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Has any manufacturer mastered direct injection? I have been reading about carbon buildup on the intake valve stems of multiple auto makers. Engines needing disassembly at 30,000 miles for cleaning. I appreciate the better fuel economy these engines generate but.............
Has any manufacturer mastered direct injection? I have been reading about carbon buildup on the intake valve stems of multiple auto makers. Engines needing disassembly at 30,000 miles for cleaning. I appreciate the better fuel economy these engines generate but.............
what engines are you talking about that need to be disassembled and cleaned after only 30,000 miles?
what engines are you talking about that need to be disassembled and cleaned after only 30,000 miles?
I was thinking the same thing. I have never heard of a vehicle having to have their engines taken apart to be cleaned, much less at 30,000 miles.
All engines produce carbon. Trying to find one that does not is like trying to find a cloud without water vapor. There are many fuel cleaning additives that you can find on the shelf at Autozone or even walmart. I try to put some of that through semi-frequently, but I have an F-150 that tends to break spark plugs due to carbon build up (unrelated to DI).
EDIT: Are you perhaps thinking of engines that need extensive cleaning after long long periods of no oil changes?
With a Direct Injection engine, it is even more important than with other fuel injection systems to use gasoline with a high level of detergents.
Those who say that "gasoline contains enough detergents to keep your injectors clean" are apparently unaware that revisions to existing EPA regulations during the GW Bush administration allowed petroleum companies to drastically reduce the level of detergents. And, apparently, the current administration has not seen fit to restore the earlier--higher--detergent requirement for gasoline.
The result of this reduction in detergent levels was the creation of the Top Tier gasoline standard by GM, Toyota, BMW, & VW.
In order to qualify for Top Tier certification, a gasoline brand has to pass a series of stringent tests, and to maintain a higher level of detergents than The EPA requires.
If you go to the Top Tier site, it will show you a list of the qualifying gasoline brands in your area.
Luckily, the list is longer than it used to be! http://www.toptiergas.com/retailers.html
When Shell introduced their new detergent formulation a few years ago, I recall reading that it was done as a result of the advent of Direct Injection technology.
And, if you have Costco gas stations in your area, take note of the reality that Costco gas now meets Top Tier standards, and is almost always less expensive than other brands. A true win-win.
Porsche had direct injection from 69 to 73 on the 911. It was a mechanical pump injector. I drove a 73 for 90,000 miles and never had a problem with it. With stricter EPA standards, the switched to Bosch CIS
Direct injection for gas engines is not new. It has been considered a design defect since it was first used. There's no way to control combustion deposits even using top tier gas. The issue with todays engines is that most use a EGR system. This system recycles the deposits back into the combustion chamber and they form on the intake and intake valves. Because no gas ever sees the intake like with a sequential or throttle body injection, deposits build and there's no way to remove them except manually. There are several trial units out now that use crushed walnut shells to beat the deposits off of the intake and intake valves but it comes with issues that they are working on. Here's an Ecoboost 3.5 valve stem at 25,000 miles.
FWIW, there are several auto makers that are recommending the intake come off of the engine for manual cleaning. Mini is one and they suggest it be done every 10,000 miles at owners expense. Cost....about $1,000.00.
BMWs with direct injected turbos are starting to show heavy carbon deposits at relatively low mileage. They have instituted a new cleaning procedure that requires removal of the intake manifold and shot cleaning the valves with walnut shells. Major PITA.
BMWs with direct injected turbos are starting to show heavy carbon deposits at relatively low mileage. They have instituted a new cleaning procedure that requires removal of the intake manifold and shot cleaning the valves with walnut shells. Major PITA.
There were problems with those turbos from the start as I recall. Went to a single mid production run.. I stick with naturally aspirated.
Hyundai pretty much uses GDI in all of their vehicles now, and so far I haven't heard of any problems related to carbon buildup. Some Elantra owners have complained of a cloud of black smoke when they floor it to pass someone, but it hasn't affected engine longevity that I know of.
I was thinking the same thing. I have never heard of a vehicle having to have their engines taken apart to be cleaned, much less at 30,000 miles.
All engines produce carbon. Trying to find one that does not is like trying to find a cloud without water vapor. There are many fuel cleaning additives that you can find on the shelf at Autozone or even walmart. I try to put some of that through semi-frequently, but I have an F-150 that tends to break spark plugs due to carbon build up (unrelated to DI).
EDIT: Are you perhaps thinking of engines that need extensive cleaning after long long periods of no oil changes?
You can dump all the fuel-cleaning additives you want into the tank but it won't do much good if the fuel never contacts the intake valves due to being injected directly into the combustion chamber.
Carbon buildup on intake valves has indeed been a major issue for many DI motors for exactly this reason.
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