Fuel cut issue? Am i the only one experiencing this ?

[Cptnslo]

Has anyone experienced fuel cut when their car is below 1/4 tank? I've been trying to track this issue and initially I thought my MAP sensor was acting up but today i realized that it seems to get worse when the gas level is 1/4 tank or less. Under mild to semi wot conditions the car will accelerate then fall on its face then immediately pick back up and repeat. Would be consistent with the ecu cutting boost and timing.Since the supra is such a new platform I havent found anything about it. However I searched under regular b58 stuff and some people with other BMW in general (not even necessarily B58 platforms) have reported pickup issues when below 1/4 tank.
I'll be running some logs once my MHD comes in but I was wondering if anyone else experiences this.

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[handsoffsam]

Has anyone experienced fuel cut when their car is below 1/4 tank? I've been trying to track this issue and initially I thought my MAP sensor was acting up but today i realized that it seems to get worse when the gas level is 1/4 tank or less. Under mild to semi wot conditions the car will accelerate then fall on its face then immediately pick back up and repeat. Would be consistent with the ecu cutting boost and timing.Since the supra is such a new platform I havent found anything about it. However I searched under regular b58 stuff and some people with other BMW in general (not even necessarily B58 platforms) have reported pickup issues when below 1/4 tank.
I'll be running some logs once my MHD comes in but I was wondering if anyone else experiences this.

Definitely run into this on the track but can’t comment on street.

 

[gcmak]

On track yes but it's usually trying to power out of a corner or during a long sweeper while on throttle.

 

[OneTimeAccount]

Happened to me once on track as soon as I hit a straightaway after a long right-hand sweeper. It is a common issue. Hasn’t happened to me on the street yet, though.

 

[Cptnslo]

Happened to me once on track as soon as I hit a straightaway after a long right-hand sweeper. It is a common issue. Hasn’t happened to me on the street yet, though.

Was this because of the pickup or did you ever find the issue and do you remember what your fuel level was?

 

[Cptnslo]

Definitely run into this on the track but can’t comment on street.

What was your fuel level?

 

[underdonk]

Does it do it with traction control/vehicle stability control completely off (long press of the button)?

 

[Cptnslo]

Does it do it with traction control/vehicle stability control completely off (long press of the button)?

Not seemingly, i typically leave traction on though even in sport mode since im driving around town, why do you ask?
Also currently my launch control will not activate.

 

[underdonk]

Not seemingly, i typically leave traction on though even in sport mode since im driving around town, why do you ask?
Also currently my launch control will not activate.

It could be what you're feeling. IME, it's tough to tell the difference between the two. Just something to rule out... maybe drive around with it off and see if you can reproduce the problem?

What steps are you taking to use launch control?

 

[Cptnslo]

It could be what you're feeling. IME, it's tough to tell the difference between the two. Just something to rule out... maybe drive around with it off and see if you can reproduce the problem?

What steps are you taking to use launch control?

I'll give it a shot! Its dead stop, sport mode and traction button once and then brake all the way down and foot on the gas slowly raising it to 2kish rpm. I've tried both slowly raising it and foot down on the gas also and it goes to 2300ish and holds but I dont get the little flag that you're supposed to get.

 

[underdonk]

I'll give it a shot! Its dead stop, sport mode and traction button once and then brake all the way down and foot on the gas slowly raising it to 2kish rpm. I've tried both slowly raising it and foot down on the gas also and it goes to 2300ish and holds but I dont get the little flag that you're supposed to get.

With this procedure, left foot (hard) on the brake and putting your right foot (hard) on the gas and all the way to the floor past the detent, does it maintain 2300ish RPMs or rev out? FWIW, I've never noticed a little flag on the dash anywhere, but I'm also not looking for it.

 

[Cptnslo]

With this procedure, left foot (hard) on the brake and putting your right foot (hard) on the gas and all the way to the floor past the detent, does it maintain 2300ish RPMs or rev out? FWIW, I've never noticed a little flag on the dash anywhere, but I'm also not looking for it.

It holds and maintains them thats why I was confused. I would expect it to rev out so I wasnt sure if it was changed on later models. My ecu is dated 2019 and I wasnt sure if the flag was added later in 2020 model year. If you get a chance and can check yours id appreciate it greatly!
I was looking at yt videos and they showed the flag so I was like hmmm maybe its not functioning but if the holding is the launch control then I won't be as concerned.

 

[underdonk]

It holds and maintains them thats why I was confused. I would expect it to rev out so I wasnt sure if it was changed on later models. My ecu is dated 2019 and I wasnt sure if the flag was added later in 2020 model year. If you get a chance and can check yours id appreciate it greatly!
I was looking at yt videos and they showed the flag so I was like hmmm maybe its not functioning but if the holding is the launch control then I won't be as concerned.

Interesting re: the flag! I'll definitely check tomorrow and let you know. If it's maintaining relatively low RPMs with your foot buried it should be working. All you have to do is quickly release the brake and the launch control will engage. I don't think it's the quickest way to launch the car, regardless, but I have nothing to back that up besides the butt-launch-o-meter. Traction control and VSC seem to be very aggressive when launch control is used.

 

[OneTimeAccount]

Was this because of the pickup or did you ever find the issue and do you remember what your fuel level was?

Fuel level was one or two bars. Car went into limp mode and it gave me a power reduction warning, but said continue driving. Pulled into the paddock, restarted my car and all was fine. Scanned for codes and nothing showed up.

Reached out to Jackie Ding who tracks a Supra a ton and told him about the error without any fault codes and he asked if it happened on or after a long right hand sweeper… first thing he said was fuel starvation.

 

[Cptnslo]

Interesting re: the flag! I'll definitely check tomorrow and let you know. If it's maintaining relatively low RPMs with your foot buried it should be working. All you have to do is quickly release the brake and the launch control will engage. I don't think it's the quickest way to launch the car, regardless, but I have nothing to back that up besides the butt-launch-o-meter. Traction control and VSC seem to be very aggressive when launch control is used.

I did some draggy testing and yeah the the launch control was slower then me leaving traction on haha and monitoring my own pedal modulation

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