TTAC: Ask An Engineer: GDI Problems In A Nutshell

Discussion in 'Other Cars' started by cwerdna, May 4, 2012.

  1. cwerdna

    cwerdna Senior Member

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    Ask An Engineer: GDI Problems In A Nutshell | The Truth About Cars

     
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  2. usbseawolf2000

    usbseawolf2000 HSD PhD

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    I wonder if GDI will be suitable for PHVs. It seems the answer is no.
     
  3. Skoorbmax

    Skoorbmax Senior Member

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    I think I recall reading that Audi was having a lot of potential issues with this. Also, maybe unrelated, I'm not sure, but the article mentions fuel pumps, a fairly recent BMW with a high pressure fuel pump has found absurdly high failure rates. I saw one guy online on his third one by around 10k miles and it was felt like the north american gas was responsible in part for this.
    http://www.autoobserver.com/2011/06/direct-injection-fouls-some-early-adopters.html
     
  4. Trollbait

    Trollbait It's a D&D thing

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    The metal of concern with ethanol is aluminum. It can remove the oxide film on the metal. Aluminum is actually quite reactive, and readily forms an oxide on contact with air. This 'rust' is bonded to the metal and what gives aluminum it's corrosive resistant properties. Besides bases, don't put lye in an aluminum pot, ethanol is one of the few things I've heard of that can corrode aluminum.

    But most, if not all, modern aluminum block engines use iron/steel sleeves in the cylinders. The other engine parts the fuel comes in contact with is steel and even stainless in places.

    Maybe the higher fuel pressures can exacerbate the issues of ethanol all engines can have. Any manufacturer with experience with diesel already has experience with high pressure fuel systems though.

    If I get a car with direct injection, I'd install a PCV catch can. I considered it for every car I've had though. Had a simple one on the Ranger, and it caught about a table spoon of oil every week or two. Sounds like some GDI engines don't have any carbon issues, but why burn oil that should be in the crankcase.

    The comments to the OP article mention the fuel pumps and other issues. It seems to be brands without a reputation for super reliability to begin with.