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2019 Forester Sport CVT
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OK, this thread is about the 2019 direct injection 2.5.

Quality fuel additives are naphtha and PEA, not alcohol. Even the direct injectors need a bit of cleaning, if you aren't using a Top Tier gasoline with every refill. A bottle of the Techron concentrate every 5,000 miles is probably sufficient.

To limit pre-ignition risk, low speed or hard acceleration, I add RXP every 5 refills, or so. A proven carbon cleaner.

As for cleaning the valve stems, that is indeed an important issue for this engine. If the Subaru service, really adds a cleaning solution to the intake, which dissolves any accumulated crud, that is smart. Something I will ask the dealer about at 30,000 miles.
 

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2018 FXT-T CVT / 2014 VW Passat TDI SEL
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I'm coming from the GM and specially we were told by the GM Performance team that running fuel injector cleaners was not helpful on the 2,000+PSI systems.
That is sure interesting when it's considered required maintenance by some OEMs on DI engines. And I still have no idea what pressure has to do with it. Buildup around the injector nozzle causing a flow problem is, in fact, making contact with the fuel and it would be considered constant contact while that injector is operating with the blockage.

For the reasons I stated above. Contact time and raising alcohol levels long term.
Please explain the alcohol levels comment....10% of our fuel is already alcohol and we've got fuel systems resistant to it....so how much higher are we worried about a little bottle of cleaner increasing those levels every...what 15 tanks of fuel? And PEA isn't even alcohol. I understand some that aren't using PEA may have alcohol as a solvent...but at what concentrations?

My understanding was that your post was about removing the injectors and having them cleaned, verse the Topic of running cleaners in the system at various maintenance intervals. Which is what I thought this thread was about.
I can only conclude if that was your belief, you misread, or entirely missed my first post.

Again, fuel injector cleaners typically do nothing in DI systems.

Higher detergent gasoline is a better way to clean the system. Not paying the dealer hundreds to drop snake juice in the tank.
You know....you can both use good fuel AND supplement with fuel injector cleaner without harm. I promise. You also don't need to pay more than a bottle costs at your local auto parts store. Just might help keep a flow problem from forming.
 

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1. The pressure itself keeps the main portion of the injector clear during most operation.
2. The issue the GM engines had was that as alcohol content rose, the chance of the injector seal deteriorating was high. Hopefully Subaru put in seals that are fully compatible with higher alcohol levels.
3. I wonder how much of the build up is due to an incomplete burn/****ty gas.


But it goes back to, does dumping a $10 bottle of Chevron with Techron in yearly do as much as running Chevron high detergent gasoline year round?
 

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Sahuarita, Arizona USA 2018 Forester Limited
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Do you have Texaco stations on the east coast? If so Texaco gasoline now contains Techron. Texaco is a subsidiary of Chevron.
 

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2017 Outback Premium 2020 Forester Limited
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In a previous life I had a 2012 GMC Terrain that had direct injection. The owners manual recommended using "Top Tier" gas (https://www.toptiergas.com/licensed-brands). I always did and used BP, Shell, Exxon or Citgo. It supposedly has extra additives to help keep the valves clean and really doesn't cost any more than non Top Tier. In addition to that I dumped in a bottle of Techron at every oil change. I never needed the dealer ridiculous $170 upcharge.
 

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Direct injection might need a walnut blasting. TheShopCT in Stratford does the service. Tell’em Adrian with the forester sent ya.
The walnut blasting does not actually clean the fuel injection system, it removes deposits from the intake valves, and is probably unnecessary at 13,000 miles.
 

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2020 Forester Sport
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The walnut blasting does not actually clean the fuel injection system, it removes deposits from the intake valves, and is probably unnecessary at 13,000 miles.
It all depends on the driving behavior. If the car is being driven with short trips and never gets up to operating temps, those carbon deposits get caked up quick.

I had a 16 wrx with the same DIT engine. At 40k it was bad to the point of causing misfiring, low compression in one cylinder, etc.


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