2025 Tundra Hybrid disable start/stop

Yes, there is a starter on the i-FORCE MAX.

 

Hybrid battery is probably very small, so engine being off is mostly brief moments of red light or coasting. I doubt it is every off for longer than 5 minutes at a time during a trip, but: ...

That is probably not very optimal. Cycling dry engine for a few seconds every once in a while. (I get it that there's still oil film present, so that might be its saving grace.)

 

it’s all about driving style and power demand. Within a couple days you can learn when it will turn on/off and you can manipulate it to shut off the engine and drive on the battery at speed.

everyday on my way home from work I get off the highway with the battery almost fully charged. Take off from the red light down a smooth double lane mostly flat main road and get to 60 mph. Let off the gas for half a second and the engine will shut off. I can then apply a little bit of pressure to gas pedal and can easily make the truck drive for 2ish miles on the battery power alone at speed before I get to a big hill or it needs to recharge again. It’s fun to make a game out of it and see how far you can go on battery power.

 

Another fun anecdote is in the summer time when i can get about 510-530 miles on 1 tank of fuel.
In the winter i only get about 450-460 miles because the engine seems to not shut off below a certain temp (37F maybe?)

so real basic rough math would say I can get 50ish extra miles on the hybrid battery alone per tank in the summer.

I know winter mix and summer mix plays a role and the electronics being used and such

 

It's not a few seconds - it is a couple, or even a fraction of, one engine cycle. I often drive for pretty great lengths with the engine off, especially in stop and go traffic where I can match the 'average' speed of the stop/go (say 1 mph) and just let the battery move my truck along.

 

Ok, that makes things less anxious. Thanks for input.

 

So we have only speculation and hope? Oil pressure is oil pressure and repeated loss of it is never good for an ICE. We don't need the oil pressure gauge to go to zero to tell us the ICE is not running. There is a big thing called the tachometer right in front and center of the driver for that, I think. Is there a check valve or something in place indicated in any parts diagrams?

 

This thread is getting silly.

Saying "I don't know how Toyota keeps oil pressure in check when the ICE shuts off, so it must be a problem" is like saying “I don’t know how the seatbelt locks in a crash, so I don’t trust it” even though millions of cars have been using that exact system for decades, and it’s been proven to work.

You don’t need to personally understand the mechanics behind every subsystem in a modern hybrid powertrain to trust it, especially when the automaker has 30 years of hybrid engineering behind it and a reliability record most others would kill for.

There are hundreds of components in your Tundra; solenoids, valves, clutches, sensors, specific viscosity oil, etc. that you never see or monitor directly, yet no one loses sleep over them because they just work. That’s not “hope.”

 

Just look at how long Toyota has been doing hybrids. Look at Prius’s easily going over 300k plus miles with no issues to the engines. Shoot, practically all Toyota hybrids have been pretty reliable with no major issues. Toyota has hybrids down pat

 

Nope, I go on... It just works. I'm much more concerned about other systems not working, that are known issues.
I'll say again, it's a non-issue

 

Not so sure on this. I recall a vintage of Tundra's having unpredictable (no warning symptoms) engine fails -

 

I think that is unrelated to hybrid system though, he was talking about Toyota's track record in hybrid tech

 

All is all. and yes, the hybrid system appears to be working as advertised.

 

haha he said practically all, if we want to be pedantic

 

Well that is true -

 

I can accept that you are extrapolating prior experience with the Prius hybrid system to expecting similar longevity from the Tundra hybrid system, as well as the lack of evidence of any widespread issues thus far with the Tundra hybrid system, with the provisos of noting the differences between the two engines and their duty cycles, as well as the length of time (or the lack thereof) the Tundra hybrid system has been in service.

 

That’s a fair and level headed take, for sure.

The issue I have is with people acting like the engine shutting off in a hybrid is some mysterious or risky behavior, when it’s a fundamental design feature that’s been in use across millions of vehicles for decades. Sure, the Tundra hybrid isn't literally a Prius, but the concept (controlled engine shutdown and restart) is not new.

This isn’t a case of Toyota saying, “Let’s hope it’s fine.” There are oil pressure management strategies in place, whether it’s through accumulators, check valves, or electric oil pumps, and while we may not get a flashy diagram of it on the dash, it doesn’t mean it’s magic or guesswork.

Absence of user-facing indicators does not equal absence of engineering.

If someone really believes that Toyota just forgot about oil pressure when designing a hybrid truck engine, then maybe they should also worry about whether the power steering actually works when turning left. We don’t see that either.

 

I can accept that "absence of user-facing indicators does not equal absence of engineering" but I would sure like to know what are these "oil pressure management strategies in place, whether it’s through accumulators, check valves, or electric oil pumps" on the basis of some factual evidence and not mere hope or speculation. At least one must understand that oil pressure is critical in an ICE, and I can also give Toyota credit for designing engines and vehicles generally very well, something that I know from my own long experience of owning Toyotas as well.

However, trust but verify is always a good principle to follow in my book.

 

Totally fair... “trust but verify” is a solid mindset, especially with new tech. I agree that oil pressure is critical in any ICE, and asking questions is always valid.

That said, my original point was never to claim I had blueprints or insider diagrams, just that the burden of proof shouldn't fall on the driver to reverse-engineer what Toyota's powertrain engineers already accounted for. We don't second-guess every subsystem we can't personally verify, because if that were the standard, no one would drive anything.

In the absence of credible issues or failures, I’m comfortable assuming the system is doing what it was designed to do... just like with ABS, airbag sensors, or active grille shutters.

Appreciate the thoughtful exchange, until next time.

 

Turn on Sport or Tow and it won't shut off nearly as much, problem solved.

 

its not the primary way the tundra hybrid starts the engine, it only used in specific conditions

i know of ...

extreme cold starts (pg 195 hybrid manual)
hybrid battery is to low to effectively start the engine (like sitting for a week or something like that)

i think those are the only ones i can remember

 

oh yeah forgot after fill ups also, so thats the 3rd condition. otherwise the hybrid motor usually is the starter.

the starter is there as a backup mostly for those 3 conditions i mentioned.