Hyundai Genesis Coupe's unintended acceleration - Hyundai blames wrong wheel size

[KDKPSJ]

So, here's another fun story of unintended acceleration. This time, from Hyundai and Korean buyer.

There was a Korean buyer who experienced the unintended accelaration with his Genesis Coupe 2.0T MT. He brought it in for the service, but could never identify the issue. He was pissed about the issue and Hyundai being unable to clarify it, so he posted in several Korean sites about the issue. To backup his claim, he installed several cameras to record whatever happened. The video revealed that 1) he completely removed his foot off the acc pedal, 2) the acc pedal didn't get stuck and came back to its position, and 3) the car was still redlining even with the pedal back.

This became a topic to several Korean magazines and newspapers. One of the major broadcasting companies was about to interview him about the issue. There were speculations that it may be caused by ECU, electronic throttle, or airflow sensor. So, it looks like Hyundai had "private meeting" with him, and he soon came back that he and Hyundai clarified the issue. And he removed all the posts as well as all the videos over the web. Sounds phish, but well, anyway.

Here was what caused the problem according to him. He replaced the front wheels with the smaller sized ones. He didn't mention how small it was, but the rumor has it that 215/45/17 compare to OEM of 225/45/18, so about 5% smaller. Because of that, when he accelerates, VDC recongnized slower rear wheel rotation as slip, so sophicated and advanced VDC opened up the throttle by itself to speed up the rear to match the speed of the front wheel. But since no matter how fast the rear wheels spin, the front wheel spin faster, so VDC opens up more throttle to make rear wheel spin faster, and the front wheel spin even faster, so VDC opens up more throttle again, and so on and on. That's what caused the unintended accelaration accoring to Hyundai.

Some people say it's possible, while the most people say it's BS and Hyundai is trying to hide the real problem, especially considering his sudden attitude change after the meeting with Hyundai people. What you guys think? Is it techincally sound cause?

 

[SpatiallyAware]

At this point it would be really REALLY stupid for them to attempt to cover anything up in any way, shape, or form. It would mean death to the company, imo, since they have such a young reputation.


It sounds plausible to me, but a huge problem programming-wise. What happens if you use a spare? They have to account for people changing wheels of oddball sizes.

 

[sdifox]

That would be mightily stupid programmer if that is the case.

 

[HannibalX]

Physical throttle linkage FTW. While we're at it I'll stick with my physical shifter linkage as well, and engine powered hydraulic power steering.

 

[KDKPSJ]

I agree it's programming disaster if it really is an issue of VDC with wheel rotation. But I also suspect it could be electronic throttle Hyundai started to use, but they just don't want to admit it unless US government steps in (lol).

 

[StageLeft]

I guess it sounds plausible. I mean I can see how it would try to chase the front and never catch up, but surely vdc is smarter than this? What if your rear tires are worn and the same size as the front (are they?) and you put them on the front and now the rear have a slightly wider diameter, what happens then?

Good job on him recording with cameras, though.

 

[PricklyPete]

Where was this story recorded? It sounds interesting...and possibly plausible...but also sounds like a nice story unless there is a credible source.

 

[KDKPSJ]

Where was this story recorded? It sounds interesting...and possibly plausible...but also sounds like a nice story unless there is a credible source.

Well, the original story and discussions were in Korean, but all of them including video record were deleted by the author as far as I know. While there are still lots of discussions going on in Korean sites, I doubt any Korean media will report this since it's officially closed case.. Even though it's still controversial.

 

[JDub02]

i guess this is what happens when you outsource programmers.

 

[AMCRambler]

What is VDC? Is it Hyundai's form of traction control?

If so, why would you ever give a computer the ability to increase throttle position to adjust for slipping wheels for traction control???? This makes no sense. Every traction control system I've ever read about cuts the throttle to counter slip and it only affects the wheels that drive the car. So a two wheel drive car with rear wheel drive that has front wheels spinning faster than the rears traction control should do nothing. If it's two wheel drive with front wheel drive, and the fronts spin faster than the rears, it should cut throttle to stop the spinning of the wheels. All wheel drive would work the same way except it would cut power to all the wheels or possibly to the one wheel slipping.

To my knowledge the only time a computer would increase the throttle position when driving is in cruise control. There's no time I could think of where it would be advantageous to increase the throttle position to counter a skid and programming a computer to do it would be just as bad as a driving doing it.

Am I wrong?

 

[KDKPSJ]

What is VDC? Is it Hyundai's form of traction control?

If so, why would you ever give a computer the ability to increase throttle position to adjust for slipping wheels for traction control???? This makes no sense. Every traction control system I've ever read about cuts the throttle to counter slip and it only affects the wheels that drive the car. So a two wheel drive car with rear wheel drive that has front wheels spinning faster than the rears traction control should do nothing. If it's two wheel drive with front wheel drive, and the fronts spin faster than the rears, it should cut throttle to stop the spinning of the wheels. All wheel drive would work the same way except it would cut power to all the wheels or possibly to the one wheel slipping.

To my knowledge the only time a computer would increase the throttle position when driving is in cruise control. There's no time I could think of where it would be advantageous to increase the throttle position to counter a skid and programming a computer to do it would be just as bad as a driving doing it.

Am I wrong?

Yes, VDC = Vehicle Dynamic Control.

And that's what my understanding of the correct traction control would do. But there was someone claiming that Hyundai's new VDC has an ability to speed up the wheel speed in the situation described in OP. They call it "Positive Feedback" as they rev-up to speed up the slower wheel, rather than use break to speed down the faster wheel.

Glad you mentioned cruise control. Funny, but cruise control is not available for Korea ver. Genesis Coupe People make a joke that it's hidden cruise control that even the driver can't control. lol.

 

[PhoKingGuy]

Yes, VDC = Vehicle Dynamic Control.

And that's what my understanding of the correct traction control would do. But there was someone claiming that Hyundai's new VDC has an ability to speed up the wheel speed in the situation described in OP. They call it "Positive Feedback" as they rev-up to speed up the slower wheel, rather than use break to speed down the faster wheel.

Glad you mentioned cruise control. Funny, but cruise control is not available for Korea ver. Genesis Coupe People make a joke that it's hidden cruise control that even the driver can't control. lol.

??????????????????? a 10k Hyundai has cruise control, why wouldnt this?

 

[KDKPSJ]

??????????????????? a 10k Hyundai has cruise control, why wouldnt this?

Hyundai's excuse: Due to the street condition of Korea, you may not use cruise control anyway. So, we decided not to put it to save us some money.

 

[halik]

I call big time shens on Genesis having a torque vectoring electronic differential

edit:
Horseshit as suspected. Genesis comes with a torsen diff, which means it will only change to the RWD bias if your front wheels are spinning faster than the rears (more power to the back wheels). If you keep driving it, you'll burn out the center diff.

 

[PhoKingGuy]

Hyundai's excuse: Due to the street condition of Korea, you may not use cruise control anyway. So, we decided not to put it to save us some money.

seriously? Cruise control is illegal? Or is it that the roads suck so much you cant use it?

 

[LTC8K6]

Shens...

 

[thescreensavers]

I call big time shens on Genesis having a torque vectoring electronic differential

edit:
Horseshit as suspected. Genesis comes with a torsen diff, which means it will only change to the RWD bias if your front wheels are spinning faster than the rears (more power to the back wheels). If you keep driving it, you'll burn out the center diff.

The Gen coupe is only RWD, whats this changing to RWD bias you talking about.

And I forgot do all of them come with that Torson diff? I thought it was the track models only.

 

[AdamK47]

My cars have furiously wild intended acceleration. It's a problem that happens often.

 

[videogames101]

My cars have furiously wild intended acceleration. It's a problem that happens often.

quite.

 

[AdamK47]

quite.

Intensifier not needed.

 

[halik]

The Gen coupe is only RWD, whats this changing to RWD bias you talking about.

And I forgot do all of them come with that Torson diff? I thought it was the track models only.

Oh whoops, read the wikipedia article as AWD with torsen in the middle. That's completely stupid then; on RWD cars front wheels rotate independently of the rear (in turns, slippery conditions, acceleration, braking etc. ).

What the BS story is implying is that
a) the slower rotating rear wheels are slipping (wrong, the slower wheels are the ones with traction under acceleration)

b) opening throttle to compensate for lack of traction (self explainatory why thats's wrong).

The only time the slower spinning wheel is the one that's losing traction is under braking; don't think you fix that by opening throttle either.

 

[AMCRambler]

Oh whoops, read the wikipedia article as AWD with torsen in the middle. That's completely stupid then; on RWD cars front wheels rotate independently of the rear (in turns, slippery conditions, acceleration, braking etc. ). What the BS story is implying is that a) slower rotation rear wheel is slip (wrong, the slower wheels are the ones with traction under acceleration) b) opens throttle to compensate for lack of traction (self explainatory why thats's wrong).

The only time the slower spinning wheel is the one that's losing traction is under braking; don't think you fix that by opening throttle.

I still don't think that you would ever advance the throttle in a low traction situation whether computer controlled or human controlled. The last thing you'd want to do is accelerate into a skid. Unless you're that drifting guy that whipped his Skyline through the hairpin backwards in that Youtube vid. Pretty sure most Hyundai Genesis drivers aren't that guy.

 

[franksta]

Physical throttle linkage FTW. While we're at it I'll stick with my physical shifter linkage as well, and engine powered hydraulic power steering.

This plus a regular cut metal key for me.

 

[BlahBlahYouToo]

they should just blame toyota.

 

[Kelvrick]

I still don't think that you would ever advance the throttle in a low traction situation whether computer controlled or human controlled. The last thing you'd want to do is accelerate into a skid. Unless you're that drifting guy that whipped his Skyline through the hairpin backwards in that Youtube vid. Pretty sure most Hyundai Genesis drivers aren't that guy.

Link?