VAG TFSI engines – Cleaning carbon residues on intake valves

The problem

In Direct injection engines the intake valves are not cleaned by fuel injection, contrary to indirect injection and carburated engines.
Because fuel is injected directly in the combustion chamber, all combustion and oil residues on the intake valves stay on the
valve stem and start layering up.
Within 20.000 to 30.000km the intake valves start changing shape because of the residues on them, reducing the engine’s
performance and increasing fuel consumption.

However, the intake valves can be cleaned without removing the cylinder cover and disassemble it.
The results are very impressive.

Within a few hours the valves are cleaned and the engine’s proper operation is restored.