Toptier fuel is a good start. DI still has injectors. I am glad that at least one person mentioned that. And, burning fuel will leave deposits on the pistons and combustion chambers. Gotta love those piston carbon deposits, some crud that can break/float away/around, that cause LSPI, PI, or detonation. Won't know if the carbon control prevents the crud that's pushed down and forms in the ring pack area.
These injector/cc/piston pictures are worth looking at, as is reading this article. The product is not available anymore, but IMHO, was no better/worse than any other PEA based fuel system cleaner from any brand:
@stangguy, every time you shut off your engine, the residual vapors cool. This cooling condenses fuel/oil crud which forms, sticks and builds itself up everywhere. Fuel washing, from carbs and PFI engines, clean that hardening condensation buildup from the manifolds/port/valves... downstream of the fuel travel(with quality fuel or when using enough detergents/dispersants/solvents). GDI doesn't have any fuel traveling thru the manifold, thru the intake ports, or past the intake valves.... so there is nothing to 'wash' those areas regularly. The deposits occur when your engine is cooling after running.... condensation/caking/building up. It is not all from the PVC system. As the oil degrades, you'll get more oil vapors. As your engine degrades, you'll get more oil consumption, even more cruddy oil and additive vapors, that condense/coat/buildup over time. The short tripper, pathetic oils/filters, and foolish extended intervals... exasperate the situation. Catch cans are not a solution as PCV is not a primary cause.
I've used IV cleaners, sprays/metered aerated drops/liquid vapors, and they did an excellent job of cleaning the ports/valves. There was no need for pick/scraping or blasting the valves. But, that's a good profit maker for the shop when the clueless schlep shows up with his neglected higher mileage engine. They'll have no choice but to push the "sale". And yes,
@thunderfog, it is definitely excellent PM.
Step one.... don't let the deposits get out of control. Use, and rotate among, all the available valve/intake cleaners, at least yearly or every 10k miles, whichever comes 1st. You should never need to get to the point of scraping or blasting the crud off. I am at double that interval because I am DIY capable and its too easy not to do.
Step two... keep the oil/filter changed often enough. So, all you repeat filter users, 10k mile, or blind OLM extended excessive intervals, are asking for problems. Severe service interval should be considered, quality filters used, along with best oils you can afford.
Step four... control the fuel spray pattern with clean injectors and reduce the carbon buildup. This is easy with TOPTIER fuel and/or by using a bottle of quality PEA/PIB/solvent/ester.... based fuel cleaner added to fuel. Your budget determines interval but try at least 1 bottle every 10k miles. No point in being brand fanboy so rotate among what is available in the stores around you and avoid the cheap stuff.
Step five... short tripping is bad, very bad. Multiple full or partial cool downs, without the ol' EyeTalian tuneups, without good hot highway runs, can increase buildup. You need to get 'er hot enough to burn off everything. The water injection, from a driving in a good thunderstorm, or idling thru the car wash, could also aid the 'cleaning'. Water/meth injection can reduce the buildup but is beyond the budget and skill set of most.
The VVT back washing that a few automakers used was pathetic and a failure. It might've extended the build up time a little. Not impressed!
My 2.4GDI.... oil/filter change severe service 3750 miles(4-6 month OCI) give or take a week of driving. Synthetic and 3.5+ HTHS oils always. Blend or full synthetic oil filter changed at every OCI. Toptier fuel most of the time and grade not too relevant but premium over the summer heatwave. FI cleaner added every 4-6 months. GDI cleaner every 4-6 months(just before OCI). Thumbing nose at the auto manufacturer's conventional 20 grade 7500 mile interval and pathetic OE filter!
My 1.4TGDI... oil/filter changed every 5k miles, about 4-6 months, with fuel cleaner prior week before OCI, and IVD cleaning morning before OCI. Full synthetic oils always, with oversized synth or blended media filter, even though large for engine OE filter is wired back full synthetic which isn't too bad. . Oil grade 20-25% 40 grade synth with remainder 0w20 VW508. Thumbing nose at the 10k interval, overprice dealer filter, and thin oil which seems to be showing consumption issues with many owners.
This isn't a Hyundai thing. This isn't just a GDI thing. This is not a gasoline engine thing. This is not a piston engine only thing. Burning any fuel, vapor condensed deposits, oil consumption, oil/filter quality/interval, carbon buildup, fuel quality, .... affects everything... but at different accumulation rates. GDI moved the crud issue from TDI's and rotaries, and some failed emissions PFI/carb's, to daily higher volume popular products. The methods haven't changed. The reasons have increased drastically.