RCJD

Is this true? See link below.

I was thinking of upgrading to TLX but now Im thinking twice. Rather keep the 3.7L engine?

https://autos.yahoo.com/news/direct-injection-engines-improve-performance-save-fuel-price-193000698.html

justnspace

iTrader: (1)

it's an inherit design where carbon builds up.
now, different manufactures have different ways of solving said issue.
we dont know if Honda's DI engine has this design flaw.

csmeance

I had to get my 760's engine cleaned via walnut shell blasting at around 105K and the difference it made was noticeable. I've heard of a lot of 335 and 535 owners doing the same at higher mileage to get rid of engine problems and to restore power.

The main issue is that fuel isn't spraying before the combustion chamber so there isn't any way to get the intake valves clean. With EGR systems this only gets made worse. BMW has been replacing injectors left and right on 2009+ 750's because the injectors are failing in 10-15K miles due to buildup.

Easiest solution, have a port injecting some fuel before the valves and do the rest of the injection in the chamber.

ttribe

Had my intake valves on the 335i cleaned at around 65k. I was starting to get some flutter and a couple of mis-fires. Cleaned, the engine was like new. Small maintenance price to pay for the additional power, etc.

thisaznboi88

iTrader: (7)

inject water/meth. problem solved

fsttyms1

I really wouldnt say its something that you should consider not buying because of.

YeuEmMaiMai

yeah periodic spraying something like Seafoam into your intake to clean your intake valves is not something your average motorist is going to do... but the dealer will come to the rescue for a few $$$..

fsttyms1

Ive been doing it to my dads 2010 Genesis once a year. Slowly spray in one can of seafoam once a year and his car is still butter smooth and mileage hasnt been effected one bit in over 160k miles.

csmeance

would using "deep creep" from the makers of seafoam be easier since it's an aerosol?

SuperTrooper169

iTrader: (2)

The Mazdaspeed6s had one of the very first DI engines sold in the U.S. and after only 40k miles or so the carbon built up so much in the EGR tube on mine that it threw a CEL. It was a relatively easy fix, just took the tube off and saturated it with brake cleaner and used a pipe brush to get the build up out of it, as well as cleaned out the EGR valve itself. There's pros and cons to each engine design so it wasn't the end of the world to deal with that. For the performance the engine had while giving pretty decent MPG it was a small thing to deal with. As others have said Seafoam is another way to combat it.

YeuEmMaiMai

you got to admit though that most of us here are mechanically inclined to do so.... and we are significantly outnumbered by people who do nothing more than gas and go...

fsttyms1

Might be, but i prefer the can of it. Then i pour it into a nitro fuel filler (used for my rc truck) with the tip squished down and squeeze/spray it into the intake so that i can better regulate how much comes out. I find the deep creep just doesnt come out with enough volume fast enough.

NSXNEXT

iTrader: (2)

And you just love to send a huge cloud of white smoke into your neighborhood.

fsttyms1

Well DUH.......

Reorge

This is why Honda waited so late getting into the DI game. They were criticized by some for waiting but now we know DI has some inherent issue(s) that are not 100% solved by the auto industry. I actually purchased my 2012 after reading reports that an Acura V6 DI engine was soon to be introduced.

As far as getting a TLX .... new technology is always a risk. This engine has been in the RLX since 2013 so perhaps there is enough information out there for you to make a sound decision.

Perhaps the intake valve fouling problem can be solved by some kind of periodic cleaning.

charliemike

This is fixed by having two injection points. Cars with a single injector per cylinder get the carbon buildup. Supposedly having direct and port injection will help burn off the oil before it gets a chance to burn in the cylinder.

vietxquangstah

iTrader: (7)

Toyota came up with a clever solution to this problem and it is called D-4S injection. It is a combination of Direct Injection & port injection. It is utilized in the FRS/BRZ

YeuEmMaiMai

I doubt it was Toyota only since it is powered by a SUBARU boxer

vietxquangstah

iTrader: (7)

As far as I know Toyota are the ones that came up with it. I could be wrong but everywhere you search and read about the D-4S or D-4 system you always see it say " Toyota development"

There are other versions that are also used in other toyotas like the IS350 which is also direct injected. That motor has been around for years and you don't hear any complaints about carbon buildup on the pistons.

If you are so sure that Toyota aren't the only ones that came up with it you would research into it and come back with the results to share with everyone else.

Technical information on the Toyota D-4S system - Scion FR-S Forum | Subaru BRZ Forum | Toyota 86 GT 86 Forum | AS1 Forum - FT86CLUB

JS + XES

iTrader: (1)

D-4S system was indeed developed by Toyota. They just incorporated to the Boxer engine for Toyobaru.

justnspace

iTrader: (1)

pwned.

jhumbo

iTrader: (1)

Kia/Hyundai have a recommended maintenance item of "fuel system cleaning" every 30k miles for their GDI engines. From what I understand from talking to the Service reps, this is basically a fuel additive.

fsttyms1

Which would do nothing due to it being sprayed into the cyl and not the intake before the intake valve. Any chemical/Cleaning has to be done in the intake side, not the at the injector

thisaznboi88

iTrader: (7)

water methanol injection would solve your issue. ;p

http://www.aquamist-direct.com/

jhumbo

iTrader: (1)

Arggh. Makes sense. So in general how difficult is cleaning injectors?

ttribe

It's not the injectors that need the cleaning, it's the intake valves. Because the fuel is no longer being sprayed onto the top of the valve (where fuel detergents can clean away deposits), the gunk builds up on the valve itself. A popular cleaning method with the BMW crowd is walnut blasting, but it is relatively pricey (of course). I found an independent shop near me who gives the valves a chemical bath, then scrubs the deposits off manually; it was much cheaper and it was plenty effective.