Random high revving

[1Guy1Truck]

Consider if ice is charging HVB and charging 12v and running the electric heat pot for the AC,plus Ford knows what else when you put selector in reverse the small generator may need to run at max. Also if the AC is in cool mode the electrical compressor may also be running really loud adding to the noise level. Next time it does it just turn AC off and see how much the noise reduces.

Ac was not on. It’s never done this in 60,000 miles.

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[Glen Baker LLC]

Ac was not on. It’s never done this in 60,000 miles.

I totally understand what you're talking about. It's just like somebody mashed the pedal on a regular ice engine.
That's why I thought I caught the accelerator with the side of my foot while I was pressing on the brake pedal. And it wasn't any of these charging, air conditioner, heating theories
We are not the only ones.

I had a strange occurrence a few days ago in my 2024 hybrid XL. Truck has 1250 miles on it. I was parked in front of my garage. My driveway slopes down and has a turnaround. I was backing into the turnaround so i could drive down the driveway. I think i may have put it in Neutral instead of reverse when i was backing into the turnaround. When i stopped in the turnaround, i noticed the engine racing, probably at least 3500-4000 RPM. I looked at the shifter knob and it was in neutral. I shut the truck down, waited a minute then restarted. All seemed normal after that. It has not reoccurred. Anyone experience this? It has been fine ever since.

 

[Dad]

I think it is electric motor only for reverse so if maybe your battery charge was too low, too cold, or a combination of both the ICE engine was trying to really over compensate in order to reverse the vehicle?

When you put in drive did the ICE engine shut off or RPMs just fall back down to normal?

This sounds like the most logical explanation. Another "Maverick Mystery".

 

[Phimosis]

You say it was redlining. So how many rpm was it spinning? Or are you just guessing, based on sound? As others mentioned, this sounds like a low battery issue and it was using the ice to recharge the battery. Atkinson cycle engines do not make good torque at low rpm. So to be able to effectively load the engine to generate electricity, it needs to be spinning at least 2,500 rpm and it can be up to 3,500 rpm. I have never driven a Maverick hybrid, so I’m not certain about this behavior, but I have had 2 Priuses and they exhibit the described behavior. Also, revving the engine to higher rpm than its hp peak with a CVT gains nothing and only loses efficiency and increases engine wear. So in general, the redline in a hybrid is the same as its peak hp output, which means that the Maverick hybrid is most likely programmed so the engine never spins higher than 5,600 rpm.

 

[1Guy1Truck]

You say it was redlining. So how many rpm was it spinning? Or are you just guessing, based on sound? As others mentioned, this sounds like a low battery issue and it was using the ice to recharge the battery. Atkinson cycle engines do not make good torque at low rpm. So to be able to effectively load the engine to generate electricity, it needs to be spinning at least 2,500 rpm and it can be up to 3,500 rpm. I have never driven a Maverick hybrid, so I’m not certain about this behavior, but I have had 2 Priuses and they exhibit the described behavior. Also, revving the engine to higher rpm than its hp peak with a CVT gains nothing and only loses efficiency and increases engine wear. So in general, the redline in a hybrid is the same as its peak hp output, which means that the Maverick hybrid is most likely programmed so the engine never spins higher than 5,600 rpm.

The hybrid has no tachometer so I’m going by sound. It has 60,000 miles and it’s never once done this and I’ve never once heard it rev even close to this loud. I’ve been driving for 25 years and I am pretty certain what redlining sounds like.

 

[skinnyboy]

My '22 just did this for the first time in 75k kms. creeping out of a parking lot. Far higher revs than it has ever done for battery charging in the past, and my Prius never charged this hard either. Only lasted a few seconds but was definitely out of the norm. No recent software updates.

Cheers.

 

[FavDesertCactus]

yep.. ive had it happen to my 2022 hybrid xl a few times too. no rhyme or reason to it. Starting the car on a normal temperature day like 65 degrees outside. had just got in the car, turned the key and backed out, then switched to drive for some 5-10 mph driving on a flat driveway and wham - the car starts revving (by the sound of it) to somewhere like 4500-5000 rpms and holds there for a few seconds. then does it again, then suddenly back to normal. really really strange...

 

[Cherokee]

FWIW, I have found my truck loves engine braking and will stay in a lower gear a lot longer than I would prefer. Especially when I pull into my neighborhood and am rolling down the hill towards my house.

Probably not related to this but it is something I noticed.

On my way home my 2024 Eco revs up to 1900 rpm when I roll from a stop sign then down a steep right turn. I only drop 25 feet.
somewhere in the curve if I accelerate a little it up shifts and the tach falls.
BUT !
If I do the same thing or any other descent in ECO mode it
Rolls free without speeding up the engine above say 1400 rpm.

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