air leaks, fuel leaks, return system...questions

Discussion in '6.9L IH & 7.3L IDI Diesels' started by coletrain777, Jan 6, 2011.

  1. coletrain777

    coletrain777 Full Access Member

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    Few questions:

    1. Can a small leak in the fuel return lines system (or injector line to injector) cause a stumble/miss at low rpm (1k-1.5k)? talking about a leak that is small enough not to be seen, but I assume is there.

    2. Is it beneficial to use teflon tape so something of the sort to seal the injector line to the injector (small amount). Especially if the threads on the injector or injector line fitting are semi-buggered up?

    3. I know a lot of people have problems with the return line o rings shrinking (or not sealing well) and causing air intrusion/leaks in the return system. Do you think a fuel additive like Power Service (grey bottle or white bottle), or Howes would help to keep not only the fuel system lubricated but also keeps the rings from shrinking?

    4. Is there any fuel additive that could be run that would slightly swell the o-rings to cause them to seal better?

    5. Would there be any benefit to using worm-gear style clamps on the return line setup instead of the regular red spring style clamps? I know that you would have to take care not to crank on them extremely hard so that they wouldn't cut into the hose, but it seems like you can be better assured that the clamp is tight with these (I hate spring style clamps... don't know why).

    6. What type of clear hose are you guys using to check for air intrusion in your system. I know that most run it from the filter head to the 1st return line, but are you using some form of clear fuel line or chemical resistant line? If so, where are you getting it? It would seem to me that regular clear tubing would be eaten up by diesel fuel fairly quickly.

    Some of these questions apply to my truck, and some are just for my personal information. Any informative responses are appreciated!
     
    Last edited: Jan 6, 2011
  2. joe f350

    joe f350 Full Access Member

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    get a return line kit do them all at once cause once u disturb one the others will start to leak it is easyer to do all the injectors at wonce
     
  3. Agnem

    Agnem Using the Force! Staff Member Supporting Member

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    1 - Once an engine is running, any leaks in the return line system will not effect run quality. Only during shutdown is a return line leak an issue.

    2 - You cannot use any sealant. Replace anything that is munged up.

    3 - A new return line kit is your solution. A properly installed kit should last for years and years.

    4 - swelling = softness. Not good.

    5 - I've seen it done, but honestly I don't think there is any benefit. See #3.

    6 - run of the mill clear vinyl tubing will work for a short time. Don't leave it in place for weeks on end.


     
  4. coletrain777

    coletrain777 Full Access Member

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    So what about a tiny amount of seepage between an injector line and the injector (at the fitting), would this effect run quality? The leak is very insignificant, I can just notice a minor amount of fuel around the fitting after driving for a while. The problem is that the injector line fitting is tight on the injector (no more tightening to be done). How would I fix this???
     
  5. coletrain777

    coletrain777 Full Access Member

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    Return line kit is new, just wondering about the setup.
     
  6. FordCoalRoller

    FordCoalRoller IDI Probbie

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    I replaced the return line kit on mine because i was having a starting problem and they were leaking. They are not leaking now but still have the issue it looks like the injection pump itself is leaking around the advance mechanism. I only have a problem with studdering in that rpm range when i let my fuel and close it E and the fuel is sloshing around.
     
  7. oldmisterbill

    oldmisterbill Grumpy Old Man

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    I wouldn't advise any sealant on the high pressure lines.If it won't seal check to see if the injector is bunged up or the flared fitting in the line.If it's the line replace it-if its the injector replace that. Or replace them both.

    One thing have always done is make sure the return lines between the injectors dont have a curve in them caused by being a little over length if I have to have a curve I make a loop to take pressure off the t fitting & O-ring.In my opinion it makes a safer seal that will last. The spring clips are fine I don't think I have evr seen a leak in a decent set of lines & good T fittings.
     
  8. BigRigTech

    BigRigTech Diesel junky

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    The clear the vinyl line is tough, mine has been on there for almost a year - just the same as it was when I put it on.
     

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