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991S PDK throttle hesitation from start

 
Old 07-27-2013, 08:29 PM
  #31  
MrSelfDestruct
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No issues on my 2013 C4S manual. Are folks only noticing this with PDK?
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Old 07-27-2013, 09:58 PM
  #32  
chuckbdc
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My Jan 2012 C2S has not had any hesitation problems from start. I think I can feel variations in response related to the torque curve when getting on it at various speeds, but it does not seem to be a PDK issue.
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Old 07-28-2013, 01:27 AM
  #33  
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Had my service done last week with May PDK software update installed. No change in anything noticeable. Service manager tried other 991S's with PDK and found they all have this issue.

The throttle/acceleration hesitation is a delay. Hit the throttle hard from a stop, jumps 100 rpm from idle, delay, then continues without issue. No throttle hesitation issue when not in gear.

In Normal mode, idle is at 700. Hit throttle, it jumps to 800 rpm, delay, then keeps going.

In Sport and Sport Plus, idles at 800. Hit throttle, it jumps to 900 rpm, delay, then keeps going.
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Old 07-29-2013, 12:51 AM
  #34  
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Originally Posted by CarManDSL View Post
Had my service done last week with May PDK software update installed. No change in anything noticeable. Service manager tried other 991S's with PDK and found they all have this issue.

The throttle/acceleration hesitation is a delay. Hit the throttle hard from a stop, jumps 100 rpm from idle, delay, then continues without issue. No throttle hesitation issue when not in gear.

In Normal mode, idle is at 700. Hit throttle, it jumps to 800 rpm, delay, then keeps going.

In Sport and Sport Plus, idles at 800. Hit throttle, it jumps to 900 rpm, delay, then keeps going.
I think you've described it quite accurately.......now what are the chances that Porsche will come out with a fix? It is obviously affecting quite a few PDK cars both 991 and 981 recently. Is there anything that can be suggested to the owners of these cars to be more proactive?
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Old 07-29-2013, 07:16 AM
  #35  
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I am not certain this is a 'problem', but perhaps it is just the ECU pre-managing the potential wheel-spin issue when accelarating strongly in the lowest gear (as it doesn't happen in the higher ratios).
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Old 07-29-2013, 07:20 PM
  #36  
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Originally Posted by draxa View Post
I am not certain this is a 'problem', but perhaps it is just the ECU pre-managing the potential wheel-spin issue when accelarating strongly in the lowest gear (as it doesn't happen in the higher ratios).
There is no delay with launch control. Not an issue if you hold brake, paddle to N, rev to any rpm above idle, paddle to 1st and drop the brake - kind of launch.

Traction control on or off, no difference in any method of acceleration from a dead stop.

If the ECU is "pre-managing" for about .25 seconds than it is thinking in Neanderthal mode. Something else is at play.
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Old 07-30-2013, 11:16 PM
  #37  
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We used to call this a "neutral drop" back in the say on automatics which was really hard on the transmission. Any reason to think it would be different on PDK?
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Old 07-30-2013, 11:37 PM
  #38  
10 GT3
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Originally Posted by TRAKCAR View Post
Maybe they fix it in the GT3 PDK-S
Not likely. Search the GT3 forum for the video of the pre-production car that they were driving it onto a trailer and it kept stalling. I have a feeling it is intentional for clutch longevity.
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Old 07-31-2013, 12:56 AM
  #39  
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when i was buying my car last summer, the PDK delay was the reason i went with a 7 speed MT. I had a deposit on a car with PDK with sport chrono, and the constant sensation of the car hesitating when i dropped the hammer drove me nuts. To me, it wasn't worth 5 k for the PDK if it hesitated, I can do that for free in my MT. However my wife's 2013 Audi S4 Stronic is a jackrabbit off the line in dynamic mode....
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Old 08-01-2013, 08:11 PM
  #40  
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I have a March 2013 C4S and have been annoyed by the hesitation from standstill. Major issue when I'm looking for a small gap in traffic in main road when I'm trying to join from side street - I need to leave a much bigger gap because of this hesitation!

Told my service manager and was told this is normal.
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Old 08-01-2013, 08:57 PM
  #41  
Mike in CA
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Originally Posted by 10 GT3 View Post
Not likely. Search the GT3 forum for the video of the pre-production car that they were driving it onto a trailer and it kept stalling. I have a feeling it is intentional for clutch longevity.
FWIW, in that vid the driver stalled it once while trying to slowly crawl up a ramp into a narrow enclosed van. Watch from the 1:10 mark:


Last edited by Mike in CA; 08-01-2013 at 09:46 PM.
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Old 08-01-2013, 09:13 PM
  #42  
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Originally Posted by 10 GT3 View Post
Not likely. Search the GT3 forum for the video of the pre-production car that they were driving it onto a trailer and it kept stalling. I have a feeling it is intentional for clutch longevity.
The GT3 PDK is structurally different. Different in the clutches and in the mechanisms. Also, the GT3 has two idle modes, one "free" (no creep) and one with "torque convertor" creep.

I have a 2012 S with sport plus, etc. It has the flat spot, it has throttle tip-in lag and from a standstill it has lurching and lag, but only with a closed throttle and very light throttle movements. If you just "accelerate" as in jumping into a gap in cross traffic, it shows no lag or hesitation. I've had the update and a couple of people drive it, including techs and the service manager, and friends who have other dual clutch cars. They all declare it "smooth, fine, nothing to notice" ... I think there's a level of expectation and I expect better, but people coming out of other dual clutch cars have different expectations or different "but dyno" calibration. I dunno. PDK is a long way from 100% developed, if you ask me. It's awesome on track and wide open in Super Duper Sport Double Plus You Betcha mode, but it's a clumsy oaf if you're in slow-n-go commute traffic or just rolling up to a stop light. I'm "conditioned" to just put it in N whenever it's likely to make a mistake. : ) Speaking of which, I wish Porsche didn't put the "idiot" lights (PRND) on the dash, it's just so crass. By all means, put up a numeral when a gear is selected manually, but otherwise ... seriously?
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Old 08-01-2013, 09:26 PM
  #43  
Mike in CA
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Originally Posted by Carrera GT View Post
The GT3 PDK is structurally different. Different in the clutches and in the mechanisms. Also, the GT3 has two idle modes, one "free" (no creep) and one with "torque convertor" creep.
My understanding is that PDK-S in the GT3 has no "torque converter" creep off idle at all, in any mode.
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Old 08-01-2013, 11:16 PM
  #44  
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Originally Posted by DKC64 View Post
I have a March 2013 C4S and have been annoyed by the hesitation from standstill. Major issue when I'm looking for a small gap in traffic in main road when I'm trying to join from side street - I need to leave a much bigger gap because of this hesitation!

Told my service manager and was told this is normal.
This seems to me to be absolutely unacceptable. Who steps on a gas peddle expecting to go forward and waits for something to happen? On top of it all, this is a sports car that's known for it's immediate response to acceleration. Are they kidding?
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Old 08-02-2013, 09:15 AM
  #45  
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Originally Posted by 911sanantone View Post
I would really appreciate it if 991 PDK owners would reply to this thread and comment on whether or not they have or are experiencing this. This would help folks like me who are still considering which tranny to go with and if this is issue is more pervasive, it may help push Porsche to address in a more timely fashion.
Thanks....
This issue has also been reported by some Panamera owners. So it's not just a 991 issue, but a PDK issue.

I suspect that if you were to take it into the dealer for a fix, the response would be "they all do that".
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