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

[OneFunGenesis]

^ I have had this happen in a different way. When this happens to me, the car slams into gear, then hesitates while it decides if the gear is right. Then takes off like bat from hell

 

[SoCalGen]

^ I have had this happen in a different way. When this happens to me, the car slams into gear, then hesitates while it decides if the gear is right. Then takes off like bat from hell

Mine hasn't slammed but maybe cause I don't have the torque of your 4.6.

 

[RN2X]

I just removed the magnet and replaced the little clip. I took a little spin around the block and I was able to tell a significant difference in lag time. It was still there but it seems to be much shorter. I will get it back out this evening and run it thru a few different situations and see how it feels.

 

[sluggo]

I'd been driving around on a "half-way" mod for some time (piece of 1/4" felt between the stock magnets) and was reasonably happy with the off-idle feel. Least week I took off the felt and reversed the magnet in the flappy door so it never closes and sits at about 1" open. I'm much happier with the off-idle pedal now. Accelerating from 0-20 feels like a 330 hp car instead of a 4-cylinder with a confused CVT. Not going back, and will continue to look for mods to improve throttle response further.

 

[rhubarb9999]

I started to notice the lag getting worse on my 4.6. Sure enough, I opened the air filter and the little felt pads I had put in had compressed and the flap was almost completely closed. I removed the whole flap this time and performance is back to the 'new' normal.

 

[LandoAWD]

So, I have been quietly reading about the quirks and joys of the "new" car choice, and had found myself wondering about the "lag" from a dead-stop/low RPM accels. I removed my entire flapper last night, and have it ready to go back in with the magnet mods should I so need to, and can say that I saw marked improvement on the drive to work today.
Voted in the poll.

 

[craigt]

I have further modified the flapper and removed the magnet from the flapping part. There is a improvement in every day driving, but there is still a lag when slowing down (40 to 5) and hitting the gas to merge into traffic.

Better, but still not ideal.

 

[daviderle]

I have further modified the flapper and removed the magnet from the flapping part. There is a improvement in every day driving, but there is still a lag when slowing down (40 to 5) and hitting the gas to merge into traffic.

Better, but still not ideal.

Craig, can you do me a favor and try the following:

Ideally on an empty road, as you are slowing down, while your foot off the accelerator, momentarily go into manual mode, go one gear down (-), then go back into auto and try to simulate merging into traffic / punch it.

If that has no impact, can you try different combinations, example a little throttle while changing gears, or try leaving it in 'sports' mode and see if that helps the lag.

I now have enough understanding and data of how the 8sp differs from the ZF behavior / programing (for both 4.6 and the R-spec), but unfortunately I do not have access to a 3.8 to be able study it to that level of detail.

The 8sp programing can be adjusted with enough 'manual' intervention (supported by collected data), I found driving around 200 miles using manumatic/sport mode and exclusively changing gears manually has resulted in a significant gear changes improvement. (But should you try to replicate this process, be forewarned you MPG will suffer greatly during that period).

for example after my transmission was 'trained' to my driving preferences, if I let off the gas at say 50mph, the rpm never drops down bellow 1500rpm, the net result is if I punch it at any time the R-Spec simply takes off within 500ms, if I hold the stick down in 'sports' mode while I punch it, the delay is around 350ms (but sometimes results in a wheel spin and the ESC engaging if the gearbox is in 2nd or 1st gear).

I never needed to do anything like this in the 4.6/ZF as it has always been a predictable 650ms delay.

Again, none of this may work for you so YMMV, but it would be of great interest to see if any of these methods will work on 3.8/8sp..

 

[craigt]

I will try to do this and get back to this thread, though I'm not sure when I'll be able to find an open road to be safe.

If I leave it in manual mode, there really isn't a lag because there isn't any gear hunting. Throttle response is as close to immediate as drive by wire can be.

Question about program training: You mention ~200 miles to train. Does the training eventually "wear off" over time if I then leave it in full auto for the next 2,000 miles? Or does it retain the training virtually forever?

 

[daviderle]

I will try to do this and get back to this thread, though I'm not sure when I'll be able to find an open road to be safe.

If I leave it in manual mode, there really isn't a lag because there isn't any gear hunting. Throttle response is as close to immediate as drive by wire can be.

Question about program training: You mention ~200 miles to train. Does the training eventually "wear off" over time if I then leave it in full auto for the next 2,000 miles? Or does it retain the training virtually forever?

Please be safe first and formost!

As far as I can tell (without having access to the trasmition CPU, indeed, it has its own encrypted ECU!), the trasmition continuly adapts to your driving style and some parameters are avraged out over the last 200 miles, the way I learned to keep both the trasmition and engine 'tuned' to my driving style, is every 50 miles or so, is to drive the car like I stole it for at least 5 miles or so in manumatic/sports mode. This procedure seems to do the trick for me on the R-Spec/8sp.

As a side note, the 4.6/ZF requires less intervesion in almost 7 years/55k imiles of driving her... Go figure!

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[LandoAWD]

I'd love for someone to crack the TCU to enable selectable full line pressure shifts. That said, for a sedan, the sports mode isn't bad.
I was very close to buying an E63 AMG, and despite all the refinement smooshed together with raw power, it still had worse street manners than this 8spd. Go figure.

 

[amartz]

is every 50 miles or so, is to drive the car like I stole it for at least 5 miles or so

+1

 

[jlandry]

I just took mine out by removing the screw and pulls right out as far as response I like it better no hesitation at minimum throttle or full throttle

 

[DRS]

I just took mine out by removing the screw and pulls right out as far as response I like it better no hesitation at minimum throttle or full throttle

Let us know if it affects the mileage.. Some debate and experiences in here doing this lowers mileage.. I would like to know.. I am, suspecting that maybe those who experience lower MPG, might be taking advantage with their slight lead foot, the better response..

 

[amartz]

Let us know if it affects the mileage.. Some debate and experiences in here doing this lowers mileage.. I would like to know.. I am, suspecting that maybe those who experience lower MPG, might be taking advantage with their slight lead foot, the better response..

Of *course* it affects the mileage. It feels so *Good* now. May I have another, sir!!

 

[SoCalGen]

I'm switching back to running the flapper door and full magnet. I really think it's for the best. I never noticed much (if any) improvement. It seems to have hurt my mileage and it didn't solve the real issue in my mind of the 8spd tranny not getting back to first quick enough. My hesitation problems ALL seem transmission related not air/fuel mix related.

 

[PMCErnie]

30mph to 0mph or maybe 30mph down to a rolling 1-3mph then flooring it. There's always at least a 2 second delay if I go from 30-0 hard on the brakes. The car acts like it's confused.

I'm sure it would do the same thing if I was going faster though. The computer must be programmed to assume that someone who's stopping quick isn't going to take off fast so it lets the transmission leisurely shift down to first.

The fix is not to floor it. Instead, apply gradually increasing pressure to the gas pedal.

 

[SoCalGen]

The fix is not to floor it. Instead, apply gradually increasing pressure to the gas pedal.

Do you know how hard it is NOT to floor it in a Genesis?!?!?!?

 

[amartz]

Do you know how hard it is NOT to floor it in a Genesis?!?!?!?

Actually, that's what I liked about the fix. I get the grin on my face without having to floor it. Half throttle works very nicely most times.

 

[Potty_Pants]

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