BogdanR

Hello all.
I've been dealing with a headscratcher for some time now. It all started Feb 2016 when I took my 2011 Cayenne S in for the 90k service. Immediately after that I've started getting the "Reduced Engine Power" flashing a couple of times on the dashboard, only when starting off with the engine cold. The message flashes a few times within the first 2-3 km of driving and once the engine heats up it's not doing it anymore. There's no physical symptom in the driveability of the car, no hesitation I can feel. (I'll attach a small video of it at the end). The car was still under CPO and the Porsche dealer spent almost 6 months trying to troubleshoot the issue. They drove the car with the laptop attached and determined it was a knock sensor issue, they've seeing in on # 2 and 3 cylinder. Things they tried were knock sensor replacement, reprogramming the DME, replacing the DME... with no recourse. Finally they flush the oil and refilled it fresh. The problem went away. I cannot find any mechanical possible explanation as to why this was happening and why this fixed the issue. 10k km went by without any incident whatsoever. Having an oil change last week brought the problem back, only now switching from Liqui Molly back to Castrol did not fix it anymore. I'm really scratching my head here...

Here's a link to the message: https://drive.google.com/open?id=0B5...EQxMGdTQVZ5Szg

Anyone here ever experienced anything like this?

Please help!

CarGuyNVA

Hi there. I'm not sure I have much to add to this, but I hope these are not symptoms of the cylinder scoring issue we hear about in the V8 S models from time to time. Hopefully it's something much less severe.

I'm kind of surprised the dealer was not able to identify the source and correct it after all that time. Is your vehicle still under CPO or has that expired?

BogdanR

The car is fresh out of CPO and oddly no one came to me to offer an extension...

BogdanR

I will have a boroscope done next week, Will report back

Andy E.

Bogdan,

1) Where did you get the oil change done prior to the dealer oil change 10K ago?
2) Who recently changed your oil? What grade/viscosity oil did you use on both Liqui-Moly and Castrol?
3) What were the outdoor ambient temperatures like when you experienced the "REP" messages (Besides the 15.5°C temperature when you posted the video)?

J'sWorld

Have them check the transmission temp sensor when it's cold and and hot.

TomF

I sure hope it turns out to be something simple although it could be the symptoms of a larger issue, like cylinder scoring. Fuel could also be an issue. I dumped a can of injector cleaner a couple of years ago into my fuel and 200 miles later, in the middle of nowhere, the CTT went into limp mode. I suspect the ECU detected misfires like it was receiving bad gas and tried to protect itself. A fresh tank of fuel and all was good, but not until after I went though all the other more serious scenarios.

You could also swap coils from cylinder to cylinder to see if that helps. I am always amazed at how poorly coilpacks do over time. 30k miles is the longest interval that I would go anymore, especially on a CTT. They eat coilpacks and plugs for lunch.

Best of luck!

Cheers,
TomF

BogdanR

See below Andy.
All oil changes were done either at the dealer or at very respected independent, all done at around 10k km.
All oil was 5W40
The temperature was irrelevant. It started in February when we had anywhere from 0C to -25C and it was still going on thru dealer's troubleshooting at the end of June at +20C to +30C.

BogdanR

I lost my 997 to cylinder scoring, one year out of CPO. It still pains me. I see no oily exhaust though and there's no ticking and no other symptoms apart from the message. the dealership changed two coils already, one around 79k and the other 7k later. The symptoms were apparent though. A flurry of messages and a rough running engine. It amazes me how the Germans can't seem to be able to design a reliable coil.

deilenberger

5W40 is WAY too high a viscosity for -25C...

There is a mistaken school of thought that thicker MUST be better. It isn't. Blackstone's head guy had an interesting blog article on this. He's all in favor of thinner oils as long as they have an adequate "hot" (2nd) oil number. Getting lubricant to the sliding surfaces fast is done much better by a thinner oil.. and his access to literally thousands of oil tests counts for something in my mind. He's also not the only one to make this argument.

BogdanR

I agree 100% I will probably insist on switching on 0W40 most likely Mobil One even though some people call it liquid death. My old Acura run on it without one single issue for 280k.

BogdanR

Back with the results from the boroscope. Nothing to worry really, normal wear except on #2 and #3 where is a little more but also not out of the ordinary...

TomF

That's really great news!

FWIW, at the early stages of scoring, it starts below the rings and cannot be seen from above and needs to be scoped from below. At the later stages, codes are thrown and scoring can be seen with a borescope from above.

With codes being thrown, but no scoring above, it appears that you are out of the woods on the scoring issue.

Keep us posted as to your findings.

Cheers,
TomF

Max432

I had similar issue with the reduced engine power warning on my 2014 Cayenne S. Driveability was fine and light would generally go away if the engine was at operating temp. Dealer installed a new hi pressure fuel pump under CPO and I've had no problems since. At the time it happened I googled the issue and it appeared to be a common fix to the problem.

TomF

The PO of my car apparently had the same problems with my 2009 Turbo S. Check out the notes on the invoice.

Cheers,
TomF