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

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


  • Total voters
    59

daviderle

Registered Member
635
34
28
I have been trying to experience this issue first hand for a week, I am happy to report that I was able to it create twice, the first time I did not have logging enabled for the OBDII, but fortunately I was able to recreate it the second time around while I had the raw data logging enabled.

After studying the data late last night, I think I may have found one of the root causes that contributes to this phenomenon.

By looking at fuel flow, Throttle position, MAF (Mass-air Flow Sensor), RPM I determined there a delay of approximately after 1.65 but before 1.87 seconds when the RPM begins to rapidly to pickup.

The sequence of events is as follows:

0.00 sec Throttle position change
0.15 sec Fuel flow increases
0.33 sec Fuel flow reduced (almost idle)
1.37 sec Fuel flow increases very slowly
1.49 sec RPM begins to rise.
1.86 sec MAF reading changes significantly
1.86 sec Fuel flow increases significantly

Without boring everyone to death with the gory details, suffice to say I suspect the engine is being chocked under this condition!

So this morning I wracked my brain as to what might cause this and remembered some old threads were we discussed removing the ‘flapper’ located in air filter unit.

The MAF main impact variation is the air flow door (=flapper) position, is only opened when there is sufficient vacuum to overcome the magnet force keeping it in the closed position. To my surprise the magnet in the R-Spec is much stronger than found in my other car (2009 4.6).

To cut a long story short, I found some 1/2” inch Self-Adhesive Anti-Skid pad (the ones used to under objects so they do not scratch a glass table), lying around to experiment with by placing it between the magnet and the main air intake door to weaken the magnet effect, with following results:

0.0 sec Throttle position change
0.15 sec Fuel flow changes
0.23 sec RPM begins to rise up
0.36 sec MAF reading changes significantly
0.47 sec Fuel flow increases significantly

I have done two runs with at least 13 different attempts to recreate the issue without any success :)

I will keep experimenting, but for everyone else that has been suffering from this issue, it will be interesting to validate if this $2 mod can have a positive impact.

[EDIT instructions]

- Open the hood
- The air filter unit is located on the passenger side and to the front of the vehicle.
- Remove the two clips securing at the back of the unit.
- Gently loosen up the top and remove away from the unit.
- Remove the air filter
- Gently lift the large air intake door at the bottom of the unit, from the left where the magnet located.
- While holding the door open with one hand, firmly install Self-adhesive Anti-Skid pad on top of the lower magnet as shown below.

Sorry for the blurry pictures:

IMG_closed_mafc.jpg
IMG_1670_open_mafc.jpg

As a reminder, any modification made to your vehicle may have an impact on your warranty.
 
Last edited:

bobby181

Hasn't posted much yet...
5
0
0
I have a 2012 V6. That was the first thing I took off when I did my first oil change after getting my Gen. It still have issue with big delay's. I love the look of the Gen, but the programing is JUNK on this car. I am a very aggressive driver and this is killing me. I also am having issue with my trans slipping and hard sifts for 1-2 2-3 4-5. It will rev up 2000-4000 when slipping. Hyundai really needs to fix the programing for the driver by wire, and the ESC to give you some more play. Before it kicks in and to be able to turn it of the ESC 100%. This car is so nanny controlled it is not funny. I miss my JAG and BMW.

We need to find a fix for this, or we need to start writing to Hyundai or something.
 

Gunkk

Registered Member
SUSTAINING MEMBER
1,304
34
48
Florida
Genesis Model Type
1G Genesis Sedan (2009-2014)
Daviderle - This is really great work!!!!

Questions...
Are the 2009 and 2012 flappers mechanically the same?
And then next question, are they different Hyundai part numbers.

If yes to both, then anyone with this issue s/b able to swap out the 2012 overly-strong-magnet-flapper with a 2009 less-strong-magnet-flapper.
______________________________
 
Last edited:

daviderle

Registered Member
635
34
28
Daviderle - This is really great work!!!!

Questions...
Are the 2009 and 2012 flappers mechanically the same?
And then next question, are they different Hyundai part numbers.

If yes to both, then anyone with this issue s/b able to swap out the 2012 overly-strong-magnet-flapper with a 2009 less-strong-magnet-flapper.
Sorry for the delay...

The 2009 4.6 and 2013 R-Spec flappers do appear to be mechanically the same with 4.5" from top to bottom.

I think I can try that idea and see if that works, but such an endeavor would have to wait until I have few more hours to play, perhaps one weekend, so I am able to take additional data...
 

daviderle

Registered Member
635
34
28
I have a 2012 V6. That was the first thing I took off when I did my first oil change after getting my Gen. It still have issue with big delay's. I love the look of the Gen, but the programing is JUNK on this car. I am a very aggressive driver and this is killing me. I also am having issue with my trans slipping and hard sifts for 1-2 2-3 4-5. It will rev up 2000-4000 when slipping. Hyundai really needs to fix the programing for the driver by wire, and the ESC to give you some more play. Before it kicks in and to be able to turn it of the ESC 100%. This car is so nanny controlled it is not funny. I miss my JAG and BMW.

We need to find a fix for this, or we need to start writing to Hyundai or something.
Bobby181, what you are describing are three distinct issues, which are different from the case I was able to recreate.

Starting with the ESC disable, there are ways to disable it on the V8, not sure if you have tried to remove the ESC/ESP fuse on the V6 to see if it works for you?

As far as the gearbox slipping, I have not experienced that particular issue with the 2009 4.6 ZF nor with the 8 Speed R-Spec, if you can recreate the slipping issue, the dealer should at least be able to check the transmission fluid and get that changed if possible, since you mentioned that you push the car to the limit more often than not.

While I agree that the ECU programming can be considered a little rough around the edges when the Genesis is pushed hard, I would personally not describe it as 'JUNK'.

For what its worth, the behavior of the Genesis ECU is rather similar to what I experienced driving a Lamborghini Murcielago LP-640 2011, in Las Vegas (http://www.exoticsracing.com/) several years back, at which point the instructor taught me how to drive the 'Bull' properly, which simply to begin pressing the accelerator by the letter "O", say "One Mississippi" and only hit the floor by the time I got to "i", by the Sixth lap I was able to hit 137 mph on the 1200 feet strait run!
Simply put it was the most exhilarating and mentally deranged car I have ever driven (thus far :D)..

The Ferrari F430 F1 only required saying "One" which was marvelous, while the Nissan GT-R acceleration/handling was simply sublime, I just punched it and 'Godzilla' did the rest of the work for me..

In summation, it is my humble opinion that a good (racing ;)) driver would know the breaking point of their ride and then tries his/her best to push it right to the edge, but not past the red line... but that is just my two cents...

At the end of the day, regardless of the trim, most agree that the Genesis is more of a cruiser, than a thoroughbread sports sedan.
 
Last edited:

kman

Registered Member
99
0
0
Thank you for doing this and I hope it works. Have you been able to introduce this lag again? Not to long ago my car made me look like a jackass when turning left, rather than taking off when I pressed the accelerator it waited 1-2 seconds and then launched off coming very close to the car that was approaching from ahead. It was close enough to an accident that my passenger starting calling out 'Jesus!', but even that didn't eliminate the lag:)


I have been trying to experience this issue first hand for a week, I am happy to report that I was able to it create twice, the first time I did not have logging enabled for the OBDII, but fortunately I was able to recreate it the second time around while I had the raw data logging enabled.

After studying the data late last night, I think I may have found one of the root causes that contributes to this phenomenon.

By looking at fuel flow, Throttle position, MAF (Mass-air Flow Sensor), RPM I determined there a delay of approximately after 1.65 but before 1.87 seconds when the RPM begins to rapidly to pickup.

The sequence of events is as follows:

0.00 sec Throttle position change
0.15 sec Fuel flow increases
0.33 sec Fuel flow reduced (almost idle)
1.37 sec Fuel flow increases very slowly
1.49 sec RPM begins to rise.
1.86 sec MAF reading changes significantly
1.86 sec Fuel flow increases significantly

Without boring everyone to death with the gory details, suffice to say I suspect the engine is being chocked under this condition!

So this morning I wracked my brain as to what might cause this and remembered some old threads were we discussed removing the ‘flapper’ located in air filter unit.

The MAF main impact variation is the air flow door (=flapper) position, is only opened when there is sufficient vacuum to overcome the magnet force keeping it in the closed position. To my surprise the magnet in the R-Spec is much stronger than found in my other car (2009 4.6).

To cut a long story short, I found some 1/2” inch Self-Adhesive Anti-Skid pad (the ones used to under objects so they do not scratch a glass table), lying around to experiment with by placing it between the magnet and the main air intake door to weaken the magnet effect, with following results:

0.0 sec Throttle position change
0.15 sec Fuel flow changes
0.23 sec RPM begins to rise up
0.36 sec MAF reading changes significantly
0.47 sec Fuel flow increases significantly

I have done two runs with at least 13 different attempts to recreate the issue without any success :)

I will keep experimenting, but for everyone else that has been suffering from this issue, it will be interesting to validate if this $2 mod can have a positive impact.

[EDIT instructions]

- Open the hood
- The air filter unit is located on the passenger side and to the front of the vehicle.
- Remove the two clips securing at the back of the unit.
- Gently loosen up the top and remove away from the unit.
- Remove the air filter
- Gently lift the large air intake door at the bottom of the unit, from the left where the magnet located.
- While holding the door open with one hand, firmly install Self-adhesive Anti-Skid pad on top of the lower magnet as shown below.

Sorry for the blurry pictures:

View attachment 3832
View attachment 3833

As a reminder, any modification made to your vehicle may have an impact on your warranty.
 

amartz

Registered Member
1,203
5
0
Jacksonville, FL
I have a 2012 V6. That was the first thing I took off when I did my first oil change after getting my Gen. It still have issue with big delay's. I love the look of the Gen, but the programing is JUNK on this car. I am a very aggressive driver and this is killing me. I also am having issue with my trans slipping and hard sifts for 1-2 2-3 4-5. It will rev up 2000-4000 when slipping. Hyundai really needs to fix the programing for the driver by wire, and the ESC to give you some more play. Before it kicks in and to be able to turn it of the ESC 100%. This car is so nanny controlled it is not funny. I miss my JAG and BMW.

We need to find a fix for this, or we need to start writing to Hyundai or something.
I'm going to have to try the tape when I get a chance! The hard shifts and revs ring a bell with me. I have a 2012 3.8 sedan, and around 35K it started shifting like that. Never predictable, but most likely to happen between the 2-3 upshift and especially the 4-5 upshift. It would turn loose the lower gear, and delay grabbing the next gear. Occaisionally I'd see the tack jump close to 1k between gears. The dealer tried to fix it by clearing the tranny memory, but that just made it worse. Eventually, they wound up replacing the tranny, fortunately under warranty!
______________________________
 

zielritter

Been here awhile...
832
4
0
Union, KY
Starting with the ESC disable, there are ways to disable it on the V8, not sure if you have tried to remove the ESC/ESP fuse on the V6 to see if it works for you?
Unfortunately it doesn't work for the V6 (at least the 12+). I followed the procedures that worked for the V8 and even experimented with different fuses and step ordering to no avail.

That being said, I guess this is one of the advantages of installing an intake that eliminates the stock air box. I can't remember if the WOT hesitation was worse with the air box, but it's still noticeable, albeit non-intrusive, with my custom intake.
 

amartz

Registered Member
1,203
5
0
Jacksonville, FL
To cut a long story short, I found some 1/2” inch Self-Adhesive Anti-Skid pad (the ones used to under objects so they do not scratch a glass table), lying around to experiment with by placing it between the magnet and the main air intake door to weaken the magnet effect.
I got around to replacing the air filter on my 2012 3.8, and remembering this article, decided to try this. I had some black Gorilla tape laying around, and cut four small rectangles, and stacked them on the bottom of the pipe the intake door closes against. Just judging by feel, I'd say I cut the closing force by about half. So far, I'm happy with the result, it seems much more responsive when first rolling on the throttle. I'll drive it a few more days, just to make sure this isn't a placebo effect, and report back.
 

amartz

Registered Member
1,203
5
0
Jacksonville, FL
After driving it around a week, I'd have to say this "fix" works pretty much as advertised. The times quoted in the original post, 1.86 seconds to 0.47 seconds for the engine to light up, feels just about right. Almost two seconds to respond to the throttle can feel like an eternity when traffic is closing in on you! Less than half a second is *much* better!

One thing I've noticed is that I tend to not hit the throttle nearly as hard when the engine is more responsive to begin with. Also, the downshift on a rolling stop/start is quicker, because the engine is up and going quicker. The dreaded lag from the tranny is not nearly so bad this way. For a couple pieces of gorilla duct tape, it doesn't get much easier or cheaper than this!
______________________________
 

daviderle

Registered Member
635
34
28
After driving it around a week, I'd have to say this "fix" works pretty much as advertised. The times quoted in the original post, 1.86 seconds to 0.47 seconds for the engine to light up, feels just about right. Almost two seconds to respond to the throttle can feel like an eternity when traffic is closing in on you! Less than half a second is *much* better!

One thing I've noticed is that I tend to not hit the throttle nearly as hard when the engine is more responsive to begin with. Also, the downshift on a rolling stop/start is quicker, because the engine is up and going quicker. The dreaded lag from the tranny is not nearly so bad this way. For a couple pieces of gorilla duct tape, it doesn't get much easier or cheaper than this!
Good to hear that it worked for you as well..

It makes the time spend to recreate the issue, study the condition and test a possible solution a worth while effort...
 

daviderle

Registered Member
635
34
28
Since I don't have anything to do today, I'll implement your "mod" and see if it works! ;)
The more testing the better, although I would propose, you implement this mod only if you are able re-create the 'dead pedal' issue.

Also, please keep in mind, that I have not extensively tested and have not gathered any data for this mod while the ESC is (remotely :D) disabled!

So, your observations and input will be greatly appreciated.
______________________________
 

dareckibmw

Supporting Member
SUPPORTING MEMBER
2,051
309
83
Romeoville, IL
Genesis Model Type
Genesis G80 Sport
The ESC remotely disabled thingy works, just like you said it would, although I don't drive my car very often, but so far so good ;)

....I've noticed that - after 2-3 days of raining constantly, it was not responding at all, do to humidity and/or the moisture inside the bay engine (?) but after driving it for ~15 min., it was all good.


Off to Menard's to get anti-skid pads :D
 

Buford T Justice

Registered Member
171
0
16
Wisconsin
Make sure those skid pads won't come loose and get sucked into the engine under heavy throttle. That would suck.
Though it would be pretty funny if Hyundai found multiple Genesis with anti scratch pads deep in the engine.
 

dareckibmw

Supporting Member
SUPPORTING MEMBER
2,051
309
83
Romeoville, IL
Genesis Model Type
Genesis G80 Sport
Make sure those skid pads won't come loose and get sucked into the engine under heavy throttle. That would suck.
Though it would be pretty funny if Hyundai found multiple Genesis with anti scratch pads deep in the engine.
Yeah, I though about it the other day. I think I'm gonna remove it, as I can't see any "improvement". I mean, there probably is, but you won't be able to "see" it or feel it.
 

amartz

Registered Member
1,203
5
0
Jacksonville, FL
Make sure those skid pads won't come loose and get sucked into the engine under heavy throttle. That would suck.
Though it would be pretty funny if Hyundai found multiple Genesis with anti scratch pads deep in the engine.
You don't understand the situation. The tape is upstream of the air filter. The worst that could happen is the tape comes loose and lodges against the air filter. The engine is never in danger.
 
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