Carbon Cleaning

[knee_dragger]

Can anyone confirm that engine need to be dropped to perform carbon cleaning on B9 RS5? At 64K and starting to have rough start sometimes when cold or already warmed up. No misfires or codes. Happens on E85 and 93.

TIA

[Dan99]

Can anyone confirm that engine need to be dropped to perform carbon cleaning on B9 RS5? At 64K and starting to have rough start sometimes when cold or already warmed up. No misfires or codes. Happens on E85 and 93.

TIA

Have you done the 60K service, which includes air filter and spark plugs? My B9 RS5 ran better after that service, including the idle.

[knee_dragger]

Have you done the 60K service, which includes air filter and spark plugs? My B9 RS5 ran better after that service, including the idle.

Yes, all service has been completed.


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[wwhan]

Most likely one would need to pull EA839 engine to clean the intake ports mechanically, unlike the EA837.

The newer engines might have less carbon cleaning need, but apparently Audi thinks it is still an issue, if one checks the latest TSB, link below.

I saw this updated TSB for Carbon clean today; Engine does not run smoothly at idling speed - all TFSI engines, 2075530/1 October 8, 2024.

All Audi Vehicles 2005 – 2024

>>>> https://static.nhtsa.gov/odi/tsbs/20...09928-0001.pdf

"Customer states:
• Engine does not run smoothly at idling speed after cold start.

Workshop findings:
• Sporadic misfiring logged in event memory of engine control unit.
• The above complaints occur more frequently on vehicles that are primarily used for short drives.

Technical Background 1
Deposits in inlet ports and inlet valves.

Service
Clean the inlet valves/ ports by walnut blasting.
The cylinder head does not have to be removed. Remove only the intake manifold/ compressor and clean according to the repair instructions.
Granulate blasting unit VAS 294 011
Granulate VAS 294 011/8"

The combustion chambers & injector location are different on the B8 vs B9 V6. See combustion chambers below, older B8 design on top, newer B9 on the bottom. Also valve timing is different.

[wwhan]

It looks like Audi has issues with gasoline additives for carbon cleaning;

TSB Service Info: Use of fuel additives not permitted - EA839 V6 TFSI, 2075515/1 October 8, 2024.

https://static.nhtsa.gov/odi/tsbs/20...09920-0001.pdf

"S4, and SQ5 2018 – 2025
S5, S5 Cabriolet, and S5 Sportback, 2018 - 2024
RS 5 2018 – 2019, 2021 – 2025

Customer states:
Various customer statements can be mentioned, such as:
• Increased oil consumption.
• Engine not running smoothly.
• Engine maintenance requested.

Workshop findings:
Various workshop findings may be confirmed, such as:
• Carbon deposits in combustion chamber or on injector nozzles, visible using a borescope.
• Misfiring.
• No complaint can be determined (“engine maintenance”).

Technical Background 1
Fuel additives can help remove carbon deposits in the combustion chamber, in the area of the piston rings, or in the area of the injection nozzle, for example. However, a negative impact on the engine life cannot be ruled out.

Service
The use of fuel additives in vehicles equipped with the EA839 V6 TFSI engine is not approved and therefore also not permitted."

...................I see another interesting TSB.... it appears to be generic, since discusses the older engines.

MIL on (gasoline quality), DTCs for misfire, air/fuel ratio imbalance, or lean fuel system stored in the ECM P300000
2014753, rev 12, February 6, 2023.

All Audi Vehicles 2000 – 2019

https://static.nhtsa.gov/odi/tsbs/20...31590-0001.pdf

"The use of contaminated gasoline or gasoline with a low content of deposit control additives may result in one or more of the following conditions:
• Excessive accumulation of deposits on intake valves, intake manifold, fuel injectors, and combustion chambers.
• Engine running rough after cold start.
• Excessive engine cranking time.
• Hesitations while driving.
• Rough engine idle.
• Reduced engine performance.
• Poor fuel economy."