flightmedic

Eddie so was it carbon buildup or more injector issues?

Eddie13h

when it had 15000 km, it was injectors issue, now at 56000, it is carbon build up issues. also flightmatic, did you find the fuel injector cleaner help your carbon build up issue. also can you tell me the cost at dealer. thanks.

flightmedic

Dealership didn't say anything about carbon buildup but at 54000 kms looks like the injectors went again. They replaced all 6 for the second time. The service advisor at Royal Oak now says this is a known issue for Audi and they are hoping for a more permanent fix. It's the Old Audi/VW coil issue all over again.

JohnEnglish

The carbon build up is due to the direct injection system. With "regular" injectors, the fuel in injected upstream of the valve and is therefore able to "wash" the valves of any unburnt residue. In a direct injection system the fuel is injected directly into the cylinder so the valves do not get "washed".

Lexus has solved this problem by adding a second set of injectors upstream of the intake valves that'll allow them to be "washed" with fuel. It also has the added benefit of increasing efficiency at low RPM as traditional fuel injection is more efficient at lower RPMS and DI more efficient at higher RPMs.

Ford has solved the issue by adding additional filters to the PVC line to make sure that any unburnt hydrocarbon solids are filtered out before going back into the intake.

Eddie13h

So John, is there anything I can do either to delay the carbon build up or even to eliminate the build up? ie. would fuel cleaner or fuel injector cleaner help at all.

JohnEnglish

No becuase the issue is not with the fuel but rather the buildup of deposits from the combustion cycle. Some people have found that adding an oil catch can has reduced the amount of carbon build up as it's trapping oil and other unburnt particles before they can re-enter the intake via the PCV system.

Eddie13h

Thanks John for your valuable comment.

hojimoe

drive it like you stole it from time to time!


I was sure my car had carbon problems (3.2L) but I had no symptoms, but got the car scoped last month, and it was spotless

I use ultra 94 from petro, or shell v-power exclusively - never esso - I had a bmw stall over and over again after getting esso premium a few years ago, and never went back

Eddie13h

Thanks. I guess that was my problem - not driving it hard enough. I always tried to keep it under 3000 RPM.
I did exclusively use Shall V-power though.

Ridgeback

I'm using Petro Canada Ultra 94, so far no issues after one year. Also no excessive oil consumption with mostly Hwy driving. My Audi is the 2 liter ,2011 and used mainly for Hwy trips or pleasure driving.