Vegas RDX

I find most car makers are choosing this form of fuel delivery system. Well, their engine builders really. After investigating this form of fuel delivery system a large many of critics are saying the back of the "delivery" valve has no way of cleaning itself. I find this is a conflict in reasoning because what is cleaning the back side of the exhaust value? Heat? So my question is, Would a modern day car manufacture flood the car market with destructive engines in high priced autos and cause an snow ball effect that could reach into many years of efforts to make a reputation. I know there is some cars the auto makers would rather like to forget. But with the advance of research via the internet news travels fast fact or fiction. I'm sure , I hope, these engines were tested in extreem conditions so this propaganda carings no wieght and this issue of negativity regarding direct injection is just speclative and the longevity of these engines will show they were built with knowledge of possiable problems and the manufacture has concidered these and show it will be a bench mark engine for now and the future.

justnspace

iTrader: (1)

Early DI systems sucked, think way back in 2006 when Mazda did it. General maintenance included walnut blasting the intake manifold.
Honda introduced DI way late in the game to perfect the technology

losiglow

iTrader: (1)

I've asked several folks about the DI in the V6's and so far it seems it hasn't been a problem. However, oil consumption - specifically blow-by, is going to be a primary factor in how much oil returns back to the intake and gets deposited on the intake valves. And from what I understand, some of the Turbo-4's Honda is putting out tend to have some blow by. Well, turbo's in general often have more blow by than NA.

Either way, once I get a car with DI, which is pretty much inevitable, I'm going to be using that CRC GDI Intake Valve cleaner routinely to prevent buildup. That, and get a good quality oil catch can.

AZ4035

I installed my catch can close to 800 miles ago. After checking it a few days ago it indeed has collected a small amount maybe 1/16th of an inch of dark oil. I would definitely still install an OCC if you plan on keeping the car. My car was sent to the dealership for service with the can installed and it no one said anything about it being in there as well

PAPI007

IMHO, Toyota perfected this issue with the D4S engine, which combine both direct and port fuel injection. These engines are bullet proof.

RDX-Rick

Thanks for the update, and I hope you continue updating us in the future. The amount of oil you collect in the can, should be an indication of the problems we will experience as time passes.

I have seen YouTube videos of people finding catch cans completely full of oil which was collected between one oil change and the next. Hopefully that was on earlier DI engines and not representative of the engine in our RDX's.

horseshoez

iTrader: (2)

Wow, not sure what you've been reading, but your treatise above needs a little more research.

What is conflicting about cleaning the back of intake valves vs. exhaust valves? I ask because while exhaust valves are typically only subject to clean dry exhaust, intake valves are subject to all manner of crank case oily blow-by gases mixed with recirculated exhaust gas. Long story short, intake valves on direct injection engines will accumulate many orders of magnitude more crap than exhaust valves and will need cleaning (see below); as for exhaust valves, not a problem.

The fact is, unless engines with direct engines either A) have their intake valves cleaned periodically, or B) the engine manufacturer opts to use a dual injector approach per cylinder (i.e. one DI and one upstream of the intake valves ala. Toyota), the valve train will not last compared to conventional port-style injected engines.

Wander

I'm calling BS on the DI fear mongering, at least in regard to Honda/Acura.

I traded in a 2016 Honda Pilot at about 87k miles, with the same 3.5L DI V6 as the current MDX and other Acura vehicles. The engine was as strong and smooth as the day I bought it. And no, the intake valves had never been cleaned, aside from "blowing out the carbon" on the Interstate once in a while.

OTOH the 9-speed ZF transmission was an annoying POS. Couldn't wait to be rid of it.

horseshoez

iTrader: (2)

Call BS all you want, unless you took a look at the back side of the intake valves you have absolutely no way of knowing how bad things were.

losiglow

iTrader: (1)

Good to know. Maybe the V6 doesn't have as much blow by. Not sure. But blowing out the carbon via the "Italian tuneup" may cleanse the combustion chamber a bit but it won't do anything for the intake valves. Depending on the design, it's entirely possible that the intake valves could be in pretty sore shape yet the engine still running decently. If that's the case, maybe it doesn't matter as much if your intake valves get coated in gunk. Still, it's pretty much inevitable that carboned up valves are eventually going to result in misfires or performance problems. I haven't heard any horror stories about the Honda V6 engines but there are a few of the Earth Dreams I-4's that have had reported problems. Specifically in the Fit and CRV. And a ton of other engines from VW, Subaru and Kia. And pretty much every other manufacturer with DI.

That direct and port injection design that Toyota and Ford are putting out seems pretty promising. It adds yet another thing that can go wrong since you now have two injection systems. But I guess that's the lament of all new cars. They're much more complicated than they were back in the carbureted days. I don't necessarily miss those days though It wasn't much fun starting my 2nd gen Camaro in the winter.....

Madd Dog

My 2008 BMW 535i had a turbo and DI. After 11 years and ~ 120K miles, I had no symptoms of fouled intake valves. My indy advised me to wait until there were codes, or a drop off in performance, and I experienced neither. The BMW forum was filled with comments about the need for walnut blasting, and it was a real back and forth.

My guess is that those who really pushed their engines, based on the way they talked, might have encountered problems before the rest of us, or were maybe that much more hyper about it.

catalytic_ca

The current style of direct only injection system is likely just a temporary phase as manufacturers update their designs to solve for those issues. As mentioned above, Ford and Toyota have introduced dual injection systems (port and direct) in response. Other manufacturers are following suit. Ideally, one would purchase a car with a dual injection system. But if not, using a fully synthetic oil, preferably one with a lower NOACK %, will help. Catch cans will too, but I'm a bit wary of installing one due to potential issues with the warranty. Here are a couple good videos on the subject:

Wander

This is true, but unless it's causing performance or driveability problems, it doesn't really matter what it looks like.

FWIW I did most of my own oil changes with Mobil 1. But I wouldn't say I babied the thing otherwise. More like flogged it everytime it was foolish enough to take me to the Rockies.