2013 carrera 4 PDK with 39 000 km.

At times I do experience some rougher than normal idling or slight vibrations in the range of 1500 - 2500 rpm.

This always happens in comfort mode and never in sport mode. No fault codes or check engine light.

Ran a diagnostic but could not find anything except this which I can not fully interpret. Does these values seem off to anyone?

cyl 6 seem to have higher vibration numbers than the other cylinders and has these high values more often than not. Also the amount of misfires are higher than average.

 

I would put my bet on the CPS. It would effect a bank which you have...however you do have one one the opposite side as well which could be consequential or a coil pack.....they all could be coil packs but that seems unreasonable.

 

I would start by changing the spark plugs and see if that changes anything. While the plugs are out I would also send a camera down into the cylinders to have a look around. Might have some carbon build up.

 

Thank you for your input.
Does this mean that these numbers are outside of what is considered normal for the car?
What is off to you, the roughness values or the misfires?

This happened when I was driving back from a car meet, we had been driving on some country roads mostly between 3500 - 5000 rpm, now I was driving home on the highway ~ 100 - 120 km/h (60-70 mph) in comfort mode. PDK shifts to 7th gear and the engine runs smooth (1500 rpm or so), but it starts twitching every time I pushed the accelerator. So I put it in sports mode and PDK shifts to 6th gear and the engine runs perfectly again. No twitches on acceleration.

Please help me to interpret these numbers:

I have an Engine roughness reference value of 65513 - what does that mean?
At times Cyl 6 has a Engine roughness value of 1024001807....
How many misfires are "normal"?

Thank you in advance!

 

Vario Cam Lift Solenoid

https://rennlist.com/forums/991/1207...wear-item.html

I had the same problem in my 2012.5 C2.
The roughness continued and eventually the car store a code and the yellow fault warning appeared.

Replace both.

search the threads using "vario cam lift solenoid"

 

RNL might have the solution. A Vario Cam Lift Solenoid issue sounds right.

 

I brought the car to Porsche Center where they performed a standard trouble shooting and they couldn't find anything except that there were misfires on cyl 3 & 6. After some discussions, the coils on cyl 3 & 6 were replaced with new coils. Initially there result seemed promising, much smoother idling and more power (probably just a placebo effect) but after driving the car for a few days I can tell that the problem is not yet resolved.

There are still some misfires, but they occur less frequently and the car still occasionally twitches when accelerating on high gears in low rpms in comfort mode.

 

Did they check the Vario Cam Lift Solenoid? Your car is the same ages as mine and I believe that the gaskets in this part wear with age and or use.

The BMW VANOSsystem is similar to the porsche vario cam lift solenoid, it allows variablecamshaft timing of the engine. The intake and / or exhaust camsvary in relation to the crank shaft to optimize engine performance at different engine speeds.

check this out and compare your car's symptoms to a failed Vanos System https://www.autoscopecarcare.com/bmw...lenoid-is-bad/


BMW considers this to be a wear item, checked at 50K and replaced at 70k at a cost of about $2000.


My PCA region did a write up on this part (for 996 engine). https://rtr-pca.org/index.php/the-fr...vario-cam-plus





Seems to me that porsche is trying to lowball maintenance costs by not including this part in ordinary maintenance.

 

Not sure to be honest, I'm going to ask them to check these parts specifically. I'm waiting for a call back from my local Porsche Center.

 

2013 C4S here.

7th gear just sucks...... I get the same stumble and hesitation when you press the accelerator when you are already in 7th gear. The stumble is around the 2500-2800 RPM range.

I started to just flick it manually into 6th if I needed to pass someone so I'd not have to hear or feel the stumble.

In a few weeks I'm going to be doing my 120,000 mile service so I might do coil packs and the VCL's at the same time.

 

Let us know how it goes please.
I hate 7th gear as well and am quite annoyed by how often and early the PDK shifts into 7th gear all the time.

 

Has anyone replaced their CAM position sensor? Any difference in the stubble?

The tech I talk to said there is some talk about replacing this sensor and adding a shim.

Wonder if the sensor was updated throughout the years.

 

Been a while but @991_owner did you manage to resolve, I think I’m suffering from what you’ve described with similar misfire readings if not higher on shorter trips.

Thanks