Originally Posted by FormerE30Owner
Better question - How does one prevent the carbon buildup on direct injection systems? I know that with port injection, using Techron and Lucas in the fuel (top tier fuel), prevents the buildup. I have never had to have my valves cleaned on any of my 8 BMW's over 45 yrs and 1 500, 000 kms using those products.
These products won't work with direct injection however, since the intake valves never see the Techron or equivalent liquid.
Salut, Bob P.
Keep on top of PCV system, or install a catch can system and walnut shell blasting every 45k miles are about the only realistic options.