[wawtor]

Hoping someone on here can help me with this. My car has been running poorly but I cannot seem to figure out why.

I am currently on stock tune hoping to throw some codes that point in the direction. I was running BM3 Stage 2 93. I have tried the 91 octane and stage 1; same results. The LTFT is fine at idle but[ATTACH]undefined[/ATTACH] seems to increase with engine rpm suggesting a MAF or fueling issue.

The MAF readings seem fine to me but then again, I may be overlooking them. I replaced the LPFP with precision raceworks stage 2 as the HPFP seems to be steady when reaching its target.

I have smoke tested the intake and Evap system and have not been able to find a leak.

Anything will help and I will attach some datalogs.

https://www.bootmod3.net/log?id=6692...350f446af069f1
https://www.bootmod3.net/log?id=6695...53e853997459e4

MODS: Active Autowerks FMIC, Active Autowerks CP, K&N drop in filter, VRSF catless dp, Precision racework stage 2 LPFP.

[wawtor]

Oil started to smoke from the back of the VC... Will be repairing this weekend and will report the outcome. Hoping this resolves the issues....

[wawtor]

Although replacing the VC entirely and replacing the turbo inlet pipe has remedied the issue quite a bit. I’m still getting LTFt spikes when under load. Gonna be replacing the MAF with fingers crossed

[wawtor]

After changing LPFP, Charge Pipe, Boost pipe, diverter valve, ALL gaskets regarding anything intake related, MAF, MAP(s), valve cover, OFHG... Problem still persists... all connections are airtight.

Thinking maybe HPFP? Injectors?

LTFT shoot up under partial load mainly at highway speeds...

Need help!

[Coupsoup]

Took a quick peak at the data logs. What I noticed on the stock tune is that the LTFT was nearly a mirror image of the STFT. The MAF data is nearly flat on the stock log as well.

Remember when looking at fuel trims you need to add LTFT to STFT to get total trim.

That being said on the tuned logs the LTFT typically peaked right after STFT and shot up as STFT dropped. This is because STFT is typically capped at around 20% but total trim can go upto 30% depending on manufacturer.

The load % dont seem to make sense on the first log but vehicle speed is zero so I'm going to assume these trims get much worse when you're actually driving it.

The engine is definitely leaning out, especially at high rpm. Your lambda for some of those throttle blips was as high as 17.7.

I'd say, since these readings are unloaded and the fuel pressure readings are tracking with the desired, that it is much more likely you've got an air leak or a bad MAF. I see you replaced it but I've installed plenty of off brand MAFs that are bad, so if it wasn't BMW part it's not out of the equation yet.

You can do an easy MAF analysis by logging IAT, RPM, MAF and doing 3 wide open throttle pulls. Put it in 2nd or 3rd gear, floor it.

https://atgtraining.com/atg-volumetr...cy-calculator/

At peak rpm on each of the pulls (the rpm will vary the important part is being WOT) input the values into the calculator.

Anything under 90% or over 100% indicates a problem.

If you're sure the exhaust isnt plugged and the intake isn't leaking this means a bad MAF. If the readings are between 90-100% and your sure the exhaust and intake aren't the issue you're back to looking at fuel.

But at a glance I suspect an air leak. It seems you've changed all the parts so we're going to assume the work is good at try and look at things you haven't considered.

Unplug the purge valve and remove the outlet hose. Check for the presence of vacuum flow with the engine running. If there is vacuum present the purge valve is stuck open.

But really we need logs from a drive. What the car is doing at idle has almost nothing to do with how it drives.

Dont worry about knock sensors or cylinder specific ignition timing. Plot the trims, the temps, the load % and the pressures. If you can get injector on time grab that too.

I do a little diagnostic tech line work and I'm a full time tech but I am relatively new to the brand so take this with a grain of salt.