A premium fuel version of this engine have been used three Acura models for the last two years with no reported carboning that I can find. Nor have I found carboning reports in DI 4 cylinder Accords that go back to 2013, many of which have 70k + miles according to the drive accord forum. I think Honda was well aware of the DI issues with carboning when they designed these newer DI systems. EGR has also been thought by some to be part of the problem. It's interesting that the 3.5 DI Honda draws its EGR supply from downstream of the cat so there's hardly any complex hydrocarbons from that source being breathed in the intake.
Is direct injection carbon buildup a problem in the 3.5?
I moved to my Ridgeline from a VW with a 2.0l turbo engine. It had direct injection, which meant valve cleaning gasoline additives never passed over the valves. Thus, the valves, which also had crankcase ventilation gasses passing over them, were vulnerable to carbon buildup.This often caused misfiring at idle, maybe more serious issues, requiring periodic costly valve cleaning.
Honda says we have direct injection in our Ridgelines. Do Ridgeline engines have carbon buildup issues related to direct injection?
Honda says we have direct injection in our Ridgelines. Do Ridgeline engines have carbon buildup issues related to direct injection?
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I would hope that Honda has this covered but all we can do is use top tier gas as Honda recommends.
On the VW side this was a big deal and gas made zero difference. Gas is directly injected into the cylinder, so the cleansing qualities of the additives never flowed over the intake valves. There were only two fixes: periodic walnut bead blasting of the backside of the valves (~$450) or, nonpublished by VWoA from an internal patent, periodic runs for a minimum of 20min at 3000+ rpm to burn it off. I can tell you from experience that actually worked very well and avoided unexpected costs.I would hope that Honda has this covered but all we can do is use top tier gas as Honda recommends.
I rarely get above 1500rpm in my Ridgeline commute, which make makes me concerned about buildup. I'm hoping Honda has addressed this through some means so I don't have to schedule regular high rpm runs into the next county and back...
I hope that's the case. My GLI was recirculating straight from the crankcase...A premium fuel version of this engine have been used three Acura models for the last two years with no reported carboning that I can find. Nor have I found carboning reports in DI 4 cylinder Accords that go back to 2013, many of which have 70k + miles according to the drive accord forum. I think Honda was well aware of the DI issues with carboning when they designed these newer DI systems. EGR has also been thought by some to be part of the problem. It's interesting that the 3.5 DI Honda draws its EGR supply from downstream of the cat so there's hardly any complex hydrocarbons from that source being breathed in the intake.
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I would think the fact that your VW was a turbo exacerbated the carbon buildup issues.
All Direct Injection engines have carbon buildup on the intake valves. Honda cured this by leaving the throttle barrel injector to provide the idle speed fuel and help start the engine and gas to clean the intake valves.
It appears that all the newer DI engines have that feature to keep the problem that the first DI engines (Cadillac was really bad) experienced. By putting some fuel the old fashioned way keeps the intake valves clean(er).
It appears that all the newer DI engines have that feature to keep the problem that the first DI engines (Cadillac was really bad) experienced. By putting some fuel the old fashioned way keeps the intake valves clean(er).
It has to do with the detergents in gasoline, at specific amounts/levels.What is top tier gas?
Home | Top Tier Gas
I'm aware of the use of "dual injection" (port and direct on the same engine) by Toyota/Lexus and Audi as far back as 2005. I know for a fact that the Subaru BR-Z/Scion FR-S and the 2016 Tacoma use this setup. I'm unaware of a Honda application that uses direct injection with any additional injector type. Do you have an example?All Direct Injection engines have carbon buildup on the intake valves. Honda cured this by leaving the throttle barrel injector to provide the idle speed fuel and help start the engine and gas to clean the intake valves.
It appears that all the newer DI engines have that feature to keep the problem that the first DI engines (Cadillac was really bad) experienced. By putting some fuel the old fashioned way keeps the intake valves clean(er).
This is great, glad to hear. Now I will agree that 'good gas' is important!All Direct Injection engines have carbon buildup on the intake valves. Honda cured this by leaving the throttle barrel injector to provide the idle speed fuel and help start the engine and gas to clean the intake valves.
It appears that all the newer DI engines have that feature to keep the problem that the first DI engines (Cadillac was really bad) experienced. By putting some fuel the old fashioned way keeps the intake valves clean(er).
I googled your (very good) question some. So far as I can see, the use of an additional injector in or near the throttle body was limited to older vehicles such as Bosch mechanically injected Euro cars, certain Toyota EFI systems in the 80's and 90's and some Honda Civic pre 2005's. All these systems used this injector for cold start/idle enrichment only.I'm aware of the use of "dual injection" (port and direct on the same engine) by Toyota/Lexus and Audi as far back as 2005. I know for a fact that the Subaru BR-Z/Scion FR-S and the 2016 Tacoma use this setup. I'm unaware of a Honda application that uses direct injection with any additional injector type. Do you have an example?
The dual system in the FR-S, BR-Z, 3.5 Tacoma, 3.5 Lexus GS and 4.6 LS 460 is more interesting. These systems address a weak point in pure DI designs which need the intake port to induce a strong swirling motion to the intake air create a homogenous mixture in the cylinder. This limits breathing at very high RPM. Port injection mixtures can be homogenous without this energy robbing induced swirl. These engines use the port or direct injectors separately or together, depending on conditions. Cold starts use direct, injected during the compression stroke to purposely create a stratified mixture to light off the cats as quickly as possible. Warm-up uses both, cruising uses DI only and heavier or WOT uses both injectors.
The Honda DI systems in our RL's, according to Honda's press kit, inject on the compression stroke during cold start. Like the Toyota system, this makes a stratified mixture which is richer near the spark plug. When ignited, this mixture makes a nice hot high volume exhaust to quickly heat and light off the cats. At cruise and up to WOT, injection is on the intake stroke.
I question the idea that port injection prevented carboning on intake valves in all cases. In my years in and around the auto service bizz, we saw plenty of nasty looking carboned up intake valves (and ports) in carbed, throttle body injected, and port injected engines. Old port injected VR 6 VW's were really bad. It actually takes a fairly thick deposit to throw a code or noticeably affect performance on most engines.
Thanks for the interesting research, Robert. I started having problems in my GLI at about 20k miles, but my average speed for probably 90% of those miles was around 17mph, lots of idling. (16 traffic lights and horrendous sloooww traffic each way on my work commute. VW said the $400+ treatment for misfires at idle were not covered by warranty, even though there were many cases of the same issue putting the car into 'limp mode'. I had already been reading reports on VWVortex about doing a high rpm run to burn off carbon. I was skeptical, but did a 20 mile run up I-49 and back, and the miss at idle went away. I continued to do that with good results once every couple of months until I traded for my RL.I googled your (very good) question some. So far as I can see, the use of an additional injector in or near the throttle body was limited to older vehicles such as Bosch mechanically injected Euro cars, certain Toyota EFI systems in the 80's and 90's and some Honda Civic pre 2005's. All these systems used this injector for cold start/idle enrichment only.
The dual system in the FR-S, BR-Z, 3.5 Tacoma, 3.5 Lexus GS and 4.6 LS 460 is more interesting. These systems address a weak point in pure DI designs which need the intake port to induce a strong swirling motion to the intake air create a homogenous mixture in the cylinder. This limits breathing at very high RPM. Port injection mixtures can be homogenous without this energy robbing induced swirl. These engines use the port or direct injectors separately or together, depending on conditions. Cold starts use direct, injected during the compression stroke to purposely create a stratified mixture to light off the cats as quickly as possible. Warm-up uses both, cruising uses DI only and heavier or WOT uses both injectors.
The Honda DI systems in our RL's, according to Honda's press kit, inject on the compression stroke during cold start. Like the Toyota system, this makes a stratified mixture which is richer near the spark plug. When ignited, this mixture makes a nice hot high volume exhaust to quickly heat and light off the cats. At cruise and up to WOT, injection is on the intake stroke.
I question the idea that port injection prevented carboning on intake valves in all cases. In my years in and around the auto service bizz, we saw plenty of nasty looking carboned up intake valves (and ports) in carbed, throttle body injected, and port injected engines. Old port injected VR 6 VW's were really bad. It actually takes a fairly thick deposit to throw a code or noticeably affect performance on most engines.
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Thanks for the link.
Just wanted to make sure this wasn't some gimmicky thing.
My Honda mechanic friend showed me an Earth Dreams engine (in an Accord) that the intake valves were badly coated at 75,000 miles (a courier vehicle for a drug store - lots of starts and stops) - he had to clean all the intake valves and replace the injector that provides some fuel for to clean the valves - I suspect that all Earth Dream engines have that feature.
The valves get coated by the oil/gas/air mixture sent to the intake by the PCV valve(s)(some cars have one on each side of the V6 or V8 or horizontally opposed engine). The really best cure is to put something to trap the oil after it leaves the PCV valve and before it gets to the air intake side. Cismo talked about this a few years ago and said he would put one on his DI engine (getting old and my memory aint what it used to be. I think it was Joe.)
The valves get coated by the oil/gas/air mixture sent to the intake by the PCV valve(s)(some cars have one on each side of the V6 or V8 or horizontally opposed engine). The really best cure is to put something to trap the oil after it leaves the PCV valve and before it gets to the air intake side. Cismo talked about this a few years ago and said he would put one on his DI engine (getting old and my memory aint what it used to be. I think it was Joe.)
M2C
I believe that the carbon is coming from the PCV valve system.
The Carbon ( basically cooked oil vapor) that is collecting on the intake valves is from the crankcase ventilation system. That is why the type/certifiation of oil recommended by the Manufacture is important to be adhered to. They know that the carbon build up is a issue with ALL DI systems but the benefits must outweigh this issue of build up. Better emissions, fuel economy for example.
While some may be coming from the EGR valve it is a small amount IMO.
Catch Cans are the best defense against this issue. It is basically an air/oil separator that catches some of the oil en-route from the crank case to the intake.
Oil Catch Cans | Everything you need to know and more!
Since the fuel never touches the back of the intake valve due to it being injected directly into the combustion chamber, spending $ on a higher grade of fuel with more cleaners is just $s out the tail pipe.
Disclamer. My mastery of writing leaves a lot to be desired so Please over look that.
I believe that the carbon is coming from the PCV valve system.
The Carbon ( basically cooked oil vapor) that is collecting on the intake valves is from the crankcase ventilation system. That is why the type/certifiation of oil recommended by the Manufacture is important to be adhered to. They know that the carbon build up is a issue with ALL DI systems but the benefits must outweigh this issue of build up. Better emissions, fuel economy for example.
While some may be coming from the EGR valve it is a small amount IMO.
Catch Cans are the best defense against this issue. It is basically an air/oil separator that catches some of the oil en-route from the crank case to the intake.
Oil Catch Cans | Everything you need to know and more!
Since the fuel never touches the back of the intake valve due to it being injected directly into the combustion chamber, spending $ on a higher grade of fuel with more cleaners is just $s out the tail pipe.
Disclamer. My mastery of writing leaves a lot to be desired so Please over look that.
Ford is also using dual injection on the latest 3.5L Ecoboost engine. A direct injector and a port injector at each cylinder.I'm aware of the use of "dual injection" (port and direct on the same engine) by Toyota/Lexus and Audi as far back as 2005. I know for a fact that the Subaru BR-Z/Scion FR-S and the 2016 Tacoma use this setup. I'm unaware of a Honda application that uses direct injection with any additional injector type. Do you have an example?
2017 Ford F-150 Receives Upgraded 3.5-Liter EcoBoost Engine - PickupTrucks.com News
Like you, I never heard of this approach being used on the current generation honda 3.5L Earthdreams motor.
Hmmm. I'll keep searching. I'm still trying to find an Earth Dreams application that includes anything other than direct injection. I found these detailed articles on the 2.4L and 3.5L Earth Dreams engines on Ward's Auto, but neither mentions a fuel path other than the direct injection system.My Honda mechanic friend showed me an Earth Dreams engine (in an Accord) that the intake valves were badly coated at 75,000 miles (a courier vehicle for a drug store - lots of starts and stops) - he had to clean all the intake valves and replace the injector that provides some fuel for to clean the valves - I suspect that all Earth Dream engines have that feature.
Dreamy Technology Makes New Honda 4-Cyl. Stand Out | Technology content from WardsAuto
Honda 3.5L SOHC V-6 | Technology content from WardsAuto
I was curious and took a look at some engine parts diagrams at bernardiparts, and no "extra" injector is shown. BTW, if you ever need a new DI injector, it will cost you $277 MSRP.
I think Honda is minimizing carbon buildup by tweaking valve timing and improving their crankcase pollution controls.
I think Honda is minimizing carbon buildup by tweaking valve timing and improving their crankcase pollution controls.
Have not been able to find anyone commenting on their having installed a catch can to prevent/reduce the amount of oil being sucked back into the intake, As noted in this topic, direct injection makes it an even worse condition. I have installed them on a 2005 Vette and a 1987 Buick GN. I continue to be amazed at the amount of oil I am able to collect in the can.
Admittedly the GN is a turbo with major boost and such, these engines are the first to benefit from installing a catch can.
As with the Muzzler, the addition of a catch can on the Honda 3.5 can be debated all day long. But from my perspective, both modifications are not modifying the operation of the engine in any major way and can be easily removed. I say that not yet really knowing where the 2017 Honda 3.5 PCV valve is located ...
Admittedly the GN is a turbo with major boost and such, these engines are the first to benefit from installing a catch can.
As with the Muzzler, the addition of a catch can on the Honda 3.5 can be debated all day long. But from my perspective, both modifications are not modifying the operation of the engine in any major way and can be easily removed. I say that not yet really knowing where the 2017 Honda 3.5 PCV valve is located ...
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