Tacoma - OVTUNE - VFTUNER - Update Info and Original Development

I was monitoring accelerator position and downshifts yesterday and would consistently downshift from 6 to 5 around 24-25%, highway 60-70 mph, 87 Performance tune, and with ECT on.

 

in what gear?
at what speed?
at what RPM?

FYI, for all the people who think they have "dead pedal" issues. A few things to understand:
currently, transmission shift is controlled by accelerator angle
if you're at ...1800 RPM for example.. the difference in how much power you get at 40% throttle and 80% throttle is 0 (as an example).
Opening the throttle more on this engine does not always = more power. Entirely RPM dependent.

Actual vs effective angle.

There is not a single shift point that requires 85% accelerator angle to downshift.

 

I

I was on 91 with GL, went to accelerate on an on ramp, had etc on, pressed gas and it would not downshift, reached over and turned off etc, and it immediately downshifted and took off.

Didn't ever have an issue with ETC turned off.

 

You know when ECT is on it's Gearlocked right

 

I cant say with certainty what gear it was in possibly 5th. I was going 80mph (but i have had this at lower speeds). I wil press the peddle and rpms will not raise and speed will not increase. I push the peddle very slowly to what feels like 85% and if i push any further it will down shift and rpms jump all the way up and send the truck flying down the road. I would need to hook up to pc while driving to get exact specifics.

Edit rpms about 2k

 

Were you in S or D when you had ECT on? I believe Mat said if you have ECT on in D it will not downshift.

 

I found that if you press the accelerator slowly it doesn’t react but if you press it quickly it reacts

 

If you push the gas very slowly this can happen, but it's not really tune related it's more related how the ECU is calculating requested torque. But to get it to do this you have to purposely be pushing the accelerator in very slowly. That's just the request logic, not modified in the tune.

 

This makes total sense based with what I’m experiencing

 

Get OBD Fusion and stop guessing.

 

Yes - and it's an absolute deal breaker for me. Cruising at 85 mph (Texas!!) just over 2000 RPM - that's great but of course the engine won't make a lot of power. Even on moderate hills, I have to start pushing in the throttle, which initially increases RPMs to 2500. That's not enough tough to keep the speed at 85 mph on the slight incline, so need to push on the pedal more and more (and yes, it feels like 85 % or so) before the engine will downshift...but not just one gear, no...I end up at almost 6K RPM and the truck jerks forward at that point. As soon as I let the petal out, back to 2K RPM we go and the game repeats. At no point was I able to get to an RPM number BETWEEN 2500 and 6000...

Maybe 93 Octane gas would help..but I'm going to flash to 87 base for now.

Bernie

 

The stock ECUs method for controlling shifts is not perfect. Using torque request / driver demand, if you do something outside the normal bounds (for example increasing gas pedal angle at a slow steady rate) request torque will not increase, no shift will occur. You can make stock tune do it as well.

Sometime later this year we'll have OUR own scheme for how shifts are controlled, via patching several sections of code and the corresponding RAM calls for them. Until then we are still limited to tuned TCU with stock logic. I don't intend to fight with this transmission forever though. Simply put, depending on your mods, the shift pattern will need modification for your truck.

 

So SOON?

 

Well...it's not as much of an issue with the standard Toyota tune. In fact, with 87 performance I much prefer cruise control - I'd rather have higher RPMs then encountering the above behavior.

 

The shift points between the 87, 91, 93 performance tunes are identical. However calculated torque is not, which is a part of how shifts are controlled. There is only so much that we can do.

 

What tune are you on?

 

Good point, my bad. I think I was in D, but I don't recall. I'm on 91 base now.

 

87 Performance...

 

Same. When I turn on ECT, downshifts at around 24% accelerator. With ECT off, will downshift around 40% accelerator.

 

So when in Gear Lock, the truck won’t down shift for you right? But does it give you the option to shift into the higher gears when you want? I’m experiencing when trying to shift into 5th and 6th. It wants to wait until I’m at about 2200 rpms to shift. I’m I doing something wrong? On 93 GL