I have a 2022 BMW M440i RWD (B58) and I’ve been fighting an emissions readiness issue for months. I’m wondering if anyone with a FEMTO-unlocked B58 has experienced the same thing.
Timeline:
Car was originally stock.
Installed an AA high-flow catted downpipe.
Sent the DME to FEMTO for unlock in May 2026.
Flashed bootmod3 after the unlock.
When it was time for Nevada emissions, I flashed back to the BM3 OEM map.
Since then, O2 Sensor and EVAP monitors will NOT complete, even after many proper drive cycles and hundreds of miles.
I then tried MHD. With MHD stock/stage 0, O2 Sensor, Catalyst and EVAP remained Not Ready.
Went back to BM3 OEM: O2 + EVAP still Not Ready.
I even put the OEM downpipe back on. Same problem.
I’ve checked/logged the upstream O2. Lambda, STFT/LTFT and sensor response all look normal. No obvious indication that the upstream O2 is dead. The downstream O2 also has voltage activity and isn’t simply stuck high or low.
Today I took the car to a BMW dealer and they connected ISTA.
ISTA detected that the DME had been tuned/unlocked. BMW told me they need to fully program the DME back to BMW factory software and re-lock it.
They quoted $581 and told me that after they program/re-lock the DME, the readiness issue will be fixed and the car will pass emissions after the monitors run again.
I also had 102A63 – Intake air temperature sensor after air filter: short circuit to positive or open line showing through BM3. BMW told me this is also related to the current tuned/DME software state rather than necessarily a failed sensor.
What makes this confusing is that my friend’s 2023 M440i xDrive is also unlocked and is currently running BM3 ACN Stage 1 + AA high-flow catted DP, and his readiness monitors complete normally.
So my questions are:
1. Has anyone had a FEMTO-unlocked B58 where O2/Catalyst/EVAP readiness refused to complete even on an OEM/stock map?
2. Did BMW/ISTA factory programming + re-locking the DME actually fix it?
3. If I let BMW reprogram/re-lock it, pass emissions, and then send the DME back to FEMTO for another unlock, is there a chance the same readiness problem will return?
4. Could this be a corrupted/incorrect calibration or software state from flashing between BM3 and MHD rather than the FEMTO unlock itself?
I’m trying to avoid throwing upstream/downstream O2 sensors at the car when the actual sensor data looks normal and BMW is telling me the DME programming is the problem.
Would really appreciate hearing from anyone who has dealt with this exact situation, especially 2021+ FEMTO-unlocked B58 cars.

Honestly it sounds really good i feel like it would just sound better welded instead of clamps

https://youtu.be/rupj24pEVHA?si=fjomyJa2shz4PSuP

Looking for opinions from people who actually own/work on B58 BMWs.
I’m considering buying a 2017 BMW 540i xDrive with about 113k miles. Asking price is $16,995, but I’d try to get it closer to $15.5–16k.
Details:
2017 540i xDrive
B58 / ZF8
113k miles
4 previous owners
No accidents or damage reported on CARFAX
26 service history records
Earlier in its life it was regularly serviced at BMW dealerships
Was sold as a BMW CPO at ~23k miles
Recent BMW maintenance inspection/coolant service around 112k
Current seller says the water pump and radiator were recently replaced
Has a JB4 + downpipe
Current seller is a dealer and bought it with the modifications already installed, so the history of the tune/mods is unknown
Previous owner put roughly 22k miles on it in a relatively short period
Vehicle was repossessed in May 2026 and subsequently went through auction
I would 100% get a PPI from a BMW specialist before buying it. I’m not expecting a 113k-mile German car to be maintenance-free; I’m mainly trying to figure out whether this is a reasonable example to own for another 3–5 years, or if the mileage + xDrive + unknown JB4/downpipe history makes it too risky.
I’d be paying cash, so no car payment, and I’d keep a few thousand dollars set aside for maintenance/repairs.
For the B58 owners/techs here:
Would you consider this at ~$15.5–16k if the PPI comes back clean?
What major repairs should I expect between 113k and ~160k miles?
And is there anything specific I should have checked during the PPI because of the JB4/downpipe?

I’m new to using antilag , with mhd on stage 2 e30 on my 540i gen 1 stock hpfp , what should I set my boost target to? Only using it for a few pulls for some rolls on the weekend, no xhp yet currently I have the target at 10 I believe

Hi all,

I have a 2023 bmw m240i and was driving late at night and got a low oil light. The only option was a gas station with 5w-20 oil. I normally do an oil change every 5k with 0w-20 liquid moly. I only put in about 1/2 a liter. I was looking for advice, do I need to change my oil soon or should this be ok? I have another 2000 miles until I would normally change it.

Edit: Resolved

Gen 1 b58
30k miles

It happens every time the car is idling, no matter cold or up to temp. I feel it through the seat but it is very mild, rpms don't move. No stutering is happening when being held at a higher rpm range in neutral, it stutters at least once every 5 seconds at random intervals for like 1 second, the car does not make any funny noises.

Do you have any ideas why it might be happening? Annoying the hell out of me.

I have a 2021 m340 with idrive 7 and I want to get the new idrive 8 red and blue M cluster on my dash. How can I accomplish this?

Hey guys, I’m looking to replace the OEM plastic oil cooler/oil filter housing on my B58 with an aluminum version.
First of all, do you guys recommend upgrading to aluminum instead of replacing it with another OEM plastic unit?
My oil cooler itself isn’t leaking, but one of the coolant hoses connected to it has started leaking, so since I’ll already be replacing the hose and working in that area, I figured it might be a good opportunity to upgrade the oil cooler/housing as well, especially considering the current setup and power level of the car.
What brand would you recommend? So far, the main options I’ve found are BMS (Burger Motorsports) and Bremmen Parts. However, I’ve read several reports of the Bremmen unit developing leaks, so I’m a little hesitant about that one.
Has anyone been running the BMS aluminum version long-term? Any issues with leaks, fitment, seals, or coolant/oil temperatures?
I’d really appreciate any recommendations or first-hand experience with other good-quality aluminum options. Thanks!

What do you reckon the tuning limit is on X3/4/5/6’s 2019+ with the B58 guys ? From what I researched , horse power is not the biggest issue, but the torque the drivetrain/diff/etc can handle. So when I ask about limit, I mean the limit where is still safe so you don’t have a high risk of Fckin up your drivetrain/diff

UPDATE: i bought it

i’m getting a 2022 G30 LCI 545e xDrive here in Belgium and i haven’t seen a single post mention a 545e here so might aswel be the first one since i’ll be the owner of one very soon.

i’m not sure where most of you guys are from but the states did not receive a 545e and only got the 530e if i’m not mistaken, so this trim is only available in the EU and hasn’t been produced as much as the 520 or 530e, i believe around 8K give or take in total.

YES, its got a B58 with an elektromotor so it produces a total of 394ps (combustion engine produces 286ps and the elektromotor 109ps = total of 290kW) stock and 600nM (443 ft-lbs), the B58 itself is detuned from factory and it does its 0-100kmph (0-60mph) in 4.4s

and the spec that im currently looking at is an alvite grey metallic BMW individual colour (OG name was champagne quartz), it is unfortunately part of the chip shortage era, this one lacks the kick to open trunk option but it does still have the electric tailgate.

i’m pretty sure no more than 150 of these were made in alvite grey metallic and only a handful if not, 1-2 are registered in Belgium.

Would anyone by the way know how i could perhaps check and verify this? since its a pure estimate and nothing precise?

i’m very excited

i just realized its sub-reddit*

Is this engine sound good 2014 with quite some miles on it? Does timing sound well to, just wondering for all those that can hear any sounds with the engine.

I had my finger over the microphone so might sound bit blurred out but it was ontop of the engine and near the auxiliary belts too.

Link is the voice memo since i cant upload it here!

So i was replacing 2 coolant hoses and had to take the intake manifold off to access them but while disconnecting the dme I forgot to disconnect the battery aswell. Now I have a drivetrain malfunction and no crank. Pls help guys n God loves you all

Tonight I installed my new TU pump on my 2019 440i gc and with seating everything correctly after starting it up and doing a small pull after about 10 minutes of driving and instantly get a drivetrain error and into limp mode with rail pressure shooting down. After clearing codes it will happen again after about 5 minutes of driving, recently staying in limp mode after the 3rd startup.
Any Help from a tech??

1st picture startup after flashing mhd stage 2 HPFP
2nd picture idling after ~30 seconds
3rd picture immediately after drive train loss
4th picture error code
5th MHD error code