Direct Inject Cleaning solutions

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  • Matt
    Senior Member
    • Dec 2008
    • 328

    Direct Inject Cleaning solutions

    Any suggestions on direct injection cleaners? Some are part of a induction system that force the solution into the intake and some you just pour in the fuel tank. Any success stories? Fails?
    Last edited by Matt; 03-07-2019, 04:59 PM.
  • BRIAN617
    Senior Member
    • Dec 2016
    • 153

    #2
    Originally posted by Matt
    and some you just poor in the fuel tank
    Just throwing this out there,

    The inherent problem with DI is the fact that the fuel isn't injected onto the back of the valves causing the carbon build up.

    So if you think about it, nothing you'd pour in the tank could possibly work.

    Comment

    • Glide
      Senior Member
      • Jan 2015
      • 303

      #3
      Originally posted by BRIAN617
      So if you think about it, nothing you'd pour in the tank could possibly work.
      I'll post a question.Where do you think the carbon comes from?
      And I'll answer it.With todays camshaft designs there is a lot of overlap which causes reversion into the intake manifold (sometimes now called a "surge tank").The carbon is a product of the combustion gases that revert into the intake.
      General Motors,Hyundai,Kia and some others recommend as maintenance adding a bottle of their branded fuel system or fuel injector cleaner at each oil change.Following this will prevent carbon buildup on intake valves as the cleaner is carried to the intake valves with the combustion gases.It does work.
      BMW recommends walnut shell blasting of the intake valves as maintenance .

      Comment

      • BRIAN617
        Senior Member
        • Dec 2016
        • 153

        #4
        But do you think that tiny amount of reversion from cam overlap has more to do with deposits than the PCV system?

        Generally speaking most OEM cam designs have little if no overlap and with VVT I would suspect even less overlap, even with more aggressive lobe design.

        Maybe I used "carbon deposits" loosely

        Comment

        • Matt
          Senior Member
          • Dec 2008
          • 328

          #5
          I'm seeing some GM 3.6L, 125,000+ miles, coming in with P0300s. Spark plugs and coils are good so I'm just wondering about misfires at idle due to this carbon build up.

          Comment

          • Glide
            Senior Member
            • Jan 2015
            • 303

            #6
            Anything published by the OEMs that I have read blames the carbon buildup entirely on reversion and the fuel system and injector cleaners do work to keep the intake valves clean,which would seem to prove that.

            Comment

            • Crusty
              Senior Member
              • Dec 2007
              • 2450

              #7
              Valve guides.
              They all have some lubrication (they CAN'T run DRY) and over time it builds up.
              It used to be cleaned using better grades of fuel with TBI and PORT injection systems but the GDI doesn't allow cleaners in fuels to get to the intake valves where the vacuum (low pressure) tends to pull what lubrication is there down the guides.

              Comment

              • Glide
                Senior Member
                • Jan 2015
                • 303

                #8
                Originally posted by Matt
                I'm seeing some GM 3.6L, 125,000+ miles, coming in with P0300s. Spark plugs and coils are good so I'm just wondering about misfires at idle due to this carbon build up.
                Could very well be.There is also a calibration update for P0300,at least on Acadia.Just did one after cleaning carbon deposits with GM upper cylinder cleaner and replacing spark plugs(which were badly carboned).

                Comment

                • BRIAN617
                  Senior Member
                  • Dec 2016
                  • 153

                  #9
                  That's interesting. Sure doesnt make sense to me when you compare 150k mile engines direct vs conventional.

                  Read somewhere the other day one of the OEMs is adding port injection to a direct injected engine to help keep the valves clean. I'll try to find that article.

                  Comment

                  • Glide
                    Senior Member
                    • Jan 2015
                    • 303

                    #10
                    Originally posted by BRIAN617
                    That's interesting. Sure doesnt make sense to me when you compare 150k mile engines direct vs conventional.
                    .
                    Your first statement which was correct explains it.The fuel spray from port injectors does help keep the intake valves clean.
                    The OEMs will have to do something to correct this issue with direct injection.As we all know,expecting customers to follow their maintenance Schedule is wishful thinking.
                    Attached Files

                    Comment

                    • Joe Rappa
                      Snap-on DSD
                      • Aug 2007
                      • 2050

                      #11
                      If you're looking for opinions, I've got one. I've never seen any type of Foo Foo Juice work to clean valves on a DI car. I've seen lots of claims, but if you take a before/after shot with a bore scope I've found little-no difference.
                      The only thing I've seen work perfectly so far is walnut shell blasting. It's a lot more work than running a cleaner through the engine, but at least you'll have something to show for your efforts.

                      Joe
                      "You don't build a reputation on what you're going to do"
                      Henry Ford

                      Comment

                      • BRIAN617
                        Senior Member
                        • Dec 2016
                        • 153

                        #12
                        Originally posted by Joe Rappa
                        If you're looking for opinions, I've got one. I've never seen any type of Foo Foo Juice work to clean valves on a DI car. I've seen lots of claims, but if you take a before/after shot with a bore scope I've found little-no difference.
                        The only thing I've seen work perfectly so far is walnut shell blasting. It's a lot more work than running a cleaner through the engine, but at least you'll have something to show for your efforts.

                        Joe
                        And just think of all those walnuts you get to eat so you can use the shells.

                        WIN WIN

                        Comment

                        • Joe Rappa
                          Snap-on DSD
                          • Aug 2007
                          • 2050

                          #13
                          Originally posted by BRIAN617
                          And just think of all those walnuts you get to eat so you can use the shells.

                          WIN WIN


                          I have an unfair advantage on that. I just shake them out of my head! they come right out my ears.
                          "You don't build a reputation on what you're going to do"
                          Henry Ford

                          Comment

                          • Glide
                            Senior Member
                            • Jan 2015
                            • 303

                            #14
                            Originally posted by Joe Rappa
                            If you're looking for opinions, I've got one. I've never seen any type of Foo Foo Juice work to clean valves on a DI car. I've seen lots of claims, but if you take a before/after shot with a bore scope I've found little-no difference.
                            The only thing I've seen work perfectly so far is walnut shell blasting. It's a lot more work than running a cleaner through the engine, but at least you'll have something to show for your efforts.

                            Joe
                            If you are talking about cleaning the valves after the customer doesn't do their maintenance and they are severely carboned,walnut shell blasting does work best,not perfectly,as some engines don't allow for good access to the valves through the intake ports .GM top engine cleaner poured directly
                            on the valves and let sit will soften the carbon so it can be wiped off.
                            One Hytac operator suggested that I use oven cleaner,it didn't work as well as the GM stuff.

                            Comment

                            • Witsend
                              Banned
                              • Nov 2012
                              • 2942

                              #15
                              I think most that carbon build up comes from blow by and the oil vapor pulled through the crankcase ventilation system , especially with turbo charging where the amount of oil misting that cokes on the back of hot valves can be reduced with a catch can system if drained regularly

                              Comment

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