[ztkm340]

Hello all,

To keep this short. I went to the track recently, this is the second time since I owned the 2024 M340i xDrive w/ ZTK package. There's nothing done to it, besides oil change and filter w/ 2700 miles.

The first 2 sessions of the day it was doing great, on the 3rd coming out of a fast sweeper onto the pit straight. I thought I hit rev-limiter (manual shifting) and bang, the Gear light on and Drivetrain Malfunction, I already missed the pit-entry so had to limp through the whole lap.

Came to rest, restarted the car, the light is gone. I check the Oil level and everything looks great. Go back out there for another session, I did maybe 3-4 clean laps, before this creeped up on me again and in the same exact place. I thought that maybe I bounced off the limiter again. I quickly drove to the pits to restart the car. Great, light is gone, now I'm thinking some sensor is getting triggered.

Same thing, same place but this time I made sure I would shift-up before getting into red-line and as I hit the shifter up. Coming out of the sweeping right-hander onto the pit-straight and bam, again. I decided to call it a day. After restart all the lights are gone, car drives great. Drove back home without a single issue, checked oil and still showing at Max.

I have a service appointment scheduled for this, but did anyone experience something similar or know what might be happening so I'm prepared to talk to the dealer?

[chrispy28_xd]

What was your fuel level? Our cars get fuel starvation at ~50%, and in my experience, only at right handers. I start every session at 75% fuel at minimum to combat this.

Edit: I've actually experienced it on a left hander (Laguna Seca T11)

[ztkm340]

Originally Posted by chrispy28_xd

What was your fuel level? Our cars get fuel starvation at ~50%, and in my experience, only at right handers. I start every session at 75% fuel at minimum to combat this.

Really? That might be why as I started getting these from 3rd session and the previous 2 went clean. I'm not sure how to actually check fuel level as I only see the computerized display with what I think is a prediction of range. But when it was happening it was showing 169 miles range so probably around 50%. But it does make sense, as then after each lap on the same sweeping turn, it was going into limp mode. I thought that maybe it has to do with bad fuel, but then again, why would it be fine for the first 2 sessions. I was thinking on topping it off and going out there again but was afraid of any potential damage.

Is this a known issue? Any solutions to this?

[chrispy28_xd]

The computerized display is accurate in my experience. I usually don't do full sessions because of various reasons, but I typically go through 1/4 tank per session. So assuming you start the day at 100% fuel, just top up after every 2 sessions.

And yes, this is a well known issue. You can do a google search of "a90 supra track fuel starvation", and you'll see it well documented. All the solutions are pretty much race car level, so I recommend just keeping it topped off every 2 sessions.

[ztkm340]

Originally Posted by chrispy28_xd

The computerized display is accurate in my experience. I usually don't do full sessions because of various reasons, but I typically go through 1/4 tank per session. So assuming you start the day at 100% fuel, just top up after every 2 sessions.

And yes, this is a well known issue. You can do a google search of "a90 supra track fuel starvation", and you'll see it well documented. All the solutions are pretty much race car level, so I recommend just keeping it topped off every 2 sessions.

Well then that explains it. You think I should still take it to the dealer to have them check it out? Do you know if anyone complained about this to BMW, seems not optimal if you get starvation at 50% or lower. I've tracked few different cars before M340 and they definitely drained the tank more before complaining about fuel-pressure drop or misfires.

[chrispy28_xd]

Can't really expect BMW to fix something that only happens during high performance driving. FWIW other sporty cars also have this issue (e.g. Giulia). I say skip the dealer and just keep your fuel topped up next time.

[prostcfc]

Interesting. I'm a 2020 and haven't had this issue, though I'll keep it in mind. I also use ~1/4 tank per session, and I let it get down to 1/4 before I refill, generally.

[ztkm340]

Originally Posted by chrispy28_xd

Can't really expect BMW to fix something that only happens during high performance driving. FWIW other sporty cars also have this issue (e.g. Giulia). I say skip the dealer and just keep your fuel topped up next time.

Cool. I cancelled it and going to go out again with a full tank see what happens, but that has to wait until October before my next track day. Thanks for the info.

[peelerec]

Originally Posted by ztkm340

Cool. I cancelled it and going to go out again with a full tank see what happens, but that has to wait until October before my next track day. Thanks for the info.

I concur with everything Chris has mentioned. In fact, I discovered the same issue at the track (Thunderhill East Turn 14) and thanks to Chris’s quick diagnosis he calmed me down and assured me to just fill up on fuel, which solved the issue. The only lingering consequence from that one incident was that my LPFP (Low pressure fuel pump) burned out. Went to the dealer (did not disclose why, where or when it happened) and it was replaced under warranty.

Here is the thread I made on this subject:
https://g20.bimmerpost.com/forums/sh....php?t=2045656

[ztkm340]

Thanks for all the great info. Wish I popped on here during the track day. I'm just a bit bummed that 50% of tank is not enough to maintain constant pressure. Did they save on baffles? Does anyone have an actual link that talks about the underlaying problem?

[ztkm340]

I saw the A90 Supra group talking about Holley HydraMat as being a quick fix. Now we just need someone brave to try it