Black Edition

Hi Porsche friends,

In December had my car taken in for the PDK clutch oil service (6 year interval). My car is from 2010.

The service was done at a Porsche centre. After the oil change it was fine, but after 1000 KM the problems began. I don't know if the problem is related to the PDK clutch oli service.

The engine speed is now unsteady under load when accelerating slowly approaching 2000rpm in higher gears. The shifts are a bit rough below 2000RPM. There is an instability when you drive for example 110km/h in 7th Gear (just below 2000RPM). It s clearly visible on the needle and also from the engine noise below 2000RPM. You see some variances of 50RPM. It feels as if the clutch is slipping/adjusting. The car runs fine above 2000rpm in steady state and also when you accelerate much faster (gear shifts above 2000 RPM).

The Porsche Centre replaced the HPFP and calibrated the PDK after my complaints. The problem is still present.

Any thoughts/experience on this would be much appreciated. I saw that a guy in the UK experienced the same problem, but it was not clear how it was solved.

My car: 997C2 from late 2010.

Thanks in advance!

sco77

Read this:

https://rennlist.com/forums/991/1191...0-2400rpm.html

There are several threads with similar descriptions. I don't think anyone has diagnosed the issue yet.

IIRC, there was one guy in another thread with a PDK Cayman that said his car had done that from the get-go.

I got my 2012 997.2 last year and started noticing "surging" after about a month. Took it to the dealer and they said it was "normal" according to Porsche NA. HA! Took it to an indy and their Pcar tech with 40 years of experience said he had never seen that before. All gears other than 7th do not exhibit this behavior. My solution is to drive in "Sport" manual mode most of the time and not go up to 7th. This works until I hit 70+mph on the interstate when the car will shift into 7th. I can tell this because I start noticing surging again. A manual downshift back to 6th and all is smooth again. Other than this "surging" issue, the PDK is pretty darn good.

Black Edition

Thanks for the reply. It provides me with a bit more background. Indeed driving in Sport helps. The problem is in 7th gear. I use Sport ever since I noticed this issue. It looks like that calibration could be a solution. The dealer did that last week. Let's hope that in a few weeks it will be better.

Rorsch

I reckon it might as well be in 5th, 3th and 1th gear while steady cruising in the 1800-2000 rpm range.

I hope another cause can be found in your situation, however it strongly looks like a problem I have encountered. It turned out to be caused by wear on one of the clutches. Replacing the clutch pack solved the issue.

voiceprint1

Rorsch are you saying you had someone work on the PDK, not replace it?

Rorsch

That is correct. Porsche would have just replaced the whole transmission.

I brought the car to a local company specialized in transmission repair. There were a few other Porsches (997 and 991) on the lot waiting to get their pdk issues sorted out.

Black Edition

diagnosed by a well known Porsche PDK specialist in the Netherlands. He said that the clutch was not slipping and for that reason highly unlikely the cause of the problem. He thougt that it could be something with the throttle body or MAF. I had some contact with another Rennlist member. He said that he had replaced the clutch and valvebody, MAF and throttlebody. It did not solve his problem. His problem was solved after removing the carbon build up. Next week I bring the car to a well respected Porsche specialist in the Netherlands. I hope that he can find out what the problem is. It is quite annoying.

ADias

It makes more sense now. It did not seem to be a transmission problem. How many km on that engine?

Black Edition

My car has 97.000km. The PDK specialist told me that slipping of the clutch is not uncommon after 150.000-200.000km

Rorsch

My engine had run a comparable amount of kms as yours when the symptoms occurred. But ofcourse, this doesn't necessarily need to mean something. Let's hope they will be able to find the problem next week, keep us posted!

GTSpure

If I understood you correctly, the idle is unstable?
If this is the phenomenon you describe, I don't think it's related to PDK but throttle and maybe MAF...
A common symptom in 997.2 and in particular in 100k.
By the way, did you also change the gear oil or just the clutch oil? I am curious about the calibration process.

Black Edition

Indeed the idle is unstable, but also around the 1800-2000 rpm especially in 7th gear. You can also notice it in lower gears. Between 1500-200 rpm the shifting is a bit rough. As far as I can see on the invoice the gearoil has been changed. I thought it was the clutchoil. Mistake!. The calibration is new software and I also read that it adjusts the clutch for wear. At the moment I think that my problem has something to do with the throttle, MAF or Carbon build up. I received till now 2 different solutions for this problem (clutch and carbon buildup). According to the PDK specialist it is not the clutch. So I expect something to do with the air intake.

BucketList

Carbon buildup has been known to cause rough idle, so low rpm roughness is not out of the realm of possibility. Also could be the throttle position sensor.

Black Edition

The Porsche specialist did a lot of calibrations. It is better now especially the shifts. Still a bit fluctuating. It is now acceptable. If I want it be resolved he suggested to replace the injectors and remove carbon build up. He thinks that that is the solution. A lot of work because the engine needs to be out. Maybe I will do that in the winter.