MT revs upwards when hard driving in between shifts

[zpower86]

In addition to what has been mentioned, there is also a clutch switch very close to the engagement point which changes the throttle mapping.

EDIT: since my comment is a separate topic, I have started a new thread posted here:

https://www.supramkv.com/threads/mt...clutch-is-disengaged-clutch-pressed-in.23081/

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[swrdply400mrelay]

In addition to what has been mentioned, there is also a clutch switch very close to the engagement point which changes the throttle mapping. Rev matching can be ON or OFF.

You can test it in neutral. Press clutch in and rev and hold 2k rpm, then let clutch out. Your RPMs will shoot up dramatically! The inverse happens if you start with the clutch out.

IMO this is a design flaw that needs to be corrected. It’s repeatable 100% of the time and in any gear. Problem affects my 2024 and another 2023 MT I have access to.

This problem is likely the reason why so many people have difficulty shifting smoothly. It also makes launching the MT consistently very difficult.

Just tried this, but I'm not sure what you mean by clutch switch?

Hoping there's a software fix for this.

 

[WSUPRA]

Was driving my 6MT all weekend on a road trip and was able to replicate this issue, and found the fix.

TLDR; this happens when you slightly bump into the gate for a lower gear when upshifting.

Try to be more accurate with your shifter hand and this won’t happen.

 

[BMWAF]

So I tried to invoke the "rev-matching on upshift" and well.. no offense, but if you are experiencing this feature or heaven forbid, using/relying on it, you are simply not driving a manual properly.

Are you lot for real?

EDIT: Wrong thread.. but I think both threads are talking about the same thing.

 

[Canfilm]

I haven't experienced this problem but have a love/hate relationship with the transmission. I did recently turn off the rev match function however to see if it would improve the 1-2 shifts: No real change after a day of driving. Seems like this gearbox has a variety of little gremlins.

I'm not sure if its worth reporting the 1-2 shift issue with Toyota or not.

I just did the CDV mod, & it has made the shifts smooth like they should be.

 

[Canfilm]

I just did the CDV mod, & it has made the shifts smooth like they should be.

Same. Changed the clutch slave (CDV delete), and the car is now normal.

 

[Turbro]

Just wanted to update. This just happened to me twice today from 1st to 2nd, kind of annoying. Guess ill turn off rev match. Can we turn off rev match in normal? bimmercode or anything?

 

[ColonelAdama]

Yep did it to me this morning on my commute as well. Annoying. Made me look stupid while showing off the car to a friend last month too. ?

 

[Turbro]

Yep did it to me this morning on my commute as well. Annoying. Made me look stupid while showing off the car to a friend last month too. ?

Ya some guy was watching me leave a parking lot, and it did it. Shifted from 1st at 4k rpm and it straight up launched to redline for 2nd, then it just rode the clutch for a second as RPMs came down. Fucking stupid feature

 

[Turbro]

Update : turning off rev match doesn’t fix this issue. Very fucking stupid.

 

[djf]

Reviving this to ask if anyone’s gotten more info on it

 

[lucky phil]

Yep did it to me this morning on my commute as well. Annoying. Made me look stupid while showing off the car to a friend last month too. ?

You should be able to log this and find the reasoning with all the EFI work you've been doing surely? Or is it too random? From my understanding "rev hang" is a programmed emission reduction strategy but this sounds a bit different? No issues with this on my car for info.
Phil

 

[ColonelAdama]

You should be able to log this and find the reasoning with all the EFI work you've been doing surely? Or is it too random? From my understanding "rev hang" is a programmed emission reduction strategy but this sounds a bit different? No issues with this on my car for info.
Phil

honestly I haven't had it happen since I've been on my custom MHD map. It definitely wasn't rev hang. it was like the accel pedal went to the floor lol

knowing what I know now, it was probably the clutch-(dis)engagement logic (aka MDK) in the dme failing to cut torque (pull timing and fuel) during the gear change. A symptom of that not working as intended would absolutely be rev climb during the shift even without touching accel pedal.

 

[Goko]

It was intermittent for like the first 5k miles, but now that I’ve driven my car about 10k miles, I haven’t had the issue. I’m pretty sure I’m shifting the same, so I’m not sure what changed. I still have rev match on and only installed a clutch stop recently.

 

[BMWAF]

knowing what I know now, it was probably the clutch-(dis)engagement logic (aka MDK) in the dme failing to cut torque (pull timing and fuel) during the gear change. A symptom of that not working as intended would absolutely be rev climb during the shift even without touching accel pedal.

I think you're onto something here. My experience though, is stranger still. With rev matching off, the shifts are OK but can randomly become a bit clunky - that first to second shift is really the only one I'm complaining about. If I switch on rev matching, everything works fine for a while but after a half hour or so, the shifting becomes worse than before and very inconsistent. My working theory is that the onboard computer gets clogged up and after a while, just stops applying the logic properly.

My experience has been the same stock, with JB+ and also now MHD Stage 2.

There's also the fact that coming from a Honda box, my tolerance for poor shifting mechanisms seem to be far lower than most.

Another interesting fact is that - along with weird flashing side effects mentioned elsewhere - rev matching seems to get turned on automatically after every flash. #MHDThings.

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