Dennis R. Cliff

I recently purchased a 2009 Carrera 2 S with 54K miles on the odometer. I noticed that the exhaust tips have carbon deposits that wipe off when rubbed with a finger. In my experience, this much carbon at the exhaust outlet means that the engine is running rich. I would think that the Porsche's engine management would provide a perfect air fuel ratio so now I am wondering if the engine has scored cylinder walls and worn piston skirts that would allow oil into the combustion chambers. I removed the cats and all six exhaust ports had equal carbon deposits about one millimeter thick that was powdery and could be easily scraped off. I have not detected any clicking sounds at idle so far. My question is whether or not carbon deposits as I have described are normal or not. Do I have cause to get the cylinders bore scoped? Many thanks in advance.

vern1

What is your actual oil consumption? People get a huge range of consumption figures

Are both sides the same colour ie seem to have equal amounts of carbon deposits? If the drivers side is darker then that can be a symptom of bore scoring

There are many threads (some would say too many....) on this topic so search for it. Can always get a scope if you just want to do it as its not that expensive

Dennis R. Cliff

Thanks for your response. I don't know how much oil the engine is burning because I have only put about 80 miles on the car. I checked the oil level and there is too much oil in the system according to the computer, warm engine and sitting level. Too much oil in any other car that I have has not been good so I plan to drain some out to get the level correct. Both banks of the engine per exhaust ports have the same velvety deposits of carbon like on the inside of a fireplace. This car just passed DEQ testing but no probe was inserted in the exhaust. They just hooked up to the computer port. I will do research on this forum.

vern1

Over filled is not good so yes drain out enough to get to the top line. Most of these engines burn oil so some amount of soot on the tail pipe is to be expected (or at least wold not be surprising). Its when there is more on one side and by this i mean on the exhaust tips, which could mean trouble.

I am sure you will find more (perhaps much more ) than you want to know on the subject

You will need to monitor actual consumption to get better idea if there may be a problem

Bruce In Philly

2009 C2S 189K miles

Dude, you worry way too much. You will fit in here fine. Drink beer. Relax.

Peace
Bruce in Philly

okbarnett

if you have engine trouble you will get engine warning lights, otherwise it must be running properly. The car will probably use alot of oil

Qwksnke

Based off my 09 C2S, this is perfectly normal and other cars I have owned through the years. I am considering getting black or black chrome tips just since mine have a dull dark stain to them that won't clean up

vern1

Sorry but this is just not true. I had 2 severely scored cylinders and mangled pistons, it burned 1L of oil every 500kms and it NEVER threw a CEL. I am not remotely suggesting that the OP has an issue but problems do not always show themselves with CEL's

Petza914

Vern, this is true for the .1 cars where scoring will happen on Bank 2 of the motor, but because of rhe crossover cat setup shows up on the left tip. If the exhaust is not stock, the side that gets dirtier could change.

The .2 cars don't use a crossover cat setup, which means if the scoring on those also happens on Bank 2, it would show up as a dirtier right tip, or if on Bank 1 as a dirtier left tip.

OP, your probably fine if it's even on both tips and the excessive carbon is probably a result of the oil being overkill and the engine burning it. That's not good for the AOS so get the level corrected. A line below the full indicator is better than a line above it.

vern1

Good clarification, thanks

halsyknox

Isn't the 2009 a direct injection? If so that is the problem. Thats just normal for direct injection cars because the injector doesn't wash over the valve.

Petza914

Actually on the Porsche DFI engines it does, which is why we don't see the same problems that BMW and others do with carbon buildup and valve cleaning intervals.

This graphic is from the Cayenne DFI motor release info but the same one was used in the 997.2 release info.

Bruce In Philly

Its hard to tell if the valves are actually getting washed... the port is between and you can't really tell the locations or what the system timing is. Another way Porsche addresses this is to prevent oil from getting into the induction system altogether... it uses the Air Oil Separator....maybe Porsche figured out a real good one and our problems are just delayed. It does seem Porsche did something right here.

Peace
Bruce in Philly

Petza914

Washing the intake valve is the only thing that explains to me why guys North of 100k miles on their 997.2s (like you and Wayne), and 957 and later Cayenne owners aren't seeing a carbon buildup issue on these DFI engines at higher mileage.

I don't know about the 997 Turbo but on the Cayenne DFI Turbo for emissions reasons, they actually run the crankcase vent that contains oil vapor back to the driver's side intake. And although it too has an AOS, some of the vapor condenses in the intercooler and some passes through for a reburn, but even with that oil going back through the combustion chamber on that side, carbon buildup and coming of the valves is still not a major issue, so I think the fuel has to be washing the intake valves.

Wayne Smith

There have been naysayers regarding the 9A1 motor and whether the intake valves get washed or not. The lack of a problem is anecdotal evidence that the Porsche engineers did a good (or even great) job, one way or the other. I believe Porsche had (and has) their DFI act together.

On the other hand, the exhaust valves don't get washed. To the OP ... change the oil to get a reference point (unless, or even if, you have full maintenance history ... you may want to do all the services). Clean your tail pipes. Then get out and drive. After enough miles check the oil, check the tailpipes, and be cautious to avoid Forum Flu (the emotional fear that the sky is falling on your ride).

Welcome, you've got a great car, congratulations, enjoy.