Datalog Lambda and injector learning bits problem - Log inside


New Member
Aug 12, 2021
Hi community ;-) I have a problem with my car and working on a fix for a year now without success. I hope somebody can help.

Car: 335i, N54, 2008, MSD81 - HW: IJE0S, Current SW: 7628530, MT, 75kmiles.
Mods: FBO: Intercooler + chargepipe + catless dp's + inlets + stage 2 lpfp + FTP PCV valve + 335is Clutch + Mr.5 Intake + K&N filter in stock air filter box
SW: MHD Stage2+ 102oct v9.0.

Not all learning bits are set for lambda / injectors in Inpa. All readiness bits are set except catalytic converter (due to catless DP). No fault codes besides shadow codes for catalytic converter and fuel pump plausability (2AAF, due to stage 2 lpfp)
(by the way the not set learning bits / corrections seems to be the reason why exhaust burble in MHD is not working in my case).

Corrections for uneveness are not set for example and some for lambda. It was difficult (but not impossible) to pass the German emissions test because the car was not able to hold lambda correctly. The allowed window is 0.97...1,03 @ steady >=2500rpm for 15 or 20s. After the 15th try it was sucessfull (nice guy at test station by the way).
Symptoms: Slight uneveness at idle. Cold / warm doesn't matter. That's it. Sometimes the engine is buttersmooth but mostly it's more like a 4cyl. engine at idle. Fuel consumption is normal. Normal startup. No misfire, nothing, full power from deep down low to top.

What I have done already:
I payed for a proper analysis with INPA.
Result: In his opinion it's SW related (due to Tuning / MHD what I don't want to believe).

OBD Diagnostic:
All sensors I'm able to check with Inpa give reasonable and logical values.
Furthermore I have the MHD Monitor license, logs attached for WOT and idle, see below. I can provide more.

Fuel / Exhaust:
All Injectors changed to Index 12 (+coding and delete adaptions for sure), all 4 lambdas are new (Bosch), checked the exhaust for air tightness (exhaust manifold until midpipe)

Spark plugs are new (NGK one step colder), new coils

New vanos valves, new crankshaft sensor, checked intake manifold for leaks with smoke test, Compression checked, crankcase underpressure at idle seems okay (no big change of lambda integrators when open oil fill. cap - means most probably no bad air by opening the crankcase and system is working) it's a slight underpressure in the crankcase as it should be, I manual cleaned my intake valves. Checked the DMFW according to a LUK Instruction during clutch install. New engine belt, tensioner and pulleys, when doing this tested the alternator clutch as well.

Flashed back to stock (full uninstall MHD but remain on latest released SW for my DME) - no change - installed a self made DP fix during this time to avoid CEL which was working and set catalyst converter readiness but didn't solved the issue

Other uncommon behaviour:
Sometimes LPFP pressure jump to 8x psi after WOT and stays there with 74%pwm at idle (normally it's ~60% and 72psi) but that seems to be common (EKPM3 from factory by the way).
Slight turbo siren noise when engine is cold. When I installed the Inlets I checked both Turbos. Both looks good. No oil, low radial / axial play, no wastegate rattle but it let me think there is maybe a leak in the exhaust system which causes the sound? No smoke or uncommon oil consumption. White smoke only when it's cold outside and this is normal as well due to condensation.
Not 100% alligned AFR's when I decelerate and both banks jump to 234,95, see logs (anyway it's just about 0,2seconds in worst case and by checking other logs from people it looks acceptable).

Next plan:
New crankcase vent hose (Inlet to crankcase ventilation), maybe clean vanos filter even Inpa shows very low jittering there and Vanos seems to be okay. Double check air tightness in exhaust system, maybe a new valve cover, maybe downgrade factory SW with WinKFP, maybe check main Cat with boroscope, deeply study of msd80 Funktionsrahmen to become aware what needs to be ensured to set the not setted status bits.

Can it be SW related but not because of the tuning but because of a buggy release from BMW? I checked SP daten and it's the latest SW for my car flashed / MHD did this for me. I'm running out of ideas. Maybe some of you know a specialist for analysis or have a good idea. To be honest I don't think my next steps will give the solution but I don't have better way. Could the 102oct. fuel a reason?
LOG: See in 4th gear: a slight overboosting due to Inlets, LTFT under WOT: jumps and goes to zero, seems uncommon?

Link to logs:
WOT third gear, small pause, WOT fourth gear:

Idle 1 - lambda was not regulating that good:

Idle 2 - a few minutes later lambda was regulating better:

Sorry for the long post. PM me for a potatoe ;-)
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