Surging when stopped. Anyone else?

[Mavster Mechanic]

This is that part that I was wondering about. I understand now about the lurching at a dead stop, like it wants to get down the road, and yes mine has done that from the beginning, but it’s the big lurch or thrusting forward at a slight downhill or somewhat downhill grade. Depending on my speed (only form leaving my house to the first stop sign and maybe the second one) it can be a good nod forward. Almost like you were nudged from behind.
First time posting but have loved looking up issues with my baby. Now 60k+

It happens (In mine)

When engine is "cold" or under 120°F

When truck is in warm-up mode.

When the hybrid battery is at maximum charge allowable.

Nothing is "broken".
Just a "thing" it does.

Solution - workaround to avoid that felling if it bothers you is:

Drive the last mile (or more) from electricity only. Park overnight with an empty(ish) or low hybrid battery.

Next cold start-up the truck will have some work to do recharging.

The act of charging acts as a shock-absorber / attenuator and you won't feel "lurching".

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[Gaidheal]

This is that part that I was wondering about. I understand now about the lurching at a dead stop, like it wants to get down the road, and yes mine has done that from the beginning, but it’s the big lurch or thrusting forward at a slight downhill or somewhat downhill grade. Depending on my speed (only form leaving my house to the first stop sign and maybe the second one) it can be a good nod forward. Almost like you were nudged from behind.
First time posting but have loved looking up issues with my baby. Now 60k+

I was driving the MY26 XL hybrid work truck the other day. Stopped at a red light, one car ahead of me. With no warning the truck surged forward and I hit the car in front.

No damage to either vehicle but the POS maverick is going into the dealer to see if there is anything they can fix so it doesn't do that again.

Level road, truck had been running for hours.

These things are possessed.

 

[sprubs]

I was driving the MY26 XL hybrid work truck the other day. Stopped at a red light, one car ahead of me. With no warning the truck surged forward and I hit the car in front.

No damage to either vehicle but the POS maverick is going into the dealer to see if there is anything they can fix so it doesn't do that again.

Level road, truck had been running for hours.

These things are possessed.

Whenever this has happened to me as long as I pressed down on the brake firmly I didn't move or if I did move it was a very small amount. Were you not pushing down really hard on the brake pedal? To be clear, I'm not saying this is your fault because this is 100% a design flaw and Ford needs to fix it ASAP before someone gets run over.

 

[Red Eyes - Wide Shut]

Whenever this has happened to me as long as I pressed down on the brake firmly I didn't move or if I did move it was a very small amount. Were you not pushing down really hard on the brake pedal? To be clear, I'm not saying this is your fault because this is 100% a design flaw and Ford needs to fix it ASAP before someone gets run over.

This is a more common than not issue. Many well wishers have ideas about this. It is the transmission engaging and disengaging at a high rate when you first start it, only when it is absolutely cold and has sat for a couple of hours. I've had mine in twice and the second time they reprogrammed the TCM. Said drive it a bit and should clear up. It hasn't. I was told by the tech," Don't worry you have a warranty". In this thread, I was told it is the engine fast idle I'm feeling,. Not so! Bring it in, get a record of this so some day it will be seriously researched. Don't get talked out of doing nothing.

 

[Mavster Mechanic]

This is a more common than not issue. Many well wishers have ideas about this. It is the transmission engaging and disengaging at a high rate when you first start it, only when it is absolutely cold and has sat for a couple of hours. I've had mine in twice and the second time they reprogrammed the TCM. Said drive it a bit and should clear up. It hasn't. I was told by the tech," Don't worry you have a warranty". In this thread, I was told it is the engine fast idle I'm feeling,. Not so! Bring it in, get a record of this so some day it will be seriously researched. Don't get talked out of doing nothing.

I understand this is unsettling and you don't like the way this vehicle behaves sometimes. Mine will exhibit this effect too.

Your description of "the transmission is engaging and disengaging" is not correct from a technical standpoint but it is difficult to describe.

Every part of the transmission is always engaged all of the time. The transmission has three main components and a planetary gear set.

Options when standing still.

A) nothing spins. In EV mode at a stop nothing spins. But everything is "engaged". No gears shift. No clutch lifts. Everything remains engaged with the output shaft-the wheels.

B) two out of three components can be spinning, the engine, and the generator. The traction motor is not spinning, but it is connected to the other two components that are spinning, and all three are connected to the output shaft-the wheels.

The "trick" to get the truck to stand still with engine and generator spinning at thousands of RPM's is: they must spin in equal and opposite directions, considering their gear ratios.

When asking the generator to make power, the engine torque while at a stop sign is absorbed, used, by the generator to recharge batteries. When your batteries are "full" the generator cannot take the torque of the engine. You MUST use strong brake pad force to resist the engine torque.

It's amazing it works as well as it does.

Now add to this complications of a cold engine. All engines run a little rough when cold. All engines run in "open loop" when cold.

Open loop means the air/fuel mixture is not being run by feedback from sensors. Because the sensors and the exhaust stream are too cold to be accurate. In open loop the truck is running at "best guess" of the air/fuel mixture based on past practice, not necessarily the precise conditions you have in the moment. This makes the engine run a little rough, and rpms may fluctuate more than usual and TORQUE output may fluctuate more than usual.

Workarounds: let your truck "warm up" in park for a few minutes when in sub-freezing conditions. 5 minutes should do it. It will waste 20 cents of gas but the choice is yours.

Workaround two: park with a low hybrid battery the night before, so the engine has charging work to do during the warm up cycle the next day. Being able to charge while warming up, even if by happenstance rather than design, has eliminated the lurching effect in mine by nearly 100%. I am never in very cold conditions. This works down to the +20's F for sure. Probably colder.

 

[Red Eyes - Wide Shut]

Thanks for the comments. I get it. This is my first hybrid and it has had it's share of issues from this to 3 dead batteries. Only time will tell if it does well. I don't like gambling. Something about 2 power sources y'd together seems more complex and also the unending quality issues. There are 2 things I won't do in the future buy a hybrid or this car maker. Possibly a Toyota as they have done this successfully for years. My daughter has a Volt and it is, I think the best concept for electric and gas. Many of the newer vehicles are using this approach. Electric drive with gas ICE generator. Similar to a train.

 

[sprubs]

Thanks for the comments. I get it. This is my first hybrid and it has had it's share of issues from this to 3 dead batteries. Only time will tell if it does well. I don't like gambling. Something about 2 power sources y'd together seems more complex and also the unending quality issues. There are 2 things I won't do in the future buy a hybrid or this car maker. Possibly a Toyota as they have done this successfully for years. My daughter has a Volt and it is, I think the best concept for electric and gas. Many of the newer vehicles are using this approach. Electric drive with gas ICE generator. Similar to a train.

I have a RAV4 Prime and while I've never experienced this issue it appears maybe some RAV4 hybrids (not Prime) have experienced it based on googling. My brother has a hybrid RAV4 and he's never mentioned anything to me about something like this happening.

 

[sprubs]

I understand this is unsettling and you don't like the way this vehicle behaves sometimes. Mine will exhibit this effect too.

Your description of "the transmission is engaging and disengaging" is not correct from a technical standpoint but it is difficult to describe.

Every part of the transmission is always engaged all of the time. The transmission has three main components and a planetary gear set.

Options when standing still.

A) nothing spins. In EV mode at a stop nothing spins. But everything is "engaged". No gears shift. No clutch lifts. Everything remains engaged with the output shaft-the wheels.

B) two out of three components can be spinning, the engine, and the generator. The traction motor is not spinning, but it is connected to the other two components that are spinning, and all three are connected to the output shaft-the wheels.

The "trick" to get the truck to stand still with engine and generator spinning at thousands of RPM's is: they must spin in equal and opposite directions, considering their gear ratios.

When asking the generator to make power, the engine torque while at a stop sign is absorbed, used, by the generator to recharge batteries. When your batteries are "full" the generator cannot take the torque of the engine. You MUST use strong brake pad force to resist the engine torque.

It's amazing it works as well as it does.

Now add to this complications of a cold engine. All engines run a little rough when cold. All engines run in "open loop" when cold.

Open loop means the air/fuel mixture is not being run by feedback from sensors. Because the sensors and the exhaust stream are too cold to be accurate. In open loop the truck is running at "best guess" of the air/fuel mixture based on past practice, not necessarily the precise conditions you have in the moment. This makes the engine run a little rough, and rpms may fluctuate more than usual and TORQUE output may fluctuate more than usual.

Workarounds: let your truck "warm up" in park for a few minutes when in sub-freezing conditions. 5 minutes should do it. It will waste 20 cents of gas but the choice is yours.

Workaround two: park with a low hybrid battery the night before, so the engine has charging work to do during the warm up cycle the next day. Being able to charge while warming up, even if by happenstance rather than design, has eliminated the lurching effect in mine by nearly 100%. I am never in very cold conditions. This works down to the +20's F for sure. Probably colder.

maybe you have answered this in here but I can't tell. what SHOULD be happening when the engine is running, the traction battery is full and the vehicle is not moving at a stop sign? I can't imagine the only option is for the engine to try to propel the vehicle forward. that would not be safe. I have to imagine this is some kind of control issue where the system is supposed to be doing something other than what happens when the truck tries to push me forward at a stop sign.

 

[Mavster Mechanic]

The engine isn't trying to propel the vehicle forward by very much.

Just the net forces are not always zero.

If the force on the brake pads is more than a little bit, none of this discussion is significant.

Every automatic transmission "creeps" forward when at idle. What's catching a few people off guard is the irregular feel of the idle in this case.

What should the driver be doing is a better question.

Keep your foot firmly on the brake at a stop sign is the answer.

 

[DannyUncanny]

The engine isn't trying to propel the vehicle forward by very much.

Just the net forces are not always zero.

If the force on the brake pads is more than a little bit, none of this discussion is significant.

Every automatic transmission "creeps" forward when at idle. What's catching a few people off guard is the irregular feel of the idle in this case.

What should the driver be doing is a better question.

Keep your foot firmly on the brake at a stop sign is the answer.

You can also just shift into park which makes the surging stop right away. I’ll occasionally do that if it’s very annoying and I have a long light.

Edit: and neutral works too

 

[Gaidheal]

Keep your foot firmly on the brake at a stop sign is the answer.

I do. That's how I know the EV coach shows increased power consumption when you push the brakes harder.

Didn't stop my MY26 from bumping into the car ahead of me at a red light.

Dealership appointment this week to hopefully get an exorcism

 

[DreamWeaver21]

You can also just shift into park which makes the surging stop right away. I’ll occasionally do that if it’s very annoying and I have a long light.

Edit: and neutral works too

This is what I learned do if the issue starts happening, pop it in N for a second or two and then back to D and the issue usually stops.

Most of the time, it is just a mild annoyance. ONE time, back when I posted the thread, I REALLY had to stand on the brake to keep the truck still.

 

[Red Eyes - Wide Shut]

It's nothing, really. Like a small seizure. Do like Fred Flintstone and use your feet.

 

[sprubs]

Most of the time, it is just a mild annoyance. ONE time, back when I posted the thread, I REALLY had to stand on the brake to keep the truck still.

this is the experience I've had a few times. it should not be like this to any degree though. as far as I know MG1 should be spinning to counteract whatever the engine is doing and what we are experiencing seems like it is a control system failure.

 

[Mavster Mechanic]

this is the experience I've had a few times. it should not be like this to any degree though. as far as I know MG1 should be spinning to counteract whatever the engine is doing and what we are experiencing seems like it is a control system failure.

Not a failure. No.

Ever hear the phrase "Nothing's Perfect"?

If you had a Lexus hybrid there would be something imperfect it in too.

If you had an EcoBoost Maverick there would be imperfect aspects too.

What many/most experience will be mild and "normal" for this vehicle.

There can of course be outliers with more serious issues.

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