What do these hoses on the injectors do?!!! - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• What do these hoses on the injectors do?!!! by vwt4 on 28 Dec, 2008 16:02
• These ones!
  
  
  
  
  and is there a particular material they should be made from?
  These are the same rubber hoses as for my vacuum lines?
  
  thanks
• #1 by fairweather on 28 Dec, 2008 16:08
• Those are the fuel return lines, from the injector on the right the hose will return to your IP/tank. They should be rated for diesel use or viton if running biodiesel.
• #2 by vwt4 on 28 Dec, 2008 16:48
• Quote from: "fairweather"

  Those are the fuel return lines, from the injector on the right the hose will return to your IP/tank. They should be rated for diesel use or viton if running biodiesel.

  
  
  Thanks fairweather  
  
  I had rather a feeling they were for diesel but am 99% positive they are vacuum hoses that are installed?
  
  I better look into getting some replacement fuel line I suppose  :?
• #3 by jtanguay on 28 Dec, 2008 16:49
• yea that fuel return hose can double up as vacuum hose as well
  
  looks like you could have routed those lines a little better, but it will work like that.  one thing to keep in mind is that the ends will never re-seal the same as the first time.  so you need to cut a bit off if you remove them for whatever reason.  they might hold, but they usually end up getting all wet and leak diesel all over.
• #4 by vwt4 on 28 Dec, 2008 17:12
• Quote from: "jtanguay"

  yea that fuel return hose can double up as vacuum hose as well
  
  looks like you could have routed those lines a little better, but it will work like that.  one thing to keep in mind is that the ends will never re-seal the same as the first time.  so you need to cut a bit off if you remove them for whatever reason.  they might hold, but they usually end up getting all wet and leak diesel all over.

  
  
  Thanks jtanguay
  
  I have actually used new vacuum hose and made these return lines....because its a new cylinder head I had to swap all parts off my old one.
  
  BUT, the lines on the old one looked precisely like vacuum lines (the same stuff) and some of the cover was peeling off them so I thought I would just make new ones..
  
  I copied the old ones pretty much identically length wise etc
  
  please tell me how I could improve them so I know for future.
  
  Do I need to go and try and find some specific derv return line? VW agent is out so it would have to be a motor factor who probably wil only have petrol fuel hose (much thicker from the stuff Ive used)
• #5 by veedubcanuck on 28 Dec, 2008 18:40
• Just a warning. I used vacuum hose once on there and it ate the rubber. The lines swelled all up and leaked after a day. Alot of vacuum lines are just rubber and diesel eats rubber.
• #6 by Duster 5.9 on 28 Dec, 2008 21:01
• you can get them from a tractor dealer too. duetz has them. also you have the end plug on the wrong end incase you didn't notice.
• #7 by Smokey Eddy on 29 Dec, 2008 01:57
• you're doing an aaz upgrade too! (im doing the same)
  those lines there are fine to use are they not?
  diesel doesn't have the same rubber eating attributes anymore apparently?
  or ... maybe just rad hose is made out of something different these days.
  I asked a question a while back about diesel eating coolant hoses and the diesel doesn't do it anymore.
• #8 by dillenger1 on 29 Dec, 2008 03:26
• If theyre not diesel rated i wouldnt use them.it would be a pain to have to drive home 100 miles with a blown return hose,fuel spitting everywhere.
• #9 by jtanguay on 29 Dec, 2008 04:44
• Quote from: "vwt4"

  Quote from: "jtanguay"

  yea that fuel return hose can double up as vacuum hose as well
  
  looks like you could have routed those lines a little better, but it will work like that.  one thing to keep in mind is that the ends will never re-seal the same as the first time.  so you need to cut a bit off if you remove them for whatever reason.  they might hold, but they usually end up getting all wet and leak diesel all over.

  
  
  Thanks jtanguay
  
  I have actually used new vacuum hose and made these return lines....because its a new cylinder head I had to swap all parts off my old one.
  
  BUT, the lines on the old one looked precisely like vacuum lines (the same stuff) and some of the cover was peeling off them so I thought I would just make new ones..
  
  I copied the old ones pretty much identically length wise etc
  
  please tell me how I could improve them so I know for future.
  
  Do I need to go and try and find some specific derv return line? VW agent is out so it would have to be a motor factor who probably wil only have petrol fuel hose (much thicker from the stuff Ive used)

  
  
  the old diesel and maybe biodiesel will eat away at the vacuum hose most likely. but i doubt the new diesel will do much to it (still a possibility though)
  
  the general idea is that both of the fuel return nipples on the injector are pressurized, so making sure that the 1st one has one capped and one flowing to the 2nd will work (and so on).  doesn't matter which nipple is capped.  either way, your setup will work just fine.
  
  i've used the fuel return hose as vacuum without any issue, but i've never tried the vacuum hose as fuel return... be warned that it might leak.
• #10 by vwt4 on 29 Dec, 2008 08:54
• Quote from: "jtanguay"

  Quote from: "vwt4"

  Quote from: "jtanguay"

  yea that fuel return hose can double up as vacuum hose as well
  
  looks like you could have routed those lines a little better, but it will work like that.  one thing to keep in mind is that the ends will never re-seal the same as the first time.  so you need to cut a bit off if you remove them for whatever reason.  they might hold, but they usually end up getting all wet and leak diesel all over.

  
  
  Thanks jtanguay
  
  I have actually used new vacuum hose and made these return lines....because its a new cylinder head I had to swap all parts off my old one.
  
  BUT, the lines on the old one looked precisely like vacuum lines (the same stuff) and some of the cover was peeling off them so I thought I would just make new ones..
  
  I copied the old ones pretty much identically length wise etc
  
  please tell me how I could improve them so I know for future.
  
  Do I need to go and try and find some specific derv return line? VW agent is out so it would have to be a motor factor who probably wil only have petrol fuel hose (much thicker from the stuff Ive used)

  
  
  the old diesel and maybe biodiesel will eat away at the vacuum hose most likely. but i doubt the new diesel will do much to it (still a possibility though)
  
  the general idea is that both of the fuel return nipples on the injector are pressurized, so making sure that the 1st one has one capped and one flowing to the 2nd will work (and so on).  doesn't matter which nipple is capped.  either way, your setup will work just fine.
  
  i've used the fuel return hose as vacuum without any issue, but i've never tried the vacuum hose as fuel return... be warned that it might leak.

  
  
  Thanks guys.
  
  i have been out and bought some specific diesel return line hose. it looks almost identical to the stuff I have used, but who knows. Maybe my vacuum line would have failed!!! Not worth it for $10
  
  I have also adjusted the hose routing slightly so the cap is on nipple  1 and so on. I think it looks neater and seeing as I had to take them off anyway...!!
  
   thanks