Sticky Throttle-by-Wire?

Car is a 2009 Hyundai Sonata with 60,000 miles and electronic throttle-by-wire. Throttle sometimes has poor response and/or a dead spot off idle. It most frequently manifests itself after a rolling stop the throttle gives zero power until the pedal reaches 20-30% then wammo, you get power.

This is covered under warranty but the dealer has done little so far beyond make helpful noises. Car throws no codes. Problem is intermittent.

Any help? Comments? Is this a common problem with e-throttle or Hyundais in particular?

Any and all wisdom is appreciated! Thanks!

I have a subaru WRX and when you put in the clutch after revving it will continue rev a bit up but it doesn't affect it when it's driving. Throttle by wire is just E36 M3 I wouldn't doubt if you brought it in if they say "working as designed" but I don't know how the Hyundai system is.

I drove a 2007(I think) camry that did that, I think it was supposed to be that way.

May well be deliberate in the coding. Current Volvo suffers similar lag problem, and it is meant to. Various excuses, but it essentially covers up wear and damage on the throttle plate sensor that screws up feedback to the CPU.

Secondary part of it is that it's deliberate to cover up, er, smooth out the shifting problems with the transmission. It delays throttle response, or decreases throttle, in order to allow for the transmission to shift smoothly. But since the transmission frequently delays its shift, you get a dead throttle, then a wham action shift when it finally decides to pick a gear.

Our '09 Honda Fit(automatic) does the same thing. I asked here about it once, and someone suggested it some emissions-related code in the programming.

And why is fly by wire a good thing? Can an automaker out there actually give any good reason why it is good for the consumer?

I travel every week, get to drive a lot of different rental cars, and this is a common problem.
Seems like a massive safety issue, ie lawsuit waiting to happen.

dean1484 wrote: And why is fly by wire a good thing? Can an automaker out there actually give any good reason why it is good for the consumer?

E-throttle is necessary for hybrids or cars with robo-manual gearboxes. On other cars they can improve drivetrain life, emissions and crappy drivers' inputs but at the cost of good throttle response.

An E-throttle could work just like a mechanical throttle, they're simply not programmed to most of the time.

What's the consensus on 'reprograming' the computer? (i.e. disconnect the battery so it has to re-learn how you drive) I had a brand new rental car (5 miles on it) and by the end of the week it was not nearly as terrible of a delay. But we drove it like a rental Aveo should be driven!

The dead spot helps for smoother take offs, making it easier on the transmission, engine, (rear end,) and fuel economy. No more semi-jack rabbit starts.

My 06 F150 has the same thing. It's annoying, but once you learn to let it take it's time or just to stab the throttle through it, you'll be fine. Of course that Aveo didn't have the stab through ability...

My fiancee's '10 Yaris has a jumpy throttle. Real hard to get an easy start when you have fragile things in the back.

Another reason for throttle-by-wire is that it makes engine packaging easier. Engineers don't have to deal with running a cable in a certain way so it doesn't bind. This is especially a big deal in platforms that are supposed to be shared between left and right-hand drive markets. Just put the throttle body wherever it needs to be, and run wires. Done. Reduces design cost.

Regarding your question, have you checked for gunk buildup at the throttle body? That's a pretty standard cause of that kind of problem. I realize your car is very new and unlikely to exhibit this.

From an engine management standpoint - drive by wire allows you to anticipate the airflow, which can mean better fuel mapping and throttle response. Consumers like those.

It could be a sensor problem in the throttle, too. I've seen that sort of behavior with a worn potentiometer in an airflow meter, dead spots can cause odd fuel surges.

Wow, I've driven quite a few TBW cars and have yet to experience this.

I have, however, had a gunked up throttle body on my non-TBW cars cause this.

If I pretended you didn't already suspect a strange throttle control issue, I'd expect fuel or spark issues. Why are you so quick to expect it's NOT those issues?

Bryce

I thought I saw some dohicky advertised in GRM that plugs between the throttle pedal and wiring harness and is supposed to correct the lag.

bgkast wrote: I thought I saw some dohicky advertised in GRM that plugs between the throttle pedal and wiring harness and is supposed to correct the lag.

Some cars like the WRX can get rid of this issue by flashing a custom tune to the ECU. My old WRX had this issue and it was infuriating. I didn't reflash it because I wanted to keep the car under warranty. I guess the reason for this has something to do with keeping the catalytic converters up to temp so emissions are lower.

The "dohicky" just increases the output signal from the gas pedal, giving you a wider throttle opening for a given depression of the pedal. It won't correct any downstream issues like bad sensors, and might even make the problem worse by making it slam harder when the sensor finally does catch up to the input.

Keith Tanner wrote: From an engine management standpoint - drive by wire allows you to anticipate the airflow, which can mean better fuel mapping and throttle response. Consumers like those.

TBW also gives a much smoother cruise control function, and can enable less-intrusive traction control. On a turbo car it lets the computer open up the throttle wider to spool up the compressor more quickly, then close it back down again once the boost level has risen.

The annoying parts of TBW are usually attributable to either emissions regulations or lawyers.

Or just plain crappy programming.

I can tell you that the E39 M5 (with 8 electronically controlled throttles) has the least intrusive cruise control I've ever experienced. 400 hp might be a factor.

I bought a used 2005 corolla with 100,000 and it had the same problem. Fixed it by putting in new factory correct spark plugs. They were extremely well used. Take offs are much smoother now.

Also had a navigator that did that but its was not dbw.