My 2007 Chevy Impala with the 6-cyl engine is, overall, a nice car. One thing I just do not like about it, though, is the electronic throttle. There is a quite annoying lag between acceleration on the gas pedal and response from the car. It isn’t just my car, all the Impalas and other cars I test drove when shopping for the car are the same way. Even the 2007 Buick with the last year of the 3.8 L engine had a touch of lag time compared to the 1987 Olds Cierra I had with its 3.8 L engine and mechanical throttle. I’m no lead foot but when I want acceleration I want it now and not later. Guess I got spoiled from 20 years driving the '87 with its giddy up and go.
When making left turns without a traffic light, I have to allow a much wider open slot in oncoming traffic than I ever did since driving the 1973 Toyota Corolla with its four weak hamsters under the hood.
I’m not the only person I’ve heard gripe about electronic throttle. I have to wonder what about drive by wire is superior to mechanical throttle if it slows down the throttle response so noticably???
…still asking questions, still reading, still learning
With EVERYTHING being electronically interconnected, it’s now the only way.
Even my 92 Explorer was electronic accelerator even though there was a cable from the pedal to the throttle body…it went to a lever that not only opened the air inlet butterfly but worked a…throttle position sensor !
Injectors, cam and crank sensors, throttle response, air flow sensor, transmission shifting, multiple temperature sensors, fuel pump, speed sensors, etc…all computer connected .
I too am somewhat displeased with the computer logic lag time in both my 08 Expedition and 06 Escape hybrid. But once used to it it has become easy to allow that extra second then both of those get up and go like bat outta’…
now my 79 'chevy pickup…THERE’S a world of difference there…even just starting the carburated beast take some memory of how to do that. But when you stomp on it, it screems…as does the wallet paying for that 4 barrel guzzle.
computer accelerator logic ;
"Oh, so you SAY you want more gas ? Why ? you’re not rolling any faster , why should I give you more gas ?“
Foot says, " I cant roll any faster untill you give me gas.”
“But you can’t roll much faster till you tell me, the transmission , that I need to shift.”
“but if you want more gas I need more air too.”
“Hey, what about us injectors ? Don’t you think we need to know this too so we can fire faster ?”
“But how will you know when to fire if we cam and crank sensors don’t tell you where the cylinders are ?”
"Who’s in charge here anyways ? "
LOL @Ken Green…Love the computer debate about allowing acceleration. Never have thought of it in those terms but it does make more sense to me now and with a good chuckle while digesting the education. Thanks for both the explanation and the laugh.
We just bought our third car with an electronic throttle; all GM cars made in the US and one with a manual trans. I have noticed no difference in operation from a mechanically connected throttle except that with the manual trans car, there is a very short lag until the engine slows when the throttle is released. That is for emission control I would guess. It works ok when you account for it when timing throttle and clutch release while shifting.
The earliest car that we had with an electronic throttle was an 08. Possibly the lag that you mention was eliminated after 07.
It seems like there would be no reason the throttle response would be delayed b/c of an electronic throttle. It’s just an electric motor is doing the job that the cable connected to the pedal would otherwise do. I suspect – as someone above mentioned – the delay is purposely put in so to improve mpg. If you can’t stomp on the pedal, you’re going to get better gas mileage. And mpg figures sell at the dealership, so the vendors would have an incentive to purposely degrade the throttle response a bit.
Well, it’s not ‘just a motor’. It’s a position sensor that sends a signal to the computer that thinks about it, then sends a signal to the throttle to open X degrees. So some lag would be expected, but with fast chips it wouldn’t be much these days.
I have an '09 Caravan with electronic accelerator. The difference that I don’t like is when it is on cruse control. the petal is still up and there is a big gap from there to where the engine is running. I like to have it under my control when I turn off the control. Most people never notice or give a flip about it. Many also going down a straight, level, road, keep downshifting and upshifting an automatic because they can’t keep a constant speed.
@EllyEllis: There is a hill I drive almost every day with a 40 mph limit but traffic when heavy often goes about 35. When at that lower speed on the uphill the transmission spends a lot of time shifting up and down searching for where it wants to be. If I go a bit faster or slow down some it stops that. The only time the transmission hunts for gears is under load, uphill at about 35 mph. Never have had any other car do that. Again, one of those differences I just had to get used to. Every car has its quirks.
It still beats the “thrill” it used to be merging onto the highway with the 4-cyl hamster powered 1973 Toyota Corolla I had for my first car. Talk about slow acceleration, that was it! LOL
At the moment, I have two Crown Vic P71’s a 2005 and a 2006. Outwardly they are identical except for the wheels (16-17 inch)…But driving, the 2006 is crisper and quicker to respond to big changes in throttle position…Also, the transmission gets itself into the correct gear quicker, so acceleration demand is almost seamless with the 2006…You would never notice this unless you drove one car and then the other…It seems these computerized control systems continue to improve…
The gas pedal is a request now rather than a command.
An electronic throttle has the potential to be FASTER than a mechanical one. How you say? By calculating the speed at which the pedal is moving within the first few degrees of motion and predicting where it will end up. Very well known and established predictive control algorithm in use in various applications, some more safety critical than automobile accelerators. However, I wouldn’t begin to suggest it be used in a passenger vehicle, just pointing out the potential.
I see a purposeful lag as a potential for litigation. Ladies and gentlemen of the jury, my client attempted to floor his vehicle to avoid a collision but due to the purposeful lag introduced into the design of this vehicle, for the dubious purposes of emissions reduction, he was unable to escape injury and therefore we hold the manufacturer liable.
That being said, the electronics in use today are more than capable of achieving near real time response. Some hysteresis would be desirable regardless to eliminate jerking action from too rapid a response. Why they would have such a noticeable lag on first application from a stop is curious…I have two DBW throttles and neither has any noticeable lag on acceleration from stop.
Interesting comments Caddyman and Twin Turbo. Thanks for the input.
I will say that when my car was being repaired last autumn from the encounter with the road hazard, I had two different rental vehicles for a couple of days. The 2012 Camry actually had better throttle response with a 4-cyl engine than I get from my 2007 Impala 6-cyl. I also drove a 2012 Chevy Equinox (don’t recall if it was 4 or 6 cyl) for a day and found its throttle slightly better than my car’s but with a transmission that gave horrid jerky gear seeking until I figured out to disengage the “eco” mode. So perhaps my real gripe may be with GM throttles and transmissions.
It ain’t the electronic throttle that’s the problem, it’s the regulators. The ones in Washington. Unfortunately, there doesn’t seem to be any “fix”.
There do, however, seem to be other manufacturers that seem to bne able to meet CAFE requirements and still provide some scoot. The only solution I can offer is to look for a peppier replacement.
Actually, I’ve started researching and will do some test driving so that the next time anything major goes wrong with the Impala at a far lower mileage and age than it should I will be prepared with a short list of models to consider replacing it with. It already needed the power steering pump and rack and the the water pump replaced at well under 40k miles. Normal proactive maintenance and wear items don’t bother me. It’s part of keeping the machine running. But two major component failures at very low mileage have me a bit wary.
The advantages of keeping the car are that it was fully paid for the day I bought it, it still has low mileage and is in very nice condition, and has the split bench seat with the shift lever on the steering column which I highly prefer and is no longer available (weep, wail, gnashing of teeth!) Also, I just spent considerable money on three struts, four tires and one wheel bearing courtesy of the road hazard incident. Insurance only covered one strut and the body work. So I’m not anxious to spend money on a new car.
Also, our family always keeps cars many years and up to high mileage. Between my parents, my brothers and I we’ve driven cars anywhere from 16 to 26 years and an average of 180k to 280k miles. The idea of swapping this one at barely 7 years and 50k seems so…wasteful.
On the other hand, I’m not married to the car. If I happen to find something that is significantly more comfortable and enjoyable and that I can afford, then I’ll make the switch. But when I do, the trusty trash basket that is almost 50 years old, in stellar condition, and is currently doing duty in its fourth car stays with me and goes into the next buggy. Its the perfect size and shape, fits over the floor hump with weighted flaps hanging down both sides to hold it in place, and there simply isn’t anything like it available anymore. One friend joked that I’d be more upset to lose the trash basket than the car itself. Almost true! LOL
You certainly seem to have had your share of hiccups with that car Marnet. More than usual.
Maybe that one was assembled during a time of tense UAW contract negotiations…
Just some food for thought, but if this hesitation is annoyingly bad maybe it could be due to something caused by service at some point in the past. Any kind of air leak, especially with the intake tract between the throttle body and MAF sensor, could possibly cause a hesitation.
