Bruce In Philly

2009 C2 S Dec/2008 Build

Well solved is a bit strong but the issue is very much improved along with other interesting changes.

Solution: Re-flash the ECU with Porsche's more modern programming. Perform the "long version".

Problem: I get an odd thump or hesitation under mild load around 2700 RPM. It can happen at lower or higher RPMs depending on load, pedal position etc. It is more pronounced when engine is still cold. It happens in all gears. Does not appear to happen under hard acceleration. No CEL and the Porsche computer recorded no faults.

Suspect: Variocam Plus transition from low to high lift.

Advice from the 'net: Folks who have this symptom have posted that their dealers say it is normal with some cars having it and others not. Some suggested it is a "lazy" solenoid/actuator. My dealer never heard of the issue.. I was the only complainer.

Ford Engineer's Advice: Reflash the ECU. I took my friend who is a 30 year Ford engineer and now in the corporate services side for a ride. He immediately said it was most likely a software issue and have Porsche re-flash the ECU. He said the industry classifies this type of issue as "driveability". This is code for "nothing is wrong but we are going to fix it anyway". He noted Ford, and all car companies, are constantly tweaking the ECU programs/ignition/shifting maps etc. for improved drivability. Think Windows updates. The company may not issue a TSB unless it is a common complaint. If the TSB tells the dealer to reflash the ECU, the customer gets a summation of many many tweaks.

Cost for Flash Update: Zero, the dealer did this for free. While I didn't ask why but did thank them, my Ford friend noted the ECU is considered part of the emission control system and is subject to the fed mandated 5 year warranty, therefore my 2009 is still under that umbrella. I know the guys at my dealer well (scary eh?) and they doubted this flash would fix the issue but did it anyway (I did reproduce it for a tech... he didn't know what it was but thought it was the Variocam Plus transition). The tech said there are two types of re-flash: a short one and a long one. I asked him what the difference was and he said he wasn't sure but he did the long one on my car.

Impact of the Re Flash on thump: In short, it definitely changed the engine behaviour and the transition is now better masked. It is still there and when cold, is more pronounced. I get this as the software can not change the mechanism, but it can change when things occur, retard timing... etc. Before, I would press the gas, the revs would start to climb and if I was in the mid 2000s, I would then get a thump. Now, it appears the transition occurs as I press the gas so it is hidden and less noticeable. Overall I am happy with this... but I am more impressed with... read the next...

Unanticipated Changes: Wow. This surprised me. The darn thing is just smoother. The idle is way smoother. I was not unhappy with it, but it is very different and better. Before the car would shake a bit and wag its butt as I sat in my garage. Now? Smooth as silk. The engine also appears to be more responsive.... such as when I blip the throttle when I downshift. It appears to jump and respond quicker. And here is an odd one.... I think... I think.. I am getting better gas mileage. Before, computer read my average mileage was 18.9. Now after resetting the computer immediately when I picked up the car, after about 5 tank fulls, a variety of highway, dopey city start stop, etc. etc. is says 20.9/21. Will this hold as I drive more? I dunno. Ok, now for the big HP question: no I don't think so. Other minor improvements/changes... when I shut down the car, the engine would jump/jolt a bit. Now it just stops. Look, these things are pretty minor, so it is not like the car was a mess before but there are definitely differences and I like them.

Should you do this?: My car is an early build, Dec/2008 with the new DFI engine, so it stands to reason that earlier cars do not carry the improvements of later cars. My Ford friend noted that cars with a new component, like say PDK, will have more tweaks when new. All I can suggest is that if you have a 2009 and have the thump, get it. It won't make it go away but it will make it less annoying and you get other smooooth improvements.

I hope folks with my issue finds this information useful and I apologize to the dealers who may now have to deal with us neurotic owners.

PS: If you think about it, why should our car's software be any more stable than Windows or Android? Just look at the crazy stuff in the Durametric software that we can control.

Peace
Bruce in Philly

Jaws1

Great info. Mine's an 11/08 build and when the car is cold, it exhibits the same trait. Did you have to demonstrate the hesitation in order for them to perform the re-flash?

Bruce In Philly

I did take the tech for drive and reproduced it. Unfortunately, the roads didn't allow for the more dramatic thumps, but he did experience it. Was this required for the re-flash? I don't think so as we discussed the re-flash before the drive.

I will make some suppositions here.... If you have a good relationship with them, they will do it. If you have a dealer who heard of this issue before so they don't think you are just another annoying neurotic customer, they will do it. If all else fails, admit that your are a psychotic neurotic and just offer to pay for it; why wouldn't they then do it? I think it took about 1 hour to perform and I waited for the car. So maybe the cost is one hour of labor?

Post your experience and opinions please.

Peace
Bruce in Philly (yes, a neurotic mess)

JustinCase

^^^^^ . . . or hit them up to do it after taking your car in for other service.

DGrayling

Thanks for the write up Bruce. I will have to look into this for my 2009C2S.

Rich

MMK110464

Anybody else got same results as Bruce?

wheeler

Also an early 09. I've noticed it when the car is COLD and probably around that same RPM (I'll take notice now). I don't think I notice it much if at all one I'm up to temp. The times I really notice it is when I really short shift it, like when it's just dead cold and I'm pulling away, I would guess I'm shifting almost exactly around that range from 1st to 2nd and it will thump/stumble in an odd fashion.

I have ZERO relationship with the dealer as of yet. I do have CPO for another 18 months and need to take it in for the creaking/squeaking spoiler actuator. So I'll give it a shot!

Misdirection

So this is maybe irrelevant to folks that don't ever take it to a track, but after the re-flash, can you still left-foot brake? I always hear that my car shouldn't allow it, but it does currently.

Edit: to clarify, I mean does it let you overlap brake/throttle without cutting engine power?

Jaws1

I took mine in and the dealer checked the ECU version, and it's was up to date. They performed a "throttle adaptation" (?) procedure and there seems to have been an improvment, or it was the classic placebo effect.

chago996

I haven't seen the 991 folks complain about this issue. It has a newer version of the 9a1 engine and I wonder if this rpm thump still exists in this newer engine, did they fix it, how.

MMK110464

Hi Chago:

Funny that you post this comment. Here is a thread in which 991 owners complaint about this exact issue...and you are one of the posters in the thread

slight hesitation on accel at 3k rpm (991 base, MT)

I also read a similar thread on the other forum

chago996

52 and I can't remember yesterday, let alone a year ago!! smiley face, smiley face and I can't remember where that smiley button is, damm

dasdman

So glad I stumbled across this topic. Mine was built 02/09 and I am noticing this same behavior. I too have yet to build any kind of relationship with the local dealer, but will have to do so. My car is CPO'd until 06/15 so I would hope that a firmware update should be a no charge service.

Mine also stumbles when coming off of high idle at a cold start. Stumbles may be the wrong word, fluctuate up and down about 250 RPMs for about 20 seconds before it drops down and stabilizes.

Excited in hopes that there may be some improvements for cold driving.

wheeler

I'll be taking mine in for the squeaking spoiler. I'm going to tell them about it and see what I can get done. It's nothing super critical, but I did take more notice on some recent drives and it's right there in short shift land around 2700-3000 rpm, even when the car is warm it will do it. Mine does idle a little rough as well, but it may be just how the car is in general. My comments again are exaggerating a very minor, non-perfection issue. The car runs great and hauls *****!

wheeler

Thought I would update here as well...I took mine in for the spoiler motor replacement, which they did.

They of course could not reproduce the issue of the hesitation or bump around 2700 rpm...it does it but they aren't driving it every day either I suppose. The tech mentioned he felt it took a few more cranks to start than normal, said it could be the high pressure fuel pump, but since there was not code thrown, they could not warranty it yet. It did have the HPFP replaced in 2011 under recall. I asked the SA about an ECU update, he said nothing, knew nothing, deer in headlights. This was my first trip in to Aristocrat, so I'll get a different service adviser next time and try again. You would think if there WAS an ecu update available it would be standard procedure to flash and keep it updated?? Apparently not. I really wish we had another dealer here in KC.