When I was doing my intake manifold cleaning, I was shell-shocked by how much oil and [censored] was in the intake tracts. I'm hoping this can help future DI engine owners understand what they are facing.
I was also super-happy that my intake valves were ok because thankfully Honda back then wasn't stupid and hadn't fallen for the false promises and company greed that comes from using a single set of Direct Injectors.
FYI, if you own a Toyota with D4-S or are a lucky owner of an Audi with the 2.0T in Eastern Europe - you guys all have a set of port injectors in order to meet and beat the emissions regulations that don't allow the type of particulate emissions that DI is responsible for. Smart choice!Pics --
The seal that faces the top of the intake manifold
Intake Manifold cover. The dark crusty stuff is the soot marking the EGR system.
Intake Manifold plenum center part. By design it catches the majority of the oil coming in from PCV system. This is 202.5k mi. of collection. It took 4 hours with Throttle body cleaner and a toothbrush to take the heat-caked oil off.
The following are each of the 6 cylinder intake ports on the engine. Just think what my intake valves would look like if the injector wasn't there to keep them clean. Based on this, I can say there's absolutely no way in [censored] a DI engine can survive for long without a 100.00% removal of all contaminants from intake air (FYI, this is impossible as of right now in production cars. An OCC is a must-have
if you plan on buying a DI car.)