Why does my car's RPMs increase when going up an incline but does not increase when I'm driving that same incline without cruise control on. My 2002 Sequoia doesn't do that. Is that a new thing?
Regards,
Randy
RPMs increase when going up an incline but does not increase when I'm driving that same incline without cruise control on
Yeah it’s normal.
It’s probably because the cruise control will downshift into a lower gear to maintain the target speed, whereas when you’re driving without cruise control turned on, your throttle input doesn’t meet the threshold where a downshift would be necessary and the speed would bleed off accordingly.
This is all assuming you’re driving in D, and not stomping on the pedal when going up the incline.
@itwt I have a 2002 Sequoia and a 2013 camry that doesn't do that. There is no need to downshift on every slight incline. I have been driving toyota/Lexus for 40 years and this is the first car that does this. I think it might something with the newer cars. It should consume more fuel it the RPMs keep increasing?
Yes, it will consume more fuel when not in top gear + higher RPMs.
@itwt I'm not being a butt...but mileage is not a factor. It has 62,000 miles on it. It could have 262,000 miles it will still behave the same
no offense but it sound like no one on her knows the answer
The GX 460 hasn't changed much in 10 years.
it has been in production for 23 years, and and yes it has changed. A lot. It has gone from V8 engine only , to V6 and i4 only. It has gone from non-turbo to turbocharged. From combustion to hybrid. The transmission evolved from a 5 speed conventional automatic, to a 10-speed direct shift. And a plethora of gadgetry that was added.
milage is not a factor
Scotty didn't put the instructions there for our amusement. We can't help you if you don't provide the information we ask for. If you knew what the factors were, you wouldn't be here. So please, let us be the judges. You wouldn't tell your doctor "you don't need my temperature. I self diagnosed and it's not a factor".
I have a 2002 Sequoia and a 2013 camry that doesn't do that
You cannot compare different vehicles with different engine power bands, different weights, and different shift points. A 23 year old vehicle will not have the same level of sophistication.
RPMs increase when going up an incline but does not increase when I'm driving that same incline without cruise control on
Lexus are a luxury line with all kinds of bells and whistles, which a Camry will not have. For example:
- a pretty sophisticated radar assisted cruise dynamic control system.
- "Safety System +" with additional sensing and control ( https://www.jdpower.com/cars/shopping-guides/what-is-lexus-safety-system-plus)
- Electronic Throttle Control Systems
If you open your owner's manual you will it also has "AI-SHIFT". These days, transmission can adapt themselves to changing road conditions and driver behaviors.
AI-SHIFT automatically shifts the gear to the suitable position according to driver perfor-
mance and driving conditions.
With all those control systems, it would not surprise me in the slightest if the CC system was designed to minimize shifting to give the experience of a smoother ride.
It should consume more fuel it the RPMs keep increasing
The computer has tables to compute the RPM range for peak engine efficiency. More fuel is consumed if engine speed is above OR below the range. The optimal RPM changes dynamically according to engine load, transmission gear, terrain, weight, throttle position, etc.
I have talked to other drivers that have the same model that I have and it does the same thing. It appears that no one on here knows the answer. I wonder what Scotty would say
@fishingandcarsenthusiast123
I already get a notifications when somebody replies to my comment. I don't need another. Scotty doesn't look at notifications at all. Dan hasn't been here in a long time. I'm confused why you thought it was necessary to ping all these people for an ordinary question?
@imperator I didn't realize you got the notifications automatically.
@fishingandcarsenthusiast123 don't you? 🤷♂️
@imperator well now I do...
@fishingandcarsenthusiast123 I'm saying, don't you receive notifications of replies to your comments? So why wouldn't I?
@imperator good point!
It has 62,000 miles on it. It could have 262,000 miles it will still behave the same
Once again you are wrong. Engines lose power over time. So no, an engine with 262k miles will not behave the same as one with 62k
I have talked to other drivers that have the same model that I have and it does the same thing.
Which is evidence to prove my point that it's programmed into the vehicle.
In other words, it's totally normal. Enjoy driving your car.
no offense but it sound like no one on her knows the answer
You were given a number of reasons, but it seems you know better than everyone. So why even ask?
If you want to see the lines of codes in the programming then I guess you'll have to find a Toyota design engineer.
Good luck.
I have a toyota sequoia with 389,000 miles and preforms the same as it did new.
@rmccoycell what were the dyno and cylinder compression test results?
year? engine? hybrid? throw us a bone please
GX 460, v8 engine. No hybrid. The GX 460 hasn't changed much in 10 years. I've heard that other cars are doing this also. I'm surprised that no one else is curious about this down shifting. These are slight inclines. I have owned over the last 40 years nearly 10 toyota models and none did this.
It appears that no one on here knows the answer.
You were given answers, you just aren't satisfied with him.
I wonder what Scotty would say
Scotty chooses a handful of topics each day to answer himself. (Obviously he cannot answer them all.) He also will sometimes answer questions posed here in his videos.
Your answers has not explained why my car increases it's RPM's when there is no reason. I would expect a newer car cruise control to be more efficient than an older car.
There is a reason, as has been explained. You could always check to see if there is a TSB regarding the cruise control with a software update available that might bring its operation more in line with your expectations.
You've asked if this behavior is something new. It's not new. Downshifts and higher rpms while using cruise control is to be expected. It's completely normal.no offense but it sound like no one on her knows the answer
Every Toyota or Lexus that I have owned over the last 40 years didn't increase RPMs over a slight incline. I will email Toyota USA. I thought this forum would have quick answers.
@rmccoycell Even my 29 year old Tacoma downshifts while using cruise control. My 2003 Avalon did it, as my 2004 Camry, the 2006 Corolla and my 2011 Camry. Toyota's cruise control has performed the same way for me in multiple vehicles for almost 3 decades.
Please provide all vehicle details as requested in the posting instructions as well as what diagnostic steps you have taken so far.
2021, Lexus, GX 460, automatic, milage is not a factor
It should consume more fuel it the RPMs keep increasing?
Yes, every time you double the engine's RPMs, your fuel consumption increases by a factor of 4. It's physics at its most basic, and you can easily verify this with any scan tool that has live data. Changing gears changes the torque that goes from the engine to the vehicle's wheels. Lower gears increase torque while decreasing gas mileage, higher gears increase fuel efficiency but sacrifice torque. torque is required to push a car up a hill, not horsepower.
The Lexus GX460/ Toyota Sequioa has gone through several iterations since 2002. The transmission in the 2002 Sequioa is a 5-speed, the one in your new Lexus is a 10-speed. Governments have mandated getting the most miles as possible from a gallon of gas, so Toyota is increasing their "speeds" to compensate. A lower number of speeds equals a less efficient engine. There's no way around it. In cruise control, apparently when the car senses it's going uphill, it downshifts a gear to keep the engine running at its most efficient. When you're manually using the gas, it might be slightly out of its most efficient range (RPMs are a little too high, even though it is delivering sufficient power to the wheels) but it still makes it up the hill.
After the transmission, there's a differential that you must take into account... In short, there's a lot more than meets the eye.
You have give the most comprehensive answer that I have seen. The Lexus manual says using the cruise control is the best way to increase your MPG. What you just so elegantly described is the opposite of that. If it down shifts to get up a slight incline(not hill) increasing torque, it consumes more fuel. If I travel over the same incline with cruise control off, my RPMs stay at 2000 rpms and my speed is constant at 75 mph. The car never down shifts. There is more than meets the eye.
It's not some conspiracy theory that using cruise control unnecessarily decreases MPG when you go up slight inclines (inclines are hills). If you want to keep believing in nonsense, that's on you.
I don't believe in conspiracy theories. I don't know what you means "using cruise control unnecessarily"???? Does your car behave in this manner. It is not nonsense that all of the 10 models I've owned in the past increased my MPG when using cruise. So the Lexus manual is wrong, it says if you want to maximize MPG on trips you should use cruise control? Now that could be your conspiracy theory. If you haven't experienced what I am seeing. Then all you have are theories.