Surging when stopped. Anyone else?

[sprubs]

toyota seems to generally have this figured out on their eCVTs.

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[MaverickDragon]

Has anyone with the issue used the brake hold? (Switch on the right of the lower console)
When you stop, the truck can't move until you press the skinny pedal.

 

[icegradner]

Has anyone with the issue used the brake hold? (Switch on the right of the lower console)
When you stop, the truck can't move until you press the skinny pedal.

Yeah, I use brake hold all the time, works great for this issue.

 

[HeyBales]

Has anyone with the issue used the brake hold? (Switch on the right of the lower console)
When you stop, the truck can't move until you press the skinny pedal.

Tested once - same effect - it just applies more PSI than I do on brake pedal, normally.
It doesn't change any other parameters.

 

[HeyBales]

toyota seems to generally have this figured out on their eCVTs.

I wonder if they just remove the whole (ETA) charging regen during open loop time - so no resistance in the generator motor, no need to exactly hit an RPM ratio to cancel out engine torque, with an ICE RPM that's bouncing around.
Or perhaps their open loop time is really incredibly done - not really so open with default values, and smooth engine RPM.

 

[Red Eyes - Wide Shut]

I remember the first time this happened to me. I looked in my mirror thinking someone just bumped me. Then it continued like aftershocks until it decided to stop. I realized it is this vehicle twitching Whatever this is and the justifications being made for it, it ain't right and it ain't normal. Whatever it is, the most important question should be, is this creating a situation that is causing damage or wear somewhere down the line.

 

[sprubs]

I wonder if they just remove the whole regen during open loop time - so no resistance in the generator motor, no need to exactly hit an RPM ratio to cancel out engine torque, with an ICE RPM that's bouncing around.
Or perhaps their open loop time is really incredibly done - not really so open with default values, and smooth engine RPM.

at least on the Toyota I read there is a clutch to dampen sudden torque. it's not the kind of clutch that can completely disengage or anything - it just smooths things out. the one complaint I read about some toyota eCVTs was a little "shudder" when the engine starts but I haven't found anything describing like what happens on my maverick. The clutch is mentioned in this commonly posted video:





the good news is that it's rare but to to say it's anything other than a failure or a bug or whatever you want to call it doesn't seem accurate. a poster above actually hit another vehicle because of this. fortunately no damage or injuries but what if that was a kid crossing the street in front of them???

 

[Mavster Mechanic]

I wonder if they just remove the whole regen during open loop time - so no resistance in the generator motor, no need to exactly hit an RPM ratio to cancel out engine torque, with an ICE RPM that's bouncing around.
Or perhaps their open loop time is really incredibly done - not really so open with default values, and smooth engine RPM.

You are intermixing terms.

"Regen" = regenerative braking.
When standing still there is no regen.
But there can be "generating" also known as charging or recharging.

I'm saying we WANT generator resistance on a cold open loop engine.
In mine, I only get the lurching when my battery is 70% "full" and no recharging is allowed.

But I'm always above 28°F.

I suspect the same effect would present itself at lower than 70% if the battery were too cold to recharge, or recharge with any meaningful current.

 

[HeyBales]

at least on the Toyota I read there is a clutch to dampen sudden torque. it's not the kind of clutch that can completely disengage or anything - it just smooths things out. the one complaint I read about some toyota eCVTs was a little "shudder" when the engine starts but I haven't found anything describing like what happens on my maverick. The clutch is mentioned in this commonly posted video:





the good news is that it's rare but to to say it's anything other than a failure or a bug or whatever you want to call it doesn't seem accurate. a poster above actually hit another vehicle because of this. fortunately no damage or injuries but what if that was a kid crossing the street in front of them???

Maverick has a damper too. You can see it mentioned in Weber videos on the Ford eCVT.

That level of pull and not enough brake hold seems an outlier to what most see.

 

[HeyBales]

You are intermixing terms.

"Regen" = regenerative braking.
When standing still there is no regen.
But there can be "generating" also known as charging or recharging.

I'm saying we WANT generator resistance on a cold open loop engine.
In mine, I only get the lurching when my battery is 70% "full" and no recharging is allowed.

But I'm always above 28°F.

I suspect the same effect would present itself at lower than 70% if the battery were too cold to recharge, or recharge with any meaningful current.

Ya - corrected post.

I've had the shake and shimmy when below 20 F and below 70%, but to your point - not a lot of charge being sent back right then since still sitting and cold HVB.

I've missed my opportunity of cold to notice after my downhill and regen heatup of HVB, would sitting at stoplight still allow it?
Usually the lost cat/coolant temp from the downhill was quickly made up sitting with ICE on, and it may turn off if I didn't remember to turn the heater on.
Usually watching the highway traffic deciding if I really want to get on or take alt route, so not noticing really low shimmy.

 

[Mavster Mechanic]

And when above 50°F ambient the engine / battery / catalyst temperature is hot enough not to matter in 2 minutes.

In the first 2 minutes a lot of people won't have any stoplights or stopsigns.

 

[HeyBales]

And when above 50°F ambient the engine / battery / catalyst temperature is hot enough not to matter in 2 minutes.

In the first 2 minutes a lot of people won't have any stoplights or stopsigns.

Even at 20 F - usually within 40 sec of running, the cat was at 1000 and idle RPM was smoother.

 

[Red Eyes - Wide Shut]

I can tell you how to make it happen 100% of the time. With the truck sitting for at least 4 hrs or so and is Absolutely and completely cold, not driven. In any weather accept hot, like above 80. Start vehicle, drive without ICE running for a block. Stab gas pedal to start ICE. Stop within a block or so before driving at higher speeds. Vehicle will do the dirty every time. After that all seems normal when you stop. The high idle slows and warm up has taken hold. I can also do this in Sport mode during first take off to insure a sudden start up on my street before I stop to enter normal driving and it happens every time. So now I know some will answer and say this is somehow my fault or my imagination.

 

[MaverickDragon]

I remember the first time this happened to me. I looked in my mirror thinking someone just bumped me. Then it continued like aftershocks until it decided to stop. I realized it is this vehicle twitching Whatever this is and the justifications being made for it, it ain't right and it ain't normal. Whatever it is, the most important question should be, is this creating a situation that is causing damage or wear somewhere down the line.

I've never had that happen, and have frequently driven in lows well below freezing.
I mention this because a theme seems to be It apparently misbehaves when cold.

Perhaps something was modified between the 24 and 25 MY. IDK

The most important question isn't is it causing wear, it's that it could cause an accident if a driver wasn't providing enough braking force at the time of the surge.

Since you have experienced the issue, if you can replicate the behavior, bring someone along and document it in a video and bring it into the dealer, noting the conditions that precipitate it.

Without some evidence or input to create the problem, a tech will likely tell you "no trouble found".
They need to see a problem before they can address it.
Without seeing it, they may relegate it to a one off glitch, and glitches do happen, but are impossible to replicate.

You and anyone else with the same issue can file a safety problem with the NHTSA to document your concern, but identifying the conditions under which the problem happens will carry more weight, as will more than one report of a similar problem.

 

[Busa789]

I haven't noticed it at all on my 2025 and have been paying attention because of these threads. My morning routine is to back out of my garage, go down the driveway with electric, pull onto the highway in front of my house, start down the hill and the engine kicks on. I go 0.4 miles to the bottom of the hill and stop. No pulsing or shuddering at all. I pull away and drive highway for about 8 miles before the first intersection with a traffic control device. All the transitions of the engine/motor and motor/brakes are very seamless. I'm really impressed.

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