Carbon buildup on intake valves
#1
Carbon buildup on intake valves
I own a 2008 A6 with the 3.2L FSI engine. After 15K miles, the intake valves had to be cleaned to remove excessive carbon buildup on the valves stems which was causing rough idle, increased gas consumption, hesitations under acceleration and finally a check engine.
I always used premium gas and I find it unusual to have the intake valves cleaned so soon for carbon buildup. I never had that problem with my previous cars and I normally put over 150K miles on them.
It seems to be a known problem with the FSI engines. These engines get the gas injected directly in the cylinder and since the gas does not flow through the intake valves their is nothing in the intake manifold to clean the residues left from the contaminated fumes coming through the PCV and ERG systems.
Audi started to use this technology in 2005 with the 3.2L engine and therafter on the 2.0L, 3.0L and 4.2L engines. Has anyone experienced a similar problem with a FSI engine?
I always used premium gas and I find it unusual to have the intake valves cleaned so soon for carbon buildup. I never had that problem with my previous cars and I normally put over 150K miles on them.
It seems to be a known problem with the FSI engines. These engines get the gas injected directly in the cylinder and since the gas does not flow through the intake valves their is nothing in the intake manifold to clean the residues left from the contaminated fumes coming through the PCV and ERG systems.
Audi started to use this technology in 2005 with the 3.2L engine and therafter on the 2.0L, 3.0L and 4.2L engines. Has anyone experienced a similar problem with a FSI engine?
Last edited by golfaddict; 10-15-2009 at 09:58 PM.
#4
Re: Carbon buildup on intake valves
Thanks for the feedback. However, when I reported this problem to Audi Canada they made no recommandation to prevent it to occur again other than suggesting that intake valves cleaning should be a routine maintenance item on these engines. If it is so, why it is not specified in the car maintenance manual?
Cleaning valves is a temporary solution but a permanent solution is required to ensure the long term efficiency and reliability that the FSI engines are supposed to have.
To me, it appears like a serious design fault and I am curious to see how other manufacturers will resolve this issue with their direct gas injection engines. It seems Porsche, Mazda have experienced similar problems lately. Time will tell...
Other than that, this Audi is a great car. I will let you know if this problem recurs next year.
Cleaning valves is a temporary solution but a permanent solution is required to ensure the long term efficiency and reliability that the FSI engines are supposed to have.
To me, it appears like a serious design fault and I am curious to see how other manufacturers will resolve this issue with their direct gas injection engines. It seems Porsche, Mazda have experienced similar problems lately. Time will tell...
Other than that, this Audi is a great car. I will let you know if this problem recurs next year.
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