Why does engines get build up on the valves? What causes it? Something with the Di but why
Cheap oils + fuel + moisture evaporating and condensing on the intake side because of crankcase ventilation.
Port injection can wash down everything downstream from the injector. DI doesn't. [/quot
Right. Fuel washes over intake valves in port injected engines but not in DI ones, so the oil vapors coming throught the PCV system can accumulate and harden on the valves. Some DI engines seem worse than others in this respect. So far, it looks like the normally aspirated Focus is one of the "good" ones, but it doesn't hurt to be cautious.