Subaru/Toyota D-4S: The Superior Gasoline Direct Fuel Injection System.

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[@robertshunter]

The number of manufacturers which didn't see the potential pitfalls of DI still amazes me.

[@valdius85]

They "see it". It is customers that don't do research and don't complain... :)

[@zacharydehart5597]

Planned Obsolescence...

[@ChadRazorback]

You think they didn't see the $500+ service they could try to add to every car they sell?

[@robertshunter]

@@ChadRazorback I've seen the warranty costs they've had to pay out.

[@stuntmonkey00]

They see it, they just decided that it was good marketing to kick the can down the line past the warranty period. In the short term they meet their emissions targets and get to put a nice mpg number on the window sticker to get the sale. That said, there seems to be a lot going on with exhaust gas management to at least ameliorate some of the deposit and to at least extend the interval until the service is necessary.

[@matthewmaca6675]

Kinda the best of both worlds with direct and port

[@jbradley920rox]

Meh. Until it's time to deal with that carbon issue

[@Leon1982db]

@@jbradley920rox the port will help keep them clean

[@DonnerPassWhisky]

This is the best description of this subject I have ever seen. Detailed and specific yet using language everyone can understand. Thanks.

[@Rainproof1]

Absolutely one great video! I hope to see an technology agreement between Toyota and Subaru.

[@werecow68]

This is the same system on the 2.0L Toyota uses on higher Corolla trims and other vehicles. Great video Robert, thanks for showing us the inside.

[@JenniLudes]

You just gave me another reason to hang on to my "old tech" 2019 STI...port injected fuel on the EJ. Of course, I knew this when I bought it and frankly, it was one of the reasons for buying it. My 2016 Crosstrek's had to have this cleaning service and it's not cheap and not something I've taken on as DIY. Great video!

[@artilleryisbetter]

Shouldn't be an issue for FB

[@jonk6137]

Damn Robert you should’ve worn a freaking lab coat in this video. Lol maybe a mr subi lab coat thanks for the video and engine lesson.

[@FanatikBuilds]

While admittedly a bit complicated having two separate systems, it is nicely packaged and does make sense! If we have to have GDI for efficiency, why NOT at least throw some port injectors on there as well for startups and periodic valve cleaning cycles! 🤷🏼‍♂️ Great video man 👍

[@Central-Scrutinizer]

This should be on all Subarus!

[@alanberry2930]

Excellent video and thorough explanation so that even a layman like me could understand! 👍🏻

[@DaddyBear1971]

Thanks for doing such an indepth job on this video, Especially great was a look inside the engine and showing the high pressure pump and rails.

[@christopherdimotsis1024]

It’s also important to note that in lower load times port injection is more efficient and this system adjusts between all direct a mix and all port. But these conditions are dependent on engine speed and load. For instance cruising on the highway, the engine would be low speed with a low to moderate load, port injection is best then but the opposite where you are flooring it you get the best performance with only direct injection. If you go between these you would get a varying percentages of port to direct.

[@jordanlatta]

I assumed the opposite. I thought the point of GDI was to safely achieve ultra-lean mixtures by only using direct injection under low load, like when you lift the throttle, and that's why gdi pistons are dished where the direct injector protrudes into the combustion chamber... so that it creates a swirl pot and can use just a tiny squirt of fuel there and then ignite it, rather than igniting a whole chamber of fuel which is what you always have to do in a port-injected engine 🤔

[@jordanlatta]

I guess this means that cars with this D4-S system like highway driving more than city, so that more time is spent cleaning the valves with port injection

[@christopherdimotsis1024]

@@jordanlatta the while yes GDI helps also with getting a leaner mixture the ideal range is stoic which is just enough air to burn the amount of fuel you inject because if you start going lean you can produce NOx (Nitrates of Oxides) which is a whole other gas that is also harmful and is produced by Diesel engines due to how they operate very lean mixtures and with compression ignition, not spark ignition like a gasoline engine. This also is why the after treatment system on diesels are bigger and more expensive….If you look into the newer Dynamic Force engine Toyota makes they came up with combining the D4S injection system with a longer and straighter intake runner to improve fuel mixing at low rpm with the “tumble effect” and becomes amplified at higher rpms to mix the air and fuel more evenly so that they can achieve leaner combustion and make more power and be more efficient when you want to be.

[@stevevarney7064]

Just wanted to say thank you I have a 2011 Subaru outback 3.6 r and just from your videos I fixed my car tore all the chains down and put everything back in time

[@1atinlove]

Awesome class professor. Keep the FA series coming.

[@golding69]

Feel very thankful for MrSubaru's informative videos. I knew nothing of Subaru's (and very little about cars' tech and mechanical) until I recently got hooked and very curious, from buying a 2020 BRZ tS, which lead me to buy a used 2018 Impreza limited. Now I look at car videos everyday! It's become an obsession and I'm extremely thankful for your informative videos!

[@wtdonovan]

Thanks for making this knowledge and detail available in an expertly presented video!

[@hedbngr18]

I have this in my 2016 Tacoma 3.5L. I was super leary about buying a new drivetrain in its first year, but I've been happy with it so far. 70,000 miles with no issues. Haven't had any reason to crack into the engine, but it runs like the day I bought it. I now have a company vehicle, so the Taco only moves 3-4000 miles a year these days.

[@bobmcl2406]

Thanks for this good clear explanation. Personally, I think we were at the apex of practical engine technology with port injection. GDI provides only incremental improvement, with a ton of downside. Having to do a major service at 30k miles is a massive step back. This hybrid system does solve that carbon build-up issue, but it adds much complexity. Just my opinion, YMMV (especially true in this discussion, I suppose 😁 ).

[@bigdaddymak1439]

You can reduce the deposits by a lot by making sure you get you engine up to operating temperature enough to burn of impurities and condensation that builds up. They're coming out with induction cleaning products to service the valves at an interval through the intake tube. I believe BG has one

[@jameshyde1501]

I have always been told to “Keep it simple” perhaps this system will prove to be simple indeed! Technology always delves into TOO!... much complexity, thus adding to the cost of repairs.

[@angry_ike7628]

Kind of glad I got a last-gasp production 2019 BN Legacy with the port-injected FB25B. Would take a Legacy XT with the turbo FA24F if they ever figure out a dual injection system or get to use the D-4S system.

[@davidd166]

Fantastic as always

[@clarencehoover6748]

Excellent. Thanks for sharing! This makes me appreciate my treasured EJ “dinosaur” engine a bit more.

[@XfStef]

Excellent information. I'll ask my dealership about doing this valve cleanup in the near future.

[@OggaDugga]

My Tacoma has the exact same fuel setup. It’s great tbh.

[@kevinm5177]

Great visual tour, thanks!

[@doctorrobert60]

Interesting and educational video. Thank you for posting it for us!

[@Mrunal4Tech]

Love the detailed video, Appreciate it as always!

[@orbitalgolem91]

My understanding is that the hybrid port/direct system is patented by Toyota, and who can blame them as significant R&D costs involved, and manufacturers can license it for use.

[@joshlopez9056]

I believe ford has a similar system with the 5.0 coyote engine

[@davesmith3884]

Ford Ranger 2.3 in their 2019-2021 American version is Direct fuel injection along with turbo charge. That has to be a interesting engine to work on. There are a lot of complaints that the oil is diluted with gas in local city driving. Long distance driving no to many complaints with oil diluted with gas.

[@courtneyblackwell9211]

great video....interesting the pressure required for DIT system

[@MegaGeorge1948]

My understanding of the Toyota duel injector system is that the port injectors work in low power demands and the direct injectors work when more power is needed. So if the driver is stingy on the gas pedal, his intake valves would remain cleaner longer.

[@cappierising1774]

you should change your youtube channel name to ProfSubaru1387. "Professor" You earned it !!

[@mr.nobody4900]

Two Thumbs Up

[@steveoSW80]

Those injectors (high pressure direct)suck ass! Like wrestling a mama black bear! It came back after the valve recall burnt to the ground. Stay safe! Great video! See you at Toyota woven city !?!

[@lp2565]

Great run down! Thanks for sharing!

[@jp2246]

Wow, this was well done, thanks!

[@kevinW826]

Awesome explanation Mr Subaru. Questions, in one of your older videos you briefly mentioned the Subaru Tribeca has unique ball joints vs the Outback/Legacy/Accent. I am looking at a 2013 Tribeca with 130,000 kms. Before I go look at it, how rare or hard is it to source those ball joints if I need to replace them? Also how reliable were they in general? There is not a lot of information that I have found regarding the Tribeca.

[@garybergfield8283]

Mr S, Very nice and informative. BUT!! For us guys with the DI engines, can you recommend installing an oil catch can or a good procedure for addressing the buildup on the valves? I am a DIY guy and can do most anything. Is the Subaru process of sucking the cleaner into the intake manifold really effective? Or, do I remove the intake manifold and try to clean the valves from there and with the valves closed suck out all the crap that I get loose? How about giving us a video on options and procedures for addressing this issue, based on your experiences? Thank you

[@MrSubaru1387]

More DI vids to follow.

[@shaunrutherford7764]

Any chance you could do a video on proper maintenance on fb25di to reduce headaches later on? I'm debating whether to trust Subaru's oil and going to one specifically designed for di engines plus Purolator filters and cvc treatment. Good idea or no?

[@JasPlun]

D4S has been great on my wife's 2020 Camry SE. They are reliable, but can have on rare occasions leaks form around the Direct Injectors which is common on other brands and rare on Toyotas. It is still the best salution to the carbon build up issues. Ford is now implementing their version of D4S on some of their Eco-Boost engines and it has also reduced carbon. I have never owned a Subaru, but I have been interested in doing so at some point. I have always held back because I was told they for awhile had a lot of Head Gasket failures. Have they found a way to reduce the failure rates with the newer Subaru engines? Another thing that kept me from buying Subaru is the use of CVT transmissions.

[@dougrodriguez4977]

Another great video, thank you.

[@dominicancheif117]

Very educational, thanks 👍

[@muhammedakyuz9126]

Can you make a video about "air blowing out of oil cap?" ? How much pressure should be coming out of the oil cap?

[@Spawn223311]

Thanks for the video 🖖🏻

[@ThatManitobaGuy]

D4-S is such a great system Ford has copied it to fix their Direct Injection issues.

[@shawnconary6810]

What’s the DIY replace-ability for the DI and port fuel pumps? Doesn’t seem like too much needs to be moved out of the way from what i can tell. Im eyeballing the new BRZ and wondering how feasible this is for me if i ever need to handle it. Thanks for all the content, sir. Unbelievably informative.

[@jamesbruno5896]

Nice job!

[@chrisb9478]

I think Hyundai is offering it now on some engine? I have a 21 Tacoma with it. I hope our 21 Outback XT doesn’t run into problems with higher mileage.

[@valdius85]

Even some VAGs come with it now. :)

[@comickebs748]

FINALLY. Now can they stuff it into the Forester AND return to using the hydraulic handbrake????

[@dmitripetrov5536]

Oil catch can is the only solution to this problem. It will not eliminate carbon deposits completely but can prevent from worse cases happening.

[@jasonrolison6997]

Can you do a video on installing an oil catch can on a newer Subaru 2.0. I just bought a 2020 Crosstrek and want to try prevent as much valve coking as possible.

[@rrowe3774]

I have the FB20D in a 2019 Impreza (fun car). From your experience, what is the process to clean the intake valves? And how often should it be done?

[@MrSubaru1387]

Check my latest upload. kzbin.info/www/bejne/amPMo62agLCZrZo

[@b18craz]

MrSubaru Please do a video explaining Subaru Direct Injection. Why are there only 3 lobes on the camshaft driving the hp fuel pump? Is it a returnless system?

[@Nora-tp7dp]

Ugh, this is the reason why I’m on the fence about buying a crosstrek! Is it that bad carbon buildup? I’m no mechanic and this seems like a pain.

[@valdius85]

Please make more videos on how to limit the carbon buildup on NA engines. I've got an e-boxer Forester 2021. Is catch can a good idea? Will it brake my warranty?

[@MrSubaru1387]

Catch can can help, AOS (air oil separator) is better. Yes, as far as I've heard, it'll void power train warranty.

[@bigdaddymak1439]

The majority of people with valves carboning up are short trip drivers. The impurities in the oil the build up never get burned off and the get into the pcv system. Make sure you take enough long drives and it will reduce these deposits.

[@bigdaddymak1439]

You can reduce the deposits by a lot by making sure you get you engine up to operating temperature enough to burn of impurities and condensation that builds up. They're coming out with induction cleaning products to service the valves at an interval through the intake tube.

[@valdius85]

@@bigdaddymak1439 Thank you. I'd say around 70% of the milage is motorway/rural roads for over 1h at the time.

[@ValentinArzola]

The Lexus 3.5L V6 also has both port and direct injection fuel systems.

[@MrSubaru1387]

Yes, Toyota is rolling it out across their product lines.

[@55whiplash]

Almost all new non-hybrids have this direct injection. I think the new Honda 2.0 liter doesn't have it in the HR-V, and the engine isn't particularly powerful. But I've heard enough about this high pressure system to consider it anyway.

[@Mabeylater293]

Toyota is what happens when reliability is a PRIORITY.

[@pilot1226]

So what’s the takeaway for my FA24? Should I pay my dealer to do the “optional” throttle body service every 30k, or is there something I should specifically ask for?

[@brybit]

Is it true that I can simply install an air-oil separator or “catch can” to solve most all of this buildup problem? I have not done it, but I have certainly seen them for sale from highly reputable suppliers.

[@jbradley920rox]

For turbos its a pretty regular thing. I have 2 on my turbo subi. But the pcv is deleted. For non turbos it's a little pointless. I've put one on just to see and I don't really collect much, but I also don't have any gas getting mixed into my oil as much. I can smell the vapor in the can. Also I guess it's good because if my pcv fails again I'll know pretty quickly without having that mysterious oil consumption just to find it in my tailpipe. Nevertheless

[@seandvideo]

I just bought a 2021 Crosstrek with GDI. Any suggestions on how to prevent these carbon issues?

[@medicfour9268]

To the best of my knowledge you have to put a vaporized solvent in thru the intake system every 20k-30k miles. or take it apart and scrape it out with wooden/plastic tools and solvent cleaner that softens the goop up. No personal experience on this but TsTseminars has a few videos on YT that show it and the amount of build up of the 20k-30k vaporized intake cleaning is not performed

[@fredharvey2720]

I'll take an outback xt with this new system. 😃

[@quinnsteeves295]

Dual injection is coming on a lot of engines in the next few years

[@kimlground206]

Of course it is. It is more expensive, more complicated, and less repairable just to deliver a pretty miniscule fuel economy improvement over direct port injection. What else would you expect from any auto maker ?

[@krispyywombat7382]

@@kimlground206 Do you like having to walnut blast your valves every 20-80k miles on a DI car? DI offers tons of benefits to the drivability and performance of modern cars but it's not without its flaws, and whacking on a few extra injectors in the intake manifold is a pretty good solution to those flaws.

[@louisminnaar8418]

Have we seen real serious issues with Di on the newer Subaru engines? Surely it should have occurred by now since 2017.

[@TexasHarleyBoy65]

My 2018 F150 2.7 ecoboost has this same system.

[@timbrown9731]

So for light throttle apps I'm assuming that Toyota is only using multi port and under heavy load max throttle DI kicks over?

[@MrSubaru1387]

Idle, and lower rpm, DI and PI are used. At higher rpm/engine speeds, it switches to DI only.

[@zaceryhammond1144]

@@MrSubaru1387 so that would explain the weird sound I’m hearing when I do a pull and there’s high load on the engine it sounded like something to do with the fuel system but this is reassuring

[@michaelbrennan7148]

Thank you.

[@bradq2769]

I have a '18 Impreza with 37k miles. How much is that service? I haven't noticed a decrease in performance yet.

[@jasonotto650]

We're the older forester port injection ? When did they introduce direct injection?

[@kidwelldavid6136]

Can sea foam be used to clean up the carbon? Or some kind of injector cleaner.

[@MrSubaru1387]

Injector cleaner doesn't do anything for the valves in a DI only system.

[@kimlground206]

@@MrSubaru1387 It is true that these solvents never see the valves in a DI system when the stuff is put into the fuel. But there is no reason one can't make a fuel / solvent mixture and spray it into the intake while the engine is running. There almost certainly is a suitably diluted aerosol product intended for just this sort of application. I remember a decarbonizer and fuel system cleaner from the 1960s that you just poured into the carburetor while the engine was running. Don't recall the name.

[@MrSubaru1387]

Nothing put in the fuel tank, will touch the valves on a straight DI system. Total waste of time and money.

[@frizzen]

@@kimlground206 Sea Foam. I was wondering if that would help clean the valves too.

[@kimlground206]

@@frizzen I've never used it. I think of Sea Foam as a fuel treatment similar to that red stuff that I can't recall the name of right now to prevent ethanol separation and damage. For cleaning I recommend Lucas fuel system / injector cleaner (I run some through each of my vehicles -none of which have direct injection - a couple of times a year by adding to fuel.) For a direct injection engine I would dilute about half and half with gas and then spray into the intake while the engine is running, not so much it chokes out the engine. I've never tried this, but would definitely try it as a periodic treatment if I had a DI car. I am confident the treatment will not harm engine or sensors, but what is my word worth?

[@networth9151]

If I have a 2014 RAV4 with a 2.5L engine how do I determine if it has the D-4S fuel injection system?

[@GO-zg7ox]

Thanks!

[@larrycisneros929]

I get what’s going on here... D-4s... better than we have been doing things. Wouldn’t it make more seance to have crankcase ventilation/recovery system after internal combustion? I’m not an engineer, just a tech, worried that expensive walnut shell jobs are costing us customers, trust.

[@weeekwo3245]

i was just thinking about this and here you done gone made a video. so is the d4s fuel injection how it makes 202 hp whereas the fb20 imprezas make 148 ponies? what is the advantage over just upgrading the port injectors? thoughts? omg thanks!

[@MrSubaru1387]

No, bore and stroke are different, different heads/cams, etc. The only thing similar between the FA20 and FB20 is the fact that they're F series engines, that are 2.0L in displacement

[@weeekwo3245]

@@MrSubaru1387 i mean it is barely different given bore is 86 vs 84mm, and stroke 86 vs 90mm (cf. wiki); so then the differences betweens heads and cams amount to geometry. 4mm is less than 5% of travel for more efficient rpms, but the engine output is still 33% greater. so that leaves 28% of power gain to the injectors with the rom tune. thoughts? omg thanks!

[@snackyxchan]

Can you elaborate on oil catch cans and induction services i.e MOC or BG for direct Injection non d4s engines?

[@lawrencecavens5760]

Being that Ford also used the same system Someone came out with catch a can system to help control the PCV vapours. Would this help in this instance ??

[@GO-zg7ox]

Ok I need your advice! My honey will kill me since I talked her into the 21 crosstrek. I want that AOS to avoid the issues in the future. Which brand do you recomend? I saw the Crawford and its looks easy to install. But another one had coolant going to it...So just waiting on your advice. Gets me mad just thinking about how the valves looked in that picture...Great job as always!

[@MrSubaru1387]

Issue is, I've heard Subaru dealers will void your power train warranty if you install one.

[@GO-zg7ox]

@@MrSubaru1387 Ok lets say after the warranty is over lol. Which would you pick? :)

[@MrSubaru1387]

@@GO-zg7ox I honestly don't have any opinions on them as I have no experience with installing or results from any of them.

[@GO-zg7ox]

@@MrSubaru1387 Oh ok! I missunderstood. I was thinking it would help with the carbon buildup. Sorry to bother you.

[@MrSubaru1387]

No, you're good. I just can't recommend one over another because I don't have any experience/data on them. Been running them for a long time on turbo cars, not sure the effectiveness on the N/As.

[@Jordan__Sloan]

Mmmm hmm love me some subarus

[@shvak2063]

Im nearing my 30k on my 19 trek, will my dealership be able to do some carbon cleaning?

[@norm1815]

Now if they can just fix the RTV coming loose in the oil pan and clogging up the oil pickup on the new 2022 Gr86 and BRZ .......

[@kimlground206]

And for those with the direct system . . . Why not a periodic dose of that decarbonizer / fuel system cleaner that you spray into the intake while the engine is running ? That carbon build up is really ugly.

[@WholeCosmos]

can I put this on my 2017 forester XT?

[@EngineersHomestead]

2k psi...those are rookie numbers in this racket. *laughs in diesel* But seriously, fluid injection injuries are no joke and will ruin your day and/or hands and arms.

[@jeromegaces6184]

So you can swap out the stock intake manifold of FA20F for the intake manifold of FA20D with port injection? or is there other things that needs to be changed before you can put the D-4S to your forester or crosstrek?

[@MrSubaru1387]

No. If only it were that simple.

[@larrygibbons6489]

I need advice. Spun Bearing on my FRS, so I purchased a new short block from Toyota. Sending my heads to machine shop for renewing. Will I need to adjust valve tolerance with new shims or just leave the original shims in place? Thank You

[@MrSubaru1387]

I'd have the machine shop handle it all and not worry about it.

[@larrygibbons6489]

@@MrSubaru1387 thank You

[@AA-mk4pu]

Do you recommend a oil catch can on fa24 turbo?

[@SHARP1991]

Would Port injection alone still make an engine run cleaner then d4-s?

[@MrSubaru1387]

It's pretty neck and neck. The DI injectors work solo only at higher rpm. Not really enough to matter, cause significant build-up.

[@SHARP1991]

@@MrSubaru1387 Oh nice, great information and appreciate you taking the time to respond. Hope you have a good week!

[@anthonyvitori1299]

the only agreement toyota needs with subaru is actually install a toyota engine in the 86...I'm sure Toyota would sell twice as many as it sells now

[@timothye5936]

SCIENCE!!!…

[@jamesthorp9271]

Do you know if anybody has done a conversion to put this system on one of the FA20DIT setups?

[@MrSubaru1387]

Not that I'm aware of, no.

[@hphillips7425]

If Subaru used this system on all their vehicles I would have purchased another forester wilderness instead of a RAV4

[@charger19691]

Change your oil at 3,000 miles with synthetic oil. It will help keep the carbon buildup off the valves in direct injection engines.

[@MrSubaru1387]

No, it won't. It'll still build up.

[@charger19691]

@@MrSubaru1387 , I respectfully disagree. Driving long extended oil drain intervals in GDI engines is a recipe for disaster.

[@MrSubaru1387]

@@charger19691 you can disagree all you like, carbon will still form on the intake valves.

[@charger19691]

@@MrSubaru1387 , Whatever.

[@pcmountaindog]

Direct injection, what bad idea. I will be keeping my port injector car. I will not even consider any car with only direct injection. This is just plain stupid.

[@Peexaa69]

Great video mr. Subaru! I wanted to ask, what your thoughts on alternative services for servicing intake valve cleaning are ie CRC GDI intake valve & turbo cleaner are (as opposed to manually cleaning it via walnut blasting). Thanks so much in advance!