Getting Used to 2nd Gen Acceration......

Howdy,

Took a 50 mile drive over some winding roads today. 55-65mph range.

When accelerating from a stop to get up to speed faster I noticed a bit of a drag when smoothly pushing accelerator pedal. When I punched it no problem! Nice impressive take off.

2013 V6 4X4 Sport 40K. New air filter, aFe Dry, and all new fluids double checked for accurate level.

I'm wondering if this is a computer, learned driving issue as its a new vehicle to me, got it ~7 weeks ago.

Does the "computer" relearn or do I need to reset it?

Thanks,

W

 

When you punch it, it downshifts, yielding significantly greater torque to the wheels, hence it accelerates faster.

 

These trucks are drive by wire, meaning there is no physical connection between the gas pedal and the throttle plates. It's all done by electric servos, resistors and motors, and controlled by the computer. The computer is programmed to favor fuel economy during normal driving, so moderate throttle inputs don't give much acceleration, but enough for normal traffic situations. When you mash it, economy goes out the window and you will get the power you need. Not sure if the computer adjusts based on the driver's habits... if so, this learning would happen over a long period of time. Hope this helps you.
Strangely, my 2.7L gives better acceleration off the line if I go half-throttle. Wide open makes a BUUUUUHHH bogging sound and not as much acceleration as half throttle. This is only true from a standing start.

 

Place the shifter into 4th gear when you want to drive more 'spiritedly'. The transmission will shift through gears 1-4, but will have more of a sporty feel when shifting - it almost feels like its allowing the shifts to be based on performance rather than economy. It will be more responsive to downshifting as well. It does not keep the transmission permanently in 4th gear, and it will avoid the transmission from shifting into 5th. Other Toyotas are like this too which feature 'only' a 5 speed auto (ie. Rav-4 V6 has similar behavior ). Separately, I also drove a Kia SUV as a rental not too long ago which had Sport shifting mode as well as economy and normal modes - with the Kia in sport mode the transmission behavior was exactly what I described above. When on-demand responsiveness isn't needed, stick the transmission into D again.

After warmup but before the engine heatsoaks, the truck WILL have more punch during cool, dense air mornings when the ambient is 70ish. The truck will feel like it has more 'pull' on its own with less throttle input. But thats only on certain conditions and occasions, and is hard to repeat. In the cold weather, it is what it is as well as in hot summer temperatures.

 

I've never experienced this nor heard of this before

 

Hmmmmmmm

 

Have you gotten the TSB for engine knock done to your truck? My acceleration was much better/smoother after the TSB on my 2014. IIRC, the TSB covered 2012-2015.

 

Every vehicle I've ever owned has accelerated faster when I punched it.

Well, almost every vehicle.

 

haha!

Yep obviously! I mentioned as it seemed to suggest an isolated issue. I've had this issue on other vehicles when punching it actually had a flat spot, a lag.

W

 

I keep in 4th unless over 50-55 and straight roads. I treat it as a 4 speed with over drive

W

 

Did you change the spark plugs at 30K?

 

Not sure... is that standard?

I got it used at 38K from a dealer and previous owner got all the maintenance done regularly at Toyota. The Toyota Owner page with maintenance records is down now but is that something that would be done?

I was considering this.....

W

 

Yes, per the owners manual 30K for plugs.
If they were changed they will all be the same brand.
If they were never changer you will have NGK on one side and Densos on the other side.

 

Same with my V6 auto. WOT bogs it down. Like 3/4 pedal seems to be the sweet area for maximum fuel burn to speed gain ratio.

I've also had times I've started to accelerate, realized I needed to pick up speed faster, mashed the pedal, and had nothing happen.

 

The non-linear throttle response curve serves more purpose than just fuel economy. If you maintain a linear throttle response curve, then as engines become more and more powerful, the sensitivity of the throttle lever increases. Consider a 100 hp engine in the same size of truck, if it cruises at, say 50 horsepower and you want to up the speed a bit, you push down a bit on the throttle, bump it up to 51 hp. If your engine is 300 hp and you push the throttle the same amount, it bumps up from 50 to 53 -- three times the increase in power for the same amount of motion. This can become difficult to control at a certain point.

So if most of your usage will be in the 0-75 hp range, you decrease the sensitivity so that 3/4 throttle will be about 75 hp, and then the remaining 1/4 throttle will bring it from 75 to 300 hp.

Now that is the general idea of it, but of course, its implementation is somewhat more complicated than that. Different driving gears to make different torque, and adaptation to the actual driving *speed*, etc.

That is actually more in your head than in reality. What is happening, is that you are actually accelerating the rate at which you are lifting up off the clutch. That pulls the engine speed down lower than it goes when you aren't trying so hard to accelerate quickly. To some (smaller) degree, it might also confuse the VVT, since you're starting off with low load, low throttle, high speed (engine), so its going to try for "efficiency" timing, then when you dump the clutch, the valves are timed for efficiency rather than torque, and it doesn't go anywhere fast.

So if you want to overcome this, you need to either keep into the clutch a bit and let it slip (which obviously will wear your clutch faster), or don't be so much in a hurry to come off the line, start it at half throttle, then when the clutch is fully engaged, stomp on it.

 

^ mine's an automatic. No clutch to dump. But thanks anyway

Exactly. My 2.7 launches best at about 1/2 throttle until RPMs start to climb. Once the RPMS climb past 3000, WOT is very effective... as effective as it can be in a 2.7 *smirk*

 

Where do you come up with computer controlled throttle? I think you will find that they are 100% linear electronic yes but only related to to your foot other wise every one would be getting the same fuel mileage. Your foot is the input it has nothing to do with HP it matters not if it is 1000 HP or 50. There is throttle position sensor but that is related to nothing more than where the throttle shaft is at any given time it doesn't control it, it is controlled by your foot and the throttle motor matted 100% half way 50%.

 

Lolz AT problems

 

No, it certainly is NOT linear.
The throttle pedal signal is fed into the ECM. The ECM controls the throttle position.

How do you think the cruise control works if it was just a direct link between the throttle pedal and the throttle gate? The cruise control switch is another input to the ECM.

Or how about the anti-runaway software that tells it to cut off the throttle when you're on the brake? (hint: The brake switch is another input to the ECM).

Or how about the WOT transmission kickdown? I promise you, there is no cable hooking the throttle lever to the transmission like there were in the 80's.

THE ECM (A "computer") controls the throttle position.

Just take a look at the WIRING DIAGRAM. The "accelerator position sensor" has six wires. ALL of them connect **ONLY** to the ECM. Also the Throttle Body Assembly is controlled EXCLUSIVELY by the ECM.

 

Just put it in "D" and drive it. Better mpg that driving it in "4".
They have fair acceleration for what they are, a truck with low hp to weight ratio.
They're not Mustang GT's or Camaro SS.