Username or Email Address
Do you already have an account?
Forgot your password?
  • Log in or Sign up

    VWVortex


    The Car Lounge
    Page 2 of 2 FirstFirst 12
    Results 26 to 47 of 47

    Thread: Direct injection causes intake valve buildup?

    1. Member abawp's Avatar
      Join Date
      Nov 30th, 2005
      Location
      VA Beach
      Posts
      12,299
      Vehicles
      2002 Subaru Outback, 2003 Miata, 2006 EX500R, 2011 ZX-6R
      05-19-2009 06:06 PM #26
      Quote, originally posted by Bull0080 »
      Use TOP TIER Detergent Gasoline every few tanks. At least that is what my Audi dealer told me, he actually said i would rather see you using a LESS octane top Tier fuel than a higher non Top Tier octane. They even game me a flyer explaining why and what stations pump Top Tier fuel

      Care to explain this with regards to a direct injection motor? The logic doesn't seem to be there from the dealership
      Quote Originally Posted by Lwize View Post
      What, none of you watch reruns on TV?
      Quote Originally Posted by NPH View Post
      I don't know about you but, I get angry and shout "IB4TL" when one comes on.

    2. Member adrew's Avatar
      Join Date
      Aug 14th, 2003
      Location
      Texas
      Posts
      13,692
      Vehicles
      '12 Yaris, '14 Mirage, 2.7 liters total
      05-19-2009 06:13 PM #27
      So the consensus is that stuff from the EGR and PCV is gunking up on the valves?
      Where do these dump in on the DI engines? Is the intake manifold/runners getting gunked up, too?
      Ooh, I'd be pissed if I dropped megabucks on an RS4. My cars get frequent Italian tuneups and are always shiny and clean inside.
      Improving the signal-to-noise ratio

    3. Member PhReE's Avatar
      Join Date
      Sep 16th, 2004
      Location
      Taylorsville, UT
      Posts
      9,040
      Vehicles
      2004 Turbo VR6
      05-19-2009 06:13 PM #28
      All the gas is the same -- only the detergents (slightly) differ...
      -James
      04 GTI Silverstone 24vT :: GT35r - TT 264/260 - Unitronic 630cc - Bosch 044 - Area51 SRI - Full 3" TB :: More in progress
      >> http://zingledot.myminicity.com/ | http://sourceforge.net/projects/imagizer2 <<

    4. Member greatfox's Avatar
      Join Date
      Mar 5th, 2005
      Location
      SoCal
      Posts
      8,056
      Vehicles
      '00 Boxster Wannabe
      05-19-2009 06:16 PM #29
      Quote, originally posted by Bull0080 &raquo;
      Use TOP TIER Detergent Gasoline every few tanks. At least that is what my Audi dealer told me, he actually said i would rather see you using a LESS octane top Tier fuel than a higher non Top Tier octane. They even game me a flyer explaining why and what stations pump Top Tier fuel

      DI engines inject fuel into the cylinder, not into the intake port, so the intake valve buildup would be unaffected by gasoline grade. That said, I wouldn't suggest buying 87 octane at ARCO
      Quote Originally Posted by iamnotemo View Post
      ...I am jealous of your shift knob. That is a shape I love.
      Quote Originally Posted by elementpb View Post
      your mom sounds like my kind of lady. is she single and/or discrete?

    5. Member
      Join Date
      Jan 6th, 2004
      Location
      Ft. Lauderdale, Florida
      Posts
      1,096
      Vehicles
      '02 337, '06 CBR600RR
      05-19-2009 06:19 PM #30
      We just got the new Jag 5.0 L V8 with direct injections. We'll see how it plays out, usually jag is on top of stuff like this.

    6. Member PhReE's Avatar
      Join Date
      Sep 16th, 2004
      Location
      Taylorsville, UT
      Posts
      9,040
      Vehicles
      2004 Turbo VR6
      05-19-2009 06:22 PM #31
      The problem is emissions. You have to re-route the crank case vent to the intake to pass emissions, and that is exactly what causes the problem.
      -James
      04 GTI Silverstone 24vT :: GT35r - TT 264/260 - Unitronic 630cc - Bosch 044 - Area51 SRI - Full 3" TB :: More in progress
      >> http://zingledot.myminicity.com/ | http://sourceforge.net/projects/imagizer2 <<

    7. Member
      Join Date
      May 18th, 2002
      Location
      Tampa, FL
      Posts
      929
      Vehicles
      04 Shedding TR R32
      05-19-2009 06:31 PM #32
      time for this
      Quote Originally Posted by PowerDubs View Post
      You can't see your engine bay while you drive, and popping your hood in a parking lot to show off parts is as stupid as listing them in your signature.. (not what the parts were intended for).
      WiTW '10 WiTW '11 WiTW '12

    8. Member greatfox's Avatar
      Join Date
      Mar 5th, 2005
      Location
      SoCal
      Posts
      8,056
      Vehicles
      '00 Boxster Wannabe
      05-19-2009 06:38 PM #33
      Quote, originally posted by shinnersvr6 &raquo;
      time for this

      do I have to quote myself?
      Quote, originally posted by greatfox &raquo;
      DI engines inject fuel into the cylinder, not into the intake port, so the intake valve buildup would be unaffected by gasoline grade. That said, I wouldn't suggest buying 87 octane at ARCO

      and yes that goes for the gimicky "Nitrogen Enriched" Shell gas
      Quote Originally Posted by iamnotemo View Post
      ...I am jealous of your shift knob. That is a shape I love.
      Quote Originally Posted by elementpb View Post
      your mom sounds like my kind of lady. is she single and/or discrete?

    9. Member abawp's Avatar
      Join Date
      Nov 30th, 2005
      Location
      VA Beach
      Posts
      12,299
      Vehicles
      2002 Subaru Outback, 2003 Miata, 2006 EX500R, 2011 ZX-6R
      05-19-2009 06:43 PM #34
      Quote, originally posted by PhReE &raquo;
      The problem is emissions. You have to re-route the crank case vent to the intake to pass emissions, and that is exactly what causes the problem.

      Isn't the emissions reason to keep fumes from escaping into the atmosphere? I don't think it would affect emissions negatively if the fumes were routed into the exhaust and an air pump were supplemented to help burn off the fumes.
      Quote Originally Posted by Lwize View Post
      What, none of you watch reruns on TV?
      Quote Originally Posted by NPH View Post
      I don't know about you but, I get angry and shout "IB4TL" when one comes on.

    10. Member Shomegrown's Avatar
      Join Date
      Feb 26th, 2002
      Location
      Detroit
      Posts
      18,890
      Vehicles
      Current: Audi S4, Q5 TDI quattro, Porsche Boxster S, Ford F-150 FX4 4x4
      05-19-2009 06:46 PM #35
      Um guys...
      Cam overlap EGR means combution deposits (and unburned fuel) still end up on the valves. Gasoline does matter.

    11. Member greatfox's Avatar
      Join Date
      Mar 5th, 2005
      Location
      SoCal
      Posts
      8,056
      Vehicles
      '00 Boxster Wannabe
      05-19-2009 07:01 PM #36
      Quote, originally posted by Shomegrown &raquo;
      Um guys...
      Cam overlap EGR means combution deposits (and unburned fuel) still end up on the valves. Gasoline does matter.

      DI engines inject the gasoline very late in the compression stage. There is no way gas is going backwards into the intake.
      Quote Originally Posted by iamnotemo View Post
      ...I am jealous of your shift knob. That is a shape I love.
      Quote Originally Posted by elementpb View Post
      your mom sounds like my kind of lady. is she single and/or discrete?

    12. Member Shomegrown's Avatar
      Join Date
      Feb 26th, 2002
      Location
      Detroit
      Posts
      18,890
      Vehicles
      Current: Audi S4, Q5 TDI quattro, Porsche Boxster S, Ford F-150 FX4 4x4
      05-19-2009 08:42 PM #37
      Quote, originally posted by greatfox &raquo;
      DI engines inject the gasoline very late in the compression stage. There is no way gas is going backwards into the intake.

      I guess I assumed some here could figure out how internal EGR works.
      Basically during the exhaust stroke, the intake valves are opened early before the exhaust is finished exiting the combustion chamber. This forces dirty exhaust, oil, and unburned gasoline hydrocarbons back up into the intake valves and intake ports.
      It has nothing to do with when fuel is injected into the combustion chamber because EGR function occurs later during the end of the exhaust stroke.
      *edit* - To clarify your other point, the injection event doesn't take place late on gasoline engines. You might be confusing things with diesels which inject after the intake valves are closed and during compression.
      On gasoline direct injection engines, you are spraying while the valves are open which means some spray ends up on the valves. Watch the video.
      http://www.youtube.com/watch?v=qd90yHlmfS4
      http://www.youtube.com/watch?v=73BrXCsbd64




      Modified by Shomegrown at 1:49 AM 5-20-2009

    13. Geriatric Member ByronLLN's Avatar
      Join Date
      Jul 29th, 2004
      Location
      Annapolis, MD
      Posts
      38,403
      Vehicles
      '15 5.0, '13 Focus, '97 Wrangler, '90 Miata
      05-19-2009 09:03 PM #38
      DISI owners have been addressing this by running an oil catch can with redundant in-line PCV valves along with water or meth injection. It seems to help reduce the build-up in the intake manifold and on the valves, but only time will tell how effective it is.
      www.leftlanenews.com
      @SSLByron, @leftlanenews
      Domestic Muscle Owners Not-So-Anonymous
      Quote Originally Posted by atomicalex View Post
      Can we just have more boob pics, please?

    14. Member greatfox's Avatar
      Join Date
      Mar 5th, 2005
      Location
      SoCal
      Posts
      8,056
      Vehicles
      '00 Boxster Wannabe
      05-19-2009 09:07 PM #39
      Quote, originally posted by Shomegrown &raquo;
      I guess I assumed some here could figure out how internal EGR works.
      Basically during the exhaust stroke, the intake valves are opened early before the exhaust is finished exiting the combustion chamber. This forces dirty exhaust, oil, and unburned gasoline hydrocarbons back up into the intake valves and intake ports.
      It has nothing to do with when fuel is injected into the combustion chamber because EGR function occurs later during the end of the exhaust stroke.
      *edit* - To clarify your other point, the injection event doesn't take place late on gasoline engines. You might be confusing things with diesels which inject after the intake valves are closed and during compression.
      On gasoline direct injection engines, you are spraying while the valves are open which means some spray ends up on the valves. Watch the video.
      http://www.youtube.com/watch?v=qd90yHlmfS4
      http://www.youtube.com/watch?v=73BrXCsbd64
      Modified by Shomegrown at 1:49 AM 5-20-2009

      is the condescending tone really necessary?
      Also, I doubt gas grade has anything to do with the problem. Audi RS4 owners don't cheap out on the type of gas they buy.
      Quote Originally Posted by iamnotemo View Post
      ...I am jealous of your shift knob. That is a shape I love.
      Quote Originally Posted by elementpb View Post
      your mom sounds like my kind of lady. is she single and/or discrete?

    15. Member Shomegrown's Avatar
      Join Date
      Feb 26th, 2002
      Location
      Detroit
      Posts
      18,890
      Vehicles
      Current: Audi S4, Q5 TDI quattro, Porsche Boxster S, Ford F-150 FX4 4x4
      05-19-2009 09:12 PM #40
      Quote, originally posted by greatfox &raquo;
      is the condescending tone really necessary?
      Also, I doubt gas grade has anything to do with the problem. Audi RS4 owners don't cheap out on the type of gas they buy.

      It wasn't meant to be condescending.
      If there's a post with a picture of a blue car and someone says "there's no way that car's blue!"....
      What are you going to say to them?
      I didn't say that was the primary cause. I did say it was a contributing factor. Fuel does contact the backsides of the valves. Fuel with better detergent properties will leave fewer deposits.
      There are a number of factors that cause this issue.

    16. Member adrew's Avatar
      Join Date
      Aug 14th, 2003
      Location
      Texas
      Posts
      13,692
      Vehicles
      '12 Yaris, '14 Mirage, 2.7 liters total
      05-19-2009 09:52 PM #41
      So does this also happen to Atkinson- and Miller-cycle engines?
      Quote, originally posted by Wikipedia &raquo;
      In the Miller cycle, the intake valve is left open longer than it would be in an Otto cycle engine. In effect, the compression stroke is two discrete cycles: the initial portion when the intake valve is open and final portion when the intake valve is closed. This two-stage intake stroke creates the so called "fifth" stroke that the Miller cycle introduces. As the piston initially moves upwards in what is traditionally the compression stroke, the charge is partially expelled back out the still-open intake valve. Typically this loss of charge air would result in a loss of power. However, in the Miller cycle, this is compensated for by the use of a supercharger.
      A key aspect of the Miller cycle is that the compression stroke actually starts only after the piston has pushed out this "extra" charge and the intake valve closes. This happens at around 20% to 30% into the compression stroke. In other words, the actual compression occurs in the latter 70% to 80% of the compression stroke. The piston gets the same resulting compression as it would in a standard Otto cycle engine for less work.
      Improving the signal-to-noise ratio

    17. Member fbobberts's Avatar
      Join Date
      Jan 12th, 2008
      Posts
      1,701
      Vehicles
      '11 335d, '00 M5
      05-19-2009 10:10 PM #42
      Quote, originally posted by Slickvic &raquo;
      Word in the 2.0 FSI forum is that the root cause is from the PCV valve sucking oil into the engine and collecting on hot intake valves.

      This is a total German car sweep FTW (6 cyl + 4 cyl turbo) when this is a known issue in both your cars.


      Modified by fbobberts at 7:12 PM 5-19-2009
      Touareg Hybrids are pretty nice, and the warm fuzzies I felt while driving the hybrid was actually the fingers of all of the German tax payers trying to reach into my wallet to get their money back. (Brendan@bwalkauto)

      Quote Originally Posted by Wellington P Funk View Post
      Simpleton? I think you've both got me mixed up with someone else.

    18. Member s-rocc's Avatar
      Join Date
      Nov 26th, 2001
      Location
      reassembled in a garage, pa
      Posts
      9,282
      Vehicles
      bunch of old german junk
      05-19-2009 11:15 PM #43
      Quote, originally posted by greatfox &raquo;
      is the condescending tone really necessary?
      Also, I doubt gas grade has anything to do with the problem. Audi RS4 owners don't cheap out on the type of gas they buy.

      psst, you're talking to an enginner who designs engines for a major automobile producing corporation.
      i realize that you know it all, i've seen you in action in the a2 forum, but i'd tend to trust him on this.
      this / is / where / your / sweet / mods / go

    19. Member NOTORIOUS VR's Avatar
      Join Date
      Sep 24th, 2002
      Location
      Toronto
      Posts
      4,066
      Vehicles
      D3 A8 4.2 - E36 Turbo
      05-19-2009 11:27 PM #44
      Quote, originally posted by greatfox &raquo;
      Audi RS4 owners don't cheap out on the type of gas they buy.

      LOL... ya ok
      You know how many people I've seen put 87 into high performance cars? Most people don't care at all. I bet you most people think high octane gas is a 'gimmick'
      SCHNELL ENGINEERING · BLOG · STANDALONE ECUS · TUNING · DYNO · WIRING · PARTS · VEMS

    20. Member greatfox's Avatar
      Join Date
      Mar 5th, 2005
      Location
      SoCal
      Posts
      8,056
      Vehicles
      '00 Boxster Wannabe
      05-20-2009 12:16 AM #45
      Quote, originally posted by s-rocc &raquo;
      psst, you're talking to an enginner who designs engines for a major automobile producing corporation.
      i realize that you know it all, i've seen you in action in the a2 forum, but i'd tend to trust him on this.

      He's right, I'm wrong. Is that what you want?
      Regardless of the valve overlap, the problem still exists. And it is widespread. I'm just trying to find the root of it because I'm interested in buying a car with DI.
      P.S. I'm a chemical engineer and as such, I have no trouble understanding and learning the technical aspect of matters like this.
      Quote Originally Posted by iamnotemo View Post
      ...I am jealous of your shift knob. That is a shape I love.
      Quote Originally Posted by elementpb View Post
      your mom sounds like my kind of lady. is she single and/or discrete?

    21. Member
      Join Date
      Sep 28th, 2001
      Location
      Abilene, Texas
      Posts
      3,325
      05-20-2009 12:30 AM #46
      How about some old school remedies like marvel mystery oil or some type f transmission fluid?


      Modified by Crash6 at 7:02 AM 5-20-2009

    22. Member _GoatPunishment_'s Avatar
      Join Date
      Mar 28th, 2002
      Posts
      3,269
      Vehicles
      2011 Mustang GT
      05-20-2009 01:00 AM #47
      Quote, originally posted by adrew &raquo;
      So does this also happen to Atkinson- and Miller-cycle engines?

      As for the Atkinson engine, yes kinda... Because the intake valve is held open on the compression stroke a high volume of air is forced back into the intake. Toyota tried to help this by putting a large surge tank on the manifold. What the surge tank actually does is store oil, unburnt fuel, carbon deposits. When the build up gets high enough the engine will fail to start because it can't burn it. I have not seen buildup on the valves yet.
      That heavy carbon build up on the valves will cause burnt valve issues. Toyota's 3.4L V6 has some issues with carbon buildup on the valves. It's usually known once a valve is burnt bad enough to leak causing misfires. The carbon buildup won't allow the valve to spin and cool. The carbon will actually burn into the valve face.

    Page 2 of 2 FirstFirst 12

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •