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Dead pedal / “Engine falls flat” potential fix..

In order to assist others who are experiencing this issue, please contribute:


  • Total voters
    63

dmitriylm

Registered Member
587
1
0
So I've been off the forums for 2+ years...

and i come back and find this thread at the top....

Dead pedal delay has always been a problem with my car/the car since I've test drove it. Quite frankly how the engine & trans has turned me off of V8s favoring 4 or 6 turbo manual. btw itching for the Abarth... but waiting for next gen.. 5 sp key start is so 1989. too close to my first car.

I removed the flapper completely and tested a couple of days later as mentioned in the above post. in order for me to accelerate I needed to full throttle then back off the throttle for driving. now all i need to do is 1/4 1/2 anything and the response is near immediate (exactly as desired).

I've read thru the pages of msgs and to be honest didnt take a close look at where the piping is routed. Do you think the pupose of the flap is to keep water from getting sucked up ?

amazed this was all thats required !!! thank you !

now if you can just figure out why the manumatic is slow to shift ;)
The manumatic gear change is about what I'd expect. It's a lot faster than the gear change I had in my 2003 Infiniti G35 and no worse than what was in my 2007 BMW 530i.
 

Potty_Pants

Been here awhile...
475
1
0
2005 g35... way log ago but feels the same delay.
however automatic shifting from gear to gear is faster.

vs E90 2007 +335 auto... no comparision that (while mine was a stick) the loaners were autos
and right there almost no delay. bmw had to dial the trans down alittle because of how
jerky quick shifts occurred.


back on topic.

I've had a few more days to work it and solid ! I cant wait to see if TCS/DSC handles better.
 

Hijinx

Registered Member
10
0
1
I'm going to do some experimenting this weekend. I've read all the post on this thread and I've come up with some theories. Some of this is common sense

Flapper Completely Removed: If you remove the flapper you will get much better throttle response. I agree with that, but you will most likely see a small decrease in gas mileage. Thats because the flapper does help steady the gas mileage. I've been monitoring this closely for a week now. I do mixed highway & city driving. I average about 25-27mpg. The flapper tries to create a smoother acceleration instead of the instant throttle response w/o flapper. With instant throttle you're going to see a decrease in MPG.

I'm going to try the flapless method and see what happens.
I think this hits the nail on the head...the flapper is probably there for mileage purposes. Period. End. Stop.

I took the assembly out today and the change in throttle response was instant and very real.
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kf4zra

Registered Member
299
0
16
Tampa, FL
I left the flapper but removed the magnets today. The initial acceleration from a stop has improved a lot, cant feel any difference after I am already rolling though.

Fairly certain that most of the delay in pressing the gas pedal and the car moving is transmission related.
 

scottdk

Registered Member
3,203
30
48
Minnesota
Weird^ Wouldn't the car have the flapper removed if the car had better throttle response or more power from the factory??????? C'mon, a butt dyno is not applicable here. Placebo? I put R Spec wheels on my Genesis and now it's faster. Because I think it should be faster. I've had the flapper....then removed it for a couple of years, then put the flapper back on. No difference. This car is 2 tons.
 

amartz

Registered Member
1,204
7
38
Jacksonville, FL
Weird^ Wouldn't the car have the flapper removed if the car had better throttle response or more power from the factory??????? C'mon, a butt dyno is not applicable here. Placebo? I put R Spec wheels on my Genesis and now it's faster. Because I think it should be faster. I've had the flapper....then removed it for a couple of years, then put the flapper back on. No difference. This car is 2 tons.
I'm starting to think this mod has more effect for a V6 like mine than a V8, where the difference seems less pronounced. As far as your snide "butt dyno" comments, the gentleman that started this whole modification was measuring results thru an interface to his laptop, and had actual timings, to the tenth of a second, before and after. No "butt dyno" involved. Specifically, he was measuring fuel flow, and how long it took the flow to ramp up, as a measure of demand from the engine. And the point wasn't that the car was faster, it was that the car was fast *sooner*, like a good two seconds sooner in some circumstances.
 

kf4zra

Registered Member
299
0
16
Tampa, FL
Weird^ Wouldn't the car have the flapper removed if the car had better throttle response or more power from the factory??????? C'mon, a butt dyno is not applicable here. Placebo? I put R Spec wheels on my Genesis and now it's faster. Because I think it should be faster. I've had the flapper....then removed it for a couple of years, then put the flapper back on. No difference. This car is 2 tons.
I was only sharing my experience. My experience concurs with the OP's post with numbers showing fuel flow rate increasing sooner. It does not make more power, nor did I ever say it did. For you to think that this will make more power than the engine is capable of, shows your lack of understanding of how an engine works. This mod only allows the application of power that the engine was always capable of producing to be accessed sooner.

Mine is a 2013 r-spec so I cannot comment on how a smaller, non DI engine will act to this mod, nor did I ever claim to. I related my own personal experience. I PERSONALLY have never had the traction control kick on as much off the line since I pulled the magnets.

I am certain that the flap is in there to keep the engine from drawing as much air too soon to improve mileage. Why else would they restrict intake air with the option to bypass it. I am thinking that it was intended to conserve fuel in stop and go traffic situations.

The car is designed to be a comfortable car that is peppy, it was not completely designed around performance. People that want this car are buying comfort with the ability to have a little fun if they want. If it were designed around performance only, it would have a much larger factory cold air intake, no flap, much larger exhaust, weigh at least 1000lb less, have a stick shift, and get less MPG.

The only thing stopping the flap from opening is engine vacuum which would increase after the throttle body is opened. To build the required amount of vacuum to overcome the magnets takes time. If there is no resistance from defeating the magnets, the RPMs can increase sooner. That is known as faster throttle response. I have only seen an improvement off the line because the transmission is in the proper gear. From any rolling speed, I have not seen any improvement because the transmission is too slow in selecting the proper gear for downshifting. By your logic, why did they install a slow shifting transmission in the car? Here is your answer, by keeping the transmission in a higher gear, the engine can run at lower rpms saving fuel. The slower shifts are a result of the software in the transmission keeping the power train from taking too much of a beating since Hyundai has to warranty it for 100k mi.

I am assuming that you have never seen how tiny the air intake is with the flap closed? Do you really think that if they didn't have that flap there that your car could breathe properly at full RPM through the 1" intake that is there? Block off your flap and tell us how great your car runs.

Have fun trolling people's posts that are simply trying to relay info to others.

I have no more time for you.
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Sal Collaziano

Genesis Motors Forum
Staff member
5,917
248
63
Palm Beach, Florida
Genesis Model Type
2G Genesis Sedan (2015-2016)
Please try to refrain from personal insults, guys. Attack ideas, not people. I know it's not always easy but I very much want this to be a friendly community. I'm not pointing any fingers because I haven't followed this discussion very closely and cannot at this time...
 

Ram Air

Registered Member
60
0
6
It's been eleven months since I last posted tests (simple ones) regarding the Dead Pedal a.k.a.Flapper Door issue..................... and the debate still continues.
Members:
1) My flapper door has been off since Dec./2014. In over 10000 mile of record keeping mileage has not been affected one bit.
2) Throttle response has been improved in part throttle situations.
3) Transmission downshifting is still tardy.
4) There is a slight increase in air induction noise when feeding in throttle to less than WOT (wide open throttle).
That's it! Nothing more....................... nothing less.
My flapper door is gathering dust! (And so should this thread )
 
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GennyBird

Hasn't posted much yet...
3
0
0
Not to resurrect an old thread, but I saw many more conclusive results for the 5.0 engine. Anyone know whether this worked on the tau 4.6 with the ZF 6 speed from a 2009 sedan? I do feel as if something is holding the car back at lower speeds, but once on the highway it's much more responsive. I'm mechanically challenged, so I'd probably do this with a friend. I don't want to ask for his help without evidence that it will work. Thanks a lot.

Edit: I always assumed it was a transmission issue as SoCal suggested, but I'd be happy to get a little more out of the car.
 

daviderle

Registered Member
770
102
43
Genesis Model Type
2G Genesis Sedan (2015-2016)
Not to resurrect an old thread, but I saw many more conclusive results for the 5.0 engine. Anyone know whether this worked on the tau 4.6 with the ZF 6 speed from a 2009 sedan? I do feel as if something is holding the car back at lower speeds, but once on the highway it's much more responsive. I'm mechanically challenged, so I'd probably do this with a friend. I don't want to ask for his help without evidence that it will work. Thanks a lot.

Edit: I always assumed it was a transmission issue as SoCal suggested, but I'd be happy to get a little more out of the car.
I have both the 4.6 and 5.0 , I have never been able to create the 'dead pedal' issue on the 4.6!

Few questions;

What is the mileage on the car?
Did you always had this issue? or has been getting worse over time?
Do you drive the car 'hard'? or do you take it easy?

Can you also add some more clarity around "something is holding the car back at lower speeds"? examples would be;

- Accelerating from 10-30mph is slow.
- The car does not accelerate as it should from a dead stop (delayed), when I floor it.
- There is a delay in acceleration in a specific RPM range, at this speed.
- The vehicle does not select the right gear, when I put my foot down.
- etc

That way we are better able to determine if any of these suggested methods will have any impact on your particular issue(s)..
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technopeasant

Registered Member
38
0
0
PNW
Kinda of anecdotal, but I had a 2012 V6 for 3 years that would reliably invoke the "death pause from rolling stop" when trans was in auto-mode.
Have had a G1 2014 R-spec for 6 weeks now and it simply wont do the death pause.
 
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GennyBird

Hasn't posted much yet...
3
0
0
Thanks for getting back to me, honestly I doubt i have a dead pedal based on what you're saying. I probably just with the car was faster. It's usually at low speeds. I do tend to drive the car a bit hard but rarely do I actually floor it unless I'm already at speed. Milage is about 88k. I am the second owner you could say, my dad upgraded & I got it with about 70k on it. He drove it pretty conservatively.
 

daviderle

Registered Member
770
102
43
Genesis Model Type
2G Genesis Sedan (2015-2016)
Thanks for getting back to me, honestly I doubt i have a dead pedal based on what you're saying. I probably just with the car was faster. It's usually at low speeds. I do tend to drive the car a bit hard but rarely do I actually floor it unless I'm already at speed. Milage is about 88k. I am the second owner you could say, my dad upgraded & I got it with about 70k on it. He drove it pretty conservatively.
I see and agree with you...

Few things you can try, fill up with top tear premium gas (think shell, BP etc) as well as adding fuel system cleaner (ex: http://www.autozone.com/fuel-and-engine-cleaners-additives/fuel-additive-and-cleaner/techron-20-oz-fuel-system-cleaner/27796/?_requestid=5883729) and to drive the car for 200 miles or so in manual mode, letting the engine rev up a bit (between 2k and at least 4.5k RPMs) this will will do several things, including getting rid off any carbon deposits that might have built up over the years as well as re training the transmission to stay in lower gears more often than not and therefore, you may notice a an improvement when accelerating at lower speed...

But these are just few suggestions and YMMV....

[EDIT] my 2009 4.6 with 60k miles, will down shift to third gear, when I press the gas halfway as I am doing around 50mph, second gear when I am doing 30mph, a clean engine and well trained transmission should show this level of driving 'engagement'...
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daviderle

Registered Member
770
102
43
Genesis Model Type
2G Genesis Sedan (2015-2016)
Yes, reportatly slightly worse MPG as well as additional cabin noise.
But YMMV (literally) :D
 

Ram Air

Registered Member
60
0
6
No reason not to remove it. I've had mine off for well over a year now. I always keep a record of my fuel economy since buying the car new. Gas mileage will return to normal as soon as you forget that you've removed it................ in other words, as soon as you resume driving normally.
Daviderle is right about the cabin noise (induction roar ) being slightly increased.
 

CRSpec

Registered Member
34
0
0
Tampa
No reason not to remove it. I've had mine off for well over a year now. I always keep a record of my fuel economy since buying the car new. Gas mileage will return to normal as soon as you forget that you've removed it................ in other words, as soon as you resume driving normally.
Daviderle is right about the cabin noise (induction roar ) being slightly increased.
That's normally how it goes with enhancements :D

Whats your MPG's normally in the city, Ive been able to average 19 with is nice. Ill be doing this soon, I have a K&N filter coming in this week.
 
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