/large demands for long periods overtax them.

But that was a theory I recall hearing.

[houtan]

Originally Posted by ShocknAwe

Have you done the regulator yet??

My N54 ate all its coolant connections today. Fun afternoon.

Nope. I’m at 65k miles. When do those typically go out?

Oooof, I keep thinking my hoses are going to go soon too.

Originally Posted by iminhell1

IIRC there was some possible connection to injectors overheating. They are filled with goo to keep them cool. Long dwell times/high amperage/large demands for long periods overtax them.

But that was a theory I recall hearing.

Is that the same for the e series n55 injectors as well?



The issue definitely seems heat related. It usually occurs after a hard canyon run or logging session where I do a bunch of back to back pulls. Car starts stuttering on light throttle. Then if I stop and let it idle for a little it will throw misfire and other codes. Clear them and restart and drives good again.

When I log it happening at idle, stft max at +33 and the afr is in the 20s.

[iminhell1]

That I don't know. I'm N54 scum.
There was a thread discussing fuel temps, using some phenolic washers on the rail to lower fuel temp and results. I thought I might have it bookmarked but I can't find it. I also don't recall which site it was on. But there was some really good info in there.

[PerformanceEngSolutions]

Originally Posted by houtan

Is that the same for the e series n55 injectors as well?



The issue definitely seems heat related. It usually occurs after a hard canyon run or logging session where I do a bunch of back to back pulls. Car starts stuttering on light throttle. Then if I stop and let it idle for a little it will throw misfire and other codes. Clear them and restart and drives good again.

When I log it happening at idle, stft max at +33 and the afr is in the 20s.

Your injectors could be gummed up from the E85. It’s recommended to run a tank of pump gas or fuel injector cleaner every 3 to 5 tanks. When was last time you ran straight pump gas?

[ShocknAwe]

Originally Posted by houtan

Nope. I’m at 65k miles. When do those typically go out?

Oooof, I keep thinking my hoses are going to go soon too.
Is that the same for the e series n55 injectors as well?

STFT+33, afr 20

Does your HPFP have a filter?? I know N54 pumps have one which is sometimes removed to improve flow, could be gummed up in your case resulting in low pressure flow issues. Could also point to regulator or injector or cylinder leak but I'd imagine those would pop up under load.

Recently had an injector fail open, caused the opposite bank to go full lean, worth checking if it's not both banks

Worried about that it's really lean. What's the LP pressure doing during these with your dual 450s?

[houtan]

Originally Posted by iminhell1

That I don't know. I'm N54 scum.
There was a thread discussing fuel temps, using some phenolic washers on the rail to lower fuel temp and results. I thought I might have it bookmarked but I can't find it. I also don't recall which site it was on. But there was some really good info in there.

Haha. And I am early N55 which is even worse. The in between n55 that has a mix of n55 and n54 parts.

I remember that thread, I think it was on SS. Thanks.

Originally Posted by PerformanceEngSolutions

Your injectors could be gummed up from the E85. It’s recommended to run a tank of pump gas or fuel injector cleaner every 3 to 5 tanks. When was last time you ran straight pump gas?

The last time I ran pump gas was probably 8 years ago haha. Been running e50 that entire time until last month when I switched to full e85. I have used chevron fuel injectors cleaner a few times though.

Originally Posted by ShocknAwe

Does your HPFP have a filter?? I know N54 pumps have one which is sometimes removed to improve flow, could be gummed up in your case resulting in low pressure flow issues. Could also point to regulator or injector or cylinder leak but I'd imagine those would pop up under load.

Recently had an injector fail open, caused the opposite bank to go full lean, worth checking if it's not both banks

Worried about that it's really lean. What's the LP pressure doing during these with your dual 450s?

I am not sure if my pump has the filter but it is essentially the same pump the n54 has. The thing is, my logs look beautiful from 13 to 28psi which is 630whp at least. AFR is 12.0, rail pressure at 2900psi, hpfp duty cycle is around 55% (I have my pi duty cycle set so my hpfp is cruising).

Yeah the afr and stft behavior are weird when it happens but I did that to wait for a code. Clear the codes and starts up normally and logs look perfect again.

I am also running mafless and probably some other things changed but car runs fine for hours and I know others running similar set ups fine.

We don’t have lpfp sensor unfortunately. Something I can add if I switch to a reflex plus, which I may do as it would be helpful to know.

We also don’t have bank 1 and bank 2 channels. The e series n55 is a tough life!! Lol

Thanks for all the replies, keep them coming. I have some research to do.

[hotchicken]

I just did an MHD tune and was getting misfires and limp mode. Installed new plugs and I’m good to go.