Jonny888

So I'm pretty much set on getting a 2016 sh awd tech as there's not really any other car in my price range and preference.

I just realized that the TLX's engine is direct injection, which is known to have carbon build up issues unless a work around has been achieved, like Toyota's port injection included with direct injection. So to you owners, have any of you guys experienced build up, or has Honda worked a fix for it to clean the build up? Am I going to have to anticipate a cleaning bill every so often like the 2015+ WRX and others?

dezymond

I've always been told if you're using quality gasoline then you should be ok. I personally stick to Top Tier gasoline.

RDX10

This is not exactly true. The carbon buildup issue is an inherent design flaw that is not curable via the type of fuel or various fuel additives. Using better quality fuel MAY slow down buildup, but it will not eliminate it. Truly the only way to eliminate it is to remove the valve cover and manually clean out the deposits every 50k or so.

Some engines are more prone to buildup than others though, like the VW 2.0t and 3.2fsi engines are notorious for this. I don't think I have read of Honda engines with this issue yet. But it is still early.

The port injection "washes" the carbon off of the back of the valves where in a pure DI engine there is no way to do that without physcially cleaning it.

I can see down the road carbon cleanup being a routine 60k maintenance item.

Jonny888

Thanks, I've been looking around some old accord forums and I haven't really seen anything other than questions on the topic.

rxr

As someone who's also concerned about the long term reliability of this direct injection engine (3.5L V6), I have also spent a lot of time looking up this issue and there is literally nothing on any Honda or Acura forums where a user has complained about actual issues related to DI or removed their intake manifold and provided pics. Honda has implemented direct injection rather late in the game and one can only hope they learned from the horror stories of carbon buildup on early Audi and VW GDI engines. I've also read somewhere that Honda used a different orientation of the fuel injectors and spray pattern for their GDI engines that supposedly helps reduce buildup but that's just from other users claiming to have spoken with Honda engineers so it's dubious. Just got to wait and see. I've seen pics of a WRX 2.0 GDI that had terrible build up at only 15k miles that needed to be removed.

RDX10

Doesn't the accord use a non DI V6?

thisaznboi88

iTrader: (7)

Install a water meth kit. Problem solved

BEAR-AvHistory

There is no fix. That said you can slow down the effect by installing a catch can on the EGR hose. Turbos are more effected but N/A engines will still coke up.

RDX10

I completely forgot about a catch can. Apparently they help tremendously but not enough in all cases.

accord1999

The MDX with a DI 3.5 started selling about a year earlier than the TLX and I haven't read any issues of carbon buildup on it yet. There's also been large numbers of DI 4-cylinder engines sold now and there doesn't seem to be any carbon issue with those either so it's possible Honda has done the necessary engineering to avoid the problem.

Jonny888

I think it's the v6 with DI, not 100% sure though. The closest I've read about a problem is the DI with the first gen VCM causing misfiring and they had found some build up problems.

jshaw

GM has been using DI since 2008, without any problems.

Honda has been using DI since 2012, with similar result (they did first deploy the technology on a JDM car in 2004, results unknown, since its emissions levels, while compliant in Japan, were a bit high for the US. As a result, it was never released in the US).

VW has used DI, with lots of carbon buildup.

In addition, VW claimed they have clean diesels. Where did that get them?

I think I have found the source of the problem.

BEAR-AvHistory

GM is not immune to the problem but they do well at reducing it without going to dual injectors. The have their own tech bulletins & a service routine for carbon on the valves.

GM Recognizes the issue:
PIP5029C: Engine Misfires Due To Major Carbon Deposits On The Intake And Or Exhaust Valves - (Apr 23, 2013)

This is a typical post:
"I am not an expert but I am rigorously following the $200 induction cleanings that my GM dealer suggests for the 3.6 DI, and when the warranty is over I will switch to a catch-can. There is too much documented proof out there to suggest otherwise."

Toyota has the best solution so far two sets of injectors. One for the normal DI function & a second set back in the intake tract to spray fuel onto the rear surfaces of the valves where the carbon forms.

Mr Hyde

I own a direct injected Audi 4.2 V8. Catch cans, top tier gas, "italian tune-ups" etc, etc do not prevent buildup. Some think some oils may slow the buildup, but not prevent it.

I've paid for a manual valve cleaning once about 15k ago, and will probably do another in another 5k or so.

The only real way to prevent it is what Lexus designed, and I believe Audi has now adopted as well which is a combination of direct, and port injection.

thisaznboi88

iTrader: (7)

Like I said water math or straight water injection to clean the im, ruuners, valves etc. Ran it on an n.a car before going turbo without issues. Cleaned out all the egr crap also.

TacoBello

I think this carbon build up issue is blown way out of proportion. Wifey's car has 70k miles on it, never had any special engine cleaning done, only runs on regular fuel (doesn't need premium), and haven't had a single issue to date. While I'm sure there is carbon build up occurring, due to DI, I don't think it's as bad as it is made out to be. Forums always blow the smallest issue out of proportion "omg the car will explode!! "

dezymond

Agreed.

Forums, especially ones like AZ, never really hear about the cars running fine, but the ones with problems. It's a community mainly for help after all, no one asks for help with a perfectly working car.

csmeance

Carbon buildup will occur, it really depend on driving style, oil change intervals and also the design of the engine. With a bit of seafoam in the intake every oil change I don't foresee an issue. I do the same with my 760 and no issues yet with 120K.

dezymond

For those that don't know about SeaFoam, this guy does a great demo of it. I have yet to try it myself.

RDX10

Mr Hyde

Its been tried on the RS4, and didn't do much to prevent the buildup.

Been discussing this since purchasing my RS 7+ yrs ago. On that car due to its design, the carbon can interfere with the intake flaps present in its manifold, and also cause CELs. Over time, it can rob HP as well, so many people just get cleanings to put a little kick back in its step, not due to concerns of any kind of failure.

Many have tried induction cleanings, but they haven't been enough to cut through the rock-hard buildup. Chemical cleaners, manual agitation, and walnut blasting have been the only things to yield nice clean valves.

TacoBello

DI engines could very likely be different, however, back in the good old days, when swapped B16 and B18 engines in Hondas were all the rage, I had a close friend, a ceritified Honda mechanic, do all the maintenance on my civics. I remember him pulling the head off one engine to replace the headgasket and he said "look how clean the top of your pistons are. Do you know why they look so clean? It's because you drive and rev the snot out of the engine, the way it was supposed to be driven. People that baby these engines end up with a lot of carbon build up and that can cause troubles. The carbon can break off and cause a valve to stay open and burn it out. By utilizing VTEC (driving above 5000rpm) regularly, you're keeping your engine looking nice on the inside"

Well, I don't know how true any of that was. This was going back about a decade. But I wonder if the same would hold true for DI engines?

Mr Hyde

That all applies to Port Injection, but with Direct Injection moving the injector makes everything different. Trust me, myself and many other RS owners use every bit of the 8400 RPM redline.

After the combustion cycle, over time, sticky vapor byproducts end up coating the backside of the valves. You can also get some buildup from around the valve stems as well. In Port Injection, fuel continually washes the backside of the valve, and keeps it clean. In Direct injection, since the fuel is injected right in the combustion chamber, there is nothing washing over the backside of the valves, that sticky residue just builds up tiny bit, by tiny bit over several thousand miles coating the back of the valves, and in the case of the RS, the port separators, etc, etc as well.

Using low quality fuels, oil, and prolonged oil change intervals (DI engines suffer more oil fuel dilution as well) will just accelerate the issue, but nothing really prevents it.

Not my car, but check this site out. http://redlinespeedworx.com/audi-rs4-carbon-cleaning/

Mine was nowhere as near as bad, but that buildup obviously interferes with flow around the valves.

BEAR-AvHistory

Engine usage, injection type & N/A or boosted are the main contributors to the buildup. The DI engines have no way of cleaning the valves so they will coke quicker than port injection or DI/PI combo engines.

The more an engine is pushed the more oil vapor goes into the EGR system due to increased crankcase pressure. Boosted engines increase crankcase pressure more than N/A engines so they will coke quicker.

Catch cans do help quite a bit. The 335is was raced quite a bit & driven quickly on the street. Needed a walnut blast a 25K miles. Installed a catch can & engine was still strong when I sold it. Dumped the can at about 3 month intervals.

The COYOTE in the Cobra runs without an ERG system. Crankcase pressure relief was through two hoses from the old ERG take off points to a single catch can then to a dump tube releasing the cleaned vapor to atmosphere. Can filled in two months on a general basis. These engines are noted for excessive vapor out the passenger side valve.

As an experiment have replaced the system with push in filters in the coil cover ERG pick up points. Not enough miles to tell if they are a better choice. The do look a lot better.

Saintor

Its V6 has not DI, only the 4cyl.

thisaznboi88

iTrader: (7)

kill it with FIRE!! but not really

csmeance

Almost ALL of Acura/Honda Lineup now uses Earthdream engines which come with Direct Injection, 4 Cyl and 6 cyl.

Carbon buildup is going to happen, it's a byproduct of combustion. Less oil in the combustion chamber means less "carbon" that can be burnt and coat the insides of your engine. Agree 100% with a catch can installation.

Saintor

They may be called Earthdream but again, the V6 in the 2016 Accord or Odyssey has no direct injection, even the Touring versions.
Honda Worldwide | EARTH DREAMS TECHNOLOGY
https://www.honda.ca/accord_sedan/specs

Just a question of time...