As an Audi RS4 owner I've become well versed in the world of direct-injection carbon buildup issues on intake valves/runners/flaps on pretty much every DI motor (Porsche Cayenne, Chevy's 2.0L, anything under the VW umbrella... even Toyota had to rethink their direct injection engine due to bad carbon bulidup[they were the first to include both port injection and direction injection in order to keep it clean and smooth out cold startups]). Getting side tracked now...

brianja explains well, good thread to catch you up. Likely there will be the same band as we had on the RS4 forums of people saying "My car hasn't gone down on power" since the buildup is ultra gradual over thousands of miles and slowly robs you of power until you get a CEL.

The face-lift of the 997.2 drew my interest but then I learned it was direct-injection :/ Furthermore, I see photos of 997.2's with lower miles with the same baked on, hard as a rock, carbon on the intake valves as everyone else.

2010 911 w/ ~24k



You can see the lighter gray area is the hardened carbon. The more slimey/wet looking stuff on the intake walls and top of valve stems is the future cake.

Much like this RS4 with better lighting(Carbon cleaning was good for 40 @wheel HP on this one).



Anyways... I just wanted to define the subject before getting to the goal of the thread.

Cleaning the valves is the fastest way for you to gain HP that you don't even realize is lost. So, multiple questions are floating in my mind for those of you who are addressing the issue:

Who here is cleaning it themselves? (I've done one, ugh)

Who's taking it in for cleaning? What are you paying?

How is the dealership treating the issue? Denying it? Boroscoping the intake to see the buildup then cleaning?

I know for a while Audi was saying there was no issue, then they started giving people a fluid to add to the gas tank(even though the fuel doesn't even touch the intake runners on a DI engine, awesome), finally they started popping the engine and cleaning it out. Recently, Audi has started sending out letters stating they are extending warranties on certain DI-engined cars for free carbon cleaning(RS4 didn't make the cut, grrr)

A friend went through the exact same ordeal on his BMW 335 and Porsche Cayenne a year or two ago. (He got rid of both after that)

I'm curious how Porsche is approaching this now.

 

Sorry, off topic but I love the Avatar. I used to have an 01 RC51 - loved that bike!

Anyway, I have heard nothing on this forum related to Porsche dealing with it, and while I am no expert on the subject, I would say that means that they are doing nothing about carbon build up and we are on our own. How effective is seafoam in dealing with this - I know that the can is meant to be unloaded directly into the injection system-never used it though.

 

Let's see, it took them how long to act on the IMS issue?

 

I rarely see this brought up on 997 forums. Most 997.2 owners believe the DFI engine is bullet proof. Could it be that owners are blissfully unaware of any potential carbon build up issue? Or simply don't feel the problem exists on the 997.2 engines?

 

I think both those questions are the same

Obviously it's a problem. I know for a few years it was head-in-sand over in the RS4/R8 world about the issue existing. Everyone said they still had the same amount of power(because it's so gradual you don't feel it declining over months/years).

Surprise surprise, you get it cleaned and it feels like you put a supercharger on it(as stated in the link I put in the OP). My RS4 gained 42HP at the wheels with a before/after dyno(same dyno/temps/humidity/etc). It was incredible feeling. It's been 11k since being cleaned and has lost it's top end pull that otherwise rips you back in the seat.

Anyways... I was hoping some people had some experience on cleaning it out here? I asked the local Porsche dealership and they said they've only been cleaning carbon chunks out of Cayenne's :/

 

Previous posts on this have been pretty much met with denial. Be interesting to see how this plays itself out. Good heads up for the gen2 crowd.

 

I have seen this same trend on Bimmerfest forums for BMWs. When the 535 with twin turbos and DFI arrived everyone thought it was great but then the fuel pump failures, injector failures. All were in denial about the carbon buildup with a " it only happens with Audis and VWs" mentality. Today, it is a standard $400 -$500 procedure to clean carbon out of BMWs with DFI. That is now "the big tuneup."

 

I have VW Tiguan as DD, CEL was on and notice there is significant amount of power loss at the wheels, took it in the dealer and they told me my DFI has carbon buildup and need to clean it with solvent and high pressure induction, my car is still under warranty but they deny the claim saying it part of the regular maintenance. The cost for induction cleaning is $605 and manually take it apart and clean is $900 but to replace the Fuel Injectors would cost me $1600. He also saying when the injectors failed, it is NOT cover in their warranty. That really **** me off bc I follow all their schedule maintenance and use ONLY recommended gasoline. I am not sure Porsche have the same warranty coverage as VW, but they are under the same umbrella with VW and of course the price to clean or fix a P-ride is probably more than VW

 

Assuming this carbon build up is inherent to any DFI engine, one would assume the same issue applies to the 991. My trusty old 997.1 has been very good to me, I may just keep her even longer now...

 

Suddenly, I'm sooooo glad I've got a 997.1.

 

I haven't heard of any reports of this on the 997.2

If there was a problem, I would have expected it to rear its head here on the forums, but this is the first picture I've seen.

 

I don't think fuel injectors are the issue NOW due to the 997.2 relatively new, but carbon buildup WILL be an issue eventually, given that ALL 911 SHOULD BE using PREMIUM GASOLINE hence the buildup is a slow process. But I THINK it will be an issue soon for the early 997.2

 

sub'd

 

Several message boards and other "how-to" sites I scanned through mentioned having good results with using BG 44K, a fuel additive that is supposedly made to remove carbon from the valves, pistons, fuel injectors, etc. Even a fellow Porsche owner posted and said it was recommended by his dealer. He used two cans and felt a noticeable improvement in engine performance. He now uses a can just before getting the oil changed and says the results have been positive.

 

Well it may be your last car then untill all electric since almost all new gasoline cars currently being built are DfI. I can't believe that every manufacture on the planet hasn't addressed this issue. I had an Audi dealer tell me that this is not an issue in their new cars, of course he is a car salesman