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Thread: Leaky Injector Seals?

  1. #1
    My friends think I'm nuts jawn101's Avatar
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    Leaky Injector Seals?

    Hey everyone, me again. So now that the idle motor issue is solved, I’m on to the remaining vacuum leak - injector seal #5. I’ve never had any problems with this before, but during a recent valley job I replaced all 6 seals and clips since they were still OEM. It seems that #5 never actually seals. I used the seals from DMCH originally, but just today received a bag of replacements from DeLorean Go that are a slightly softer rubber. Neither actually seals, though. The seal is in place firmly around the injector and the clip is all the way down, but if you pull up slightly on the injector you can hear it start sucking air and the idle goes to crap.

    Here’s a video of the issue (sound on)


    https://youtu.be/UGU1QeN4NIk

    Anyone have any experience with injector seals, know why this might happen, any suggestions? Stronger clips? Thicker seals? A big gob of RTV?
    Jon
    1981 DMC-12 #02100. July 1981. 5-speed, black, grooved w/flap.
    restoration log, March 2011 to present
    full and detailed photo restoration log

  2. #2
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    The clips are only to prevent the injectors from coming loose or popping out if there is a backfire. If the cup the injector fits into is bent it can leak. You can wrap the seal with some Teflon tape to help seal it.
    David Teitelbaum

  3. #3
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    Injector O-Ring seals

    @jawn101

    I had this very problem when I purchased my car 27 Years ago. I used late 70's VW injector seals/o-rings when I noticed way too much movement of the injectors(in metal holder)

    I replaced the injector o-rings and all small vacuum hoses to fix poor idling, it worked perfectly and I also coated those o-rings with a very small dab of RTV to completely seal any air that could get past these seals.

    If I have to ever replace those seals or an injector, it might be a little difficult to get out but for 27 years they still seal and I have an excellent idle, except the small 'hunting' when cold start up.

  4. #4
    My friends think I'm nuts jawn101's Avatar
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    Thanks, folks. Not sure how the cup could be bent but anything is possible at this age I guess. Do I need to find the fuel safe Teflon tape or will the standard white stuff work? I guess if there’s actually gas at the seal there are bigger problems than the tape itself. I’m just scared of that stuff shredding and ending up in the cylinders.
    Jon
    1981 DMC-12 #02100. July 1981. 5-speed, black, grooved w/flap.
    restoration log, March 2011 to present
    full and detailed photo restoration log

  5. #5
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    I use the regular white stuff but usually only as a temporary fix till the seals can be replaced. It doesn't shred up because you are not applying it to threads.
    David Teitelbaum

  6. #6
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    Tape the outside of the seal not the injector. Spray carb cleaner on the injector while running to make sure it's not leaking air.

  7. #7
    My friends think I'm nuts jawn101's Avatar
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    Solid suggestion, but have to give credit to Clint as he came up with it right away

    Wrapped the injector seal with two wraps of yellow teflon tape (I was at the store anyway and it was 2 bucks, figured why not) and replaced the brand new clip with the cleanest of my OEM ones. It has a slightly different shape than the new ones and felt a lot more positive when I snapped it on. The injector no longer shifts in the hole and that air leak is gone.

    Now the question is why the idle has drifted skyward ever so slightly again.
    Jon
    1981 DMC-12 #02100. July 1981. 5-speed, black, grooved w/flap.
    restoration log, March 2011 to present
    full and detailed photo restoration log

  8. #8
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    Because if you did indeed eliminate the last vacuum leak and you're idling using the idle control valve and the idle speed control screw on the throttle plate you are
    to the point of being able to actually adjust the idle. Start with the idle screw.

  9. #9
    My friends think I'm nuts jawn101's Avatar
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    Quote Originally Posted by cdrusn View Post
    Because if you did indeed eliminate the last vacuum leak and you're idling using the idle control valve and the idle speed control screw on the throttle plate you are
    to the point of being able to actually adjust the idle. Start with the idle screw.
    I actually did exactly that on Dave M’s advice; backed the idle screw all the way out (damaged it in the process because I’m stupid, but will replace it next time) and then put it in ever so slightly until the idle raised, then backed it back out again. I think it’s finally settled down!
    Jon
    1981 DMC-12 #02100. July 1981. 5-speed, black, grooved w/flap.
    restoration log, March 2011 to present
    full and detailed photo restoration log

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