I have this habit of using a bottle of the Techcron fuel injector cleaner for every few tanks of fill up. However, it just occurred to me that the Porsche engines are now all DFI, does it make a difference? Can I even (or need to) use the fuel injector cleaners?

Thanks.

 

I think the older cars benefit from Techron. I use it in my old Benz, but that's a 24 year old FI system. It probably won't hurt the newer cars, but with direct injection, the benefits might be debatable. The mechanic that works on the Benz (also Porsche master certified) tells me not to use more than 2 - 3 bottles of Techron per oil change.

Experts please weigh in!!

 

The big issue with DFI engines is with carbon buildup in the intake area. With these designs, Techron will not help that condition.

 

How can I tell if I have carbon buildup? Does the dealer regularly clean it out as part of the maintenance?

 

If there is a severe buildup of carbon in the intake area, one would notice a gradual decline in performance. The dealers do not check for this. It would be too expensive to do this on a routine basis. From what I have read, if it is does become a problem, it is more likely to show up after 30,000 miles or 60,000 miles. At that point, it would involve removing the intake manifolds and cleaning the intake ports and valves. At worst, a valve job. ( expensive and very expensive, respectively). I must add that I am not sure how often and how soon this happens for the majority of DFI engines. There have been some nasty looking pictures on the net of some Audi engines with heavy carbon buildup. I have a BMW 535 with DFI and almost 60,000 miles. The car is running OK. The problems I have had so far are related to the pump and fuel injectors. Actually VW/Audi has the most experience with DFI engines. They have been using DFI for years and in a large number of cars.

Some things to think about....

Also, does the carbon build up and level off after a certain amount builds up? In the end how bad does the engine performance eventually get?

All Diesel engines are DFI. Is there a problem with them? I did have a 1978 VW Rabbit with a Diesel engine. I had it for 5 years and 70,000 miles. It ran flawlessly until the day I sold it. Are the modern Diesels more likely to have problems?

 

I have heard and read several sources that said if you use Premium fuel (and tier 1 fuel) there is really no need for Techron or other cleaners. Premium fuel includes sufficient solvents to keep the fuel system and injectors clean. I have used Techron on carburetor engines, but never on F/I engines. I have no experience or knowledge on DI engines, though.

 

I agree that the level of detergents used in premium fuels can keep the fuel injectors clean without additional additives. For port injected engines, they can keep the intake area and intake valves clean as well. These fuels cannot, however, help direct injected engines keep their intake area / intake valves clean.

 

I use to own an Audi RS4 and that is direct injection.

The only solution found to the coke problem was ..

http://www.wynns.net/product_files/d...l)%2023079.pdf

If you look here this provides some more details ...

http://www.mrctuning.com/index.php?o...d=41&Itemid=18

DON'T be put off of DFI it has good benefits

 

Please post examples of DFI intake gunk in the 9A1 engine if you know of any. There are plenty of 50k mile engines out there.

Should there be some deposits (which BTW are soft) have you heard of Top Engine Cleaner?

 

This is a pic of a DFI Cayenne engine originally posted on RennTech. I have seen similar pics of Audi DFI engines. Not sure if the boxer style engine will have any impact, positive or negative, on this issue.

 

Yes, that is a pic of Cayenne engine and I first posted it here when the question arose at the time the 9A1 DFI engine was released... The conclusion then was that the boxer DFI design was different and that should not be an issue. So far I heard no reports, and there are several 50k+ mile cars out there.

Those raising the 9A1 fear spectrum please address the following:

1 - How many 9A1 DFI engines have you seen with that problem?

2 - Please post a 9A1 DFI engine intake tract gunk photo

If no answers to those questions... I suggest stopping baseless speculation.

To those who worry... learn about Top Engine Cleaner service...

 

I do not have any such pictures but I would be very surprised if there were no carbon buildups with boxer engines. Remember, relatively speaking, there are very few Porsches out there with DFI. Why would you think a 9A1 engine would be any different than other DFI engines in this respect?

Again, the carbon build up may not always result in a problem for some cars.

 

Your experience is not unusual. DFI is only new to internet mavens. We've had DFI in aircraft engines since around WWII. Maybe a little before.

As several people have said, I'll worry about it when I have a symptom to worry about. Not to be a spoil sport, but has anyone else noticed how the predicted mileage of occurrence keeps moving outward with the length of time the 997.2 engines have been on the street? At first, when they were brand new, and we happy owners all were saying how great the new engine performed, it was "wait until you reach 10k miles and your engine is coughing and choking." Then it was "wait until twenty thousand!" which I passed last year some time. Now it's "between thirty and sixty thousand."

I expect the apocalypse prediction to reach "100k to 150k" about the time the preeminent doomsayers notice that prices on used dot twos have reached the range they can afford. The DFI engine will look a lot better to them. That was pretty much the pattern with forecasts of disaster from using water cooling.

Gary, not holding my breath

 

Because the geometry is different in a boxer engine. The injector may actually spray the back of the intake valve.

 

The carbon buildup issue is going to be a big issue that we're going to be hearing more and more about as more of these cars get to and past the 60,000 mile mark. It's long been a known issue among Cayenne owners, who tend to drive their vehicles more miles than Carrera owners, thus there are more Cayenne's in excess of 60k miles.

I personally know of a DFI Cayenne that spent over 120 days in the shop, at a Porsche dealership, while they tried to figure out a way to correct the issue. They tried everything, but still got carbon buildup, cat warnings, etc. They got PCNA involved, who got engineers in Germany involved, and still no fix. Finally, it took an old-school air-cooled expert to adjust the timing and no more issues...so far. We'll see.

However, I believe in Porsche, so I'm confident they'll ultimately sort this out if it does in fact become an albatross.
CATTMAN