direct injection carbon build-up

[Jeff_DML]

ford claims not a issue for them

Don't fret about deposits on the back of the intake valves that have plagued some other manufacturers' direct-injected gasoline engines, said Stephen Russ, the Duratec GDI's technical leader for combustion.

Although he called intake-valve deposits "a fact of life" for GDI engines because they lack the raw gasoline sucked in over the intake valves of a conventional port-injected engine to "wash" the valves, Ford's figured out the proper injection-timing calibration to help eliminate the problem.

But he also said the technology of injection components — particularly the high-pressure solenoid injectors — has quickly matured, meaning excess valve deposits should be a thing of the past.

http://www.insideline.com/ford/focus...e-at-ford.html