Leaking return lines - page 1 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Leaking return lines by rodpaslow on 19 Jul, 2010 09:36
• it was suggested I start a new topic
  
  A couple problems I need help with I have a new 1.6TD newly rebuilt 450 Km on a new engine with the intake blow off valve blocked off (a plug from Giles) a Giles pump and injectors redone by him as well.  The biggest problem I think is with the fuel , but only able to build 12psi boost, but that can be dealt with later..
  
  I'm using the stock throttle body pump in the fuel tank to push fuel to the engine compartment and a regulator to regulate fuel pressure down so it's just slightly coming out of 1/4 fuel line.  It's almost just dripping out the pressure and amount of fuel is so low.  New injector return lines are on the injectors.  The #4 injector has the return line to the pump and the #1 has the plug.  The line between #2 and #3 is leaking pretty badly as the front of the engine is wet with diesel.
  
  I have added an electric return pump as well thinking (was a gas car) I can push the return fuel back to the tank.  I'm out of ideas as I changed the return line to another thinking it may be plugged, no change.  What will stop this leaking?
• #1 by Rabbit on Roids on 19 Jul, 2010 09:39
• i would get rid of the pressure regulator, its just impeding your flow. pressure feed that bad boy. tyler said they can handle PLENTY of inlet pressure and still run correctly.
• #2 by rodpaslow on 19 Jul, 2010 11:44
• Will that help or the leaking return lines?  it was a throttle body pump when it was gas, so it won't see tremendous pressure - only about 22 psi or so.
• #3 by Quantum TD on 19 Jul, 2010 12:40
• What are you using for return hose? If it's standard rubber crap-a$$ vacuum hose from your local parts store, it's probably too big.
  
  The return hose should be 3.2 x1.9mm with braided cloth on the outside to prevent swelling.  If you don't have that, or are not sure, get the right stuff and it should solve your problem.
  
  If it doesn't solve your problem, then perhaps the overflow nipples are broken on the injectors, or you're actually leaking out of the main connection and it's dribbling down the return hose. Check the nipples on the hard-steel lines. If the tips look like pancakes, then maybe it's time for new injector pipes.
• #4 by Rabbit on Roids on 19 Jul, 2010 12:49
• i run toyota vacuum lines for my injector return lines.. it works very well for me. not too big, and seals up good. doesnt seem to have a problem with the diesel weakening it..
  
  as for the fuel pump, if its a gasser car, it has 2 fuel pumps, a high pressure one outside the tank in a reservoir, and a low pressure one inside the tank.. delete the high pressure one and feed the IP with the low pressure pump at full pressure. it will act as a lift pump, and lengthen the life of fuel filters..
  
  the in tank pump puts out about 5-7 psi.
  
  changing how much fuel the pump has coming into it is just messing with timing advance and possibly starving the pump. the return line is whats causing leaks here right? not the feed line? if its leaking from the return lines, dont fix the feed lines, fix the return lines. my bet would be a tiny hole in a line, or a crack, or something like that..
• #5 by rodpaslow on 19 Jul, 2010 13:59
• I'm running the proper cloth braided line as per vw use.  I follow what VW used or I'm just aking for problems when it somes to that.  So I don't think it's the line that fits the nipple.  All these injectors were sent to Giles for rebuild so I'm pretty sure he would check for cracks between the injector body and the nipple, but I will double check that!
  
  It's actually not the small return line that goes to the pump - it's a line between injector cyl #2 and #3 that is leaking.  The small return line is good to the pump is fine, but both #2 and #3 injectors are leaking - should I check that there is some fuel coming through the small return when it's running?
  
  I didn't bend them installing them as I have a snap on injector socket and when putting the return line on I was careful.  I will remove the higher pressure pump as you suggest and try it without the regulator - that should be easy to change tonight. 
• #6 by Rabbit on Roids on 19 Jul, 2010 15:42
• i still think you have a feed line restriction somewhere. take the cap off your fuel tank, unless its plumb full, and blow some compressed air down the return line.. there should be no leaks. are all your small lines brand new? try swapping the line between 2 and 3 with the line between one of the other injectors. do they start leaking when you install the line between 2 and 3 on the others?
• #7 by rodpaslow on 19 Jul, 2010 20:37
• With this being a new engine I replaced all the hoses on the injectors.  The return lines, the braided cloth hoses are brand new. 
  
  This is a 96 and I was able to do a bit of work this evening and the car just has a single pump that's in the tank.  It has a gas filter that's next in the line that I have not removed.  After the gas filter the line goes to the engine bay where I have the regulator, diesel filter and then inj pump.
  
  I removed the cover to the pump in the tank and have just taken the lines off the pump for now.  I don't have access to an air compressor but I do have an air tank so I will see if there's some kind of blockage in the fuel line going back to the tank.  I suppose I can test it by me blowing in it to see if it is blocked first.
  
  Is the return banjo bolt that connects to the return side of the injector pump the one with the tiny hole in it - just makin sure.
• #8 by rodpaslow on 19 Jul, 2010 20:55
• I have one other question - the banjo bolt looks like it has some kind of mechanizm inside it.  Is there some kind of check valve or something that can plug?
• #9 by rodpaslow on 19 Jul, 2010 21:06
• Someone mentioned there is a filter in the return banjo bolt.  Is there a way to remove it without damaging it so a person can clean it.  Will VW have a new one if I damage it??
• #10 by Rabbit on Roids on 20 Jul, 2010 08:28
• the out bolt has a restriction in it, that is not causing your return line leak..
• #11 by rodpaslow on 20 Jul, 2010 21:32
• Okay, I took the pump out tonight and the return line had a hose attached to a plastic part that surrounded the gas fuel pump.  The top plastic part that you can take off once you get the plastic nut loose, has two hoses attached to plastic outlets that go out the top and one hose on the tank side attached to the pump and another hose for the return so it returns fuel into the tank.   So I cut the return line hose in the tank, so now it will simply run into the tank, not have to push fuel out to the way.
  
  I tested it with just blowing from the engine by and I didn't have to blow very hard to hear air coming out in the hatch.   I blew about as hard as blowing into a straw with a full bottle or pop or something like that.  I didn't have the intake hoses on yet(so I couldn't run the engine), but I did run the fuel pump and left the return line off.  There was fuel that started running out about a minute or so later.
  
  Once I get proper clamps on my engine for the intercooler piping I will test it.  What needs to be looked at next if it still leaks?  My Dad seams to think that gas cars have the tank pressurized; or is the tank vented in a diesel and gas?
  
  Anyway thanks for the help to this point....
• #12 by Rabbit on Roids on 21 Jul, 2010 09:10
• tanks are NOT pressureized.. not on a VW atleast.. they gotta breath..
• #13 by rodpaslow on 21 Jul, 2010 21:45
• I haven't had a chance to test the return lines leak yet - tomorrow.  I had one quick question about the T3 turbo as I've read a lot of responses from you ROR and others.  One specifically that the wastegate (K14 OR k24 Subject) may have been stuck or slightly open.  Can this happen with the T3 as well because I have a T3?  I have a giles block off plate for the intake, I spent 6 hours last weekend to make sure I had no leak between the turbo and exhaust manifold so that should be fine now.  Getting 12 psi max with the line to the wastegate open to atmosphere.  Wastegate leak?
  
  I have t-bolts securing the hosing to the intercooler and silicone hoses so I'm 90% sure that's not a problem.  I've reviewed lots of messages and this seems like it may be the only thing left to fix?
• #14 by Smokey Eddy on 22 Jul, 2010 09:23
• Yes it could very well be stuck open
  
  as per your leaking returns. When you pull off used/old lines you'll see that they do balloon out a bit where they were slipped onto the nipples. Take something very sharp like an exacto knife (razor blade wire cutters what ever) and cut the ballooned part off of the lines and jam them back on there. This is a good fix so long as you have enough line to still put them back on.