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Another new person with a 6.9

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Bolson400, Sep 19, 2019.

  1. Bolson400

    Bolson400 Registered User

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    A little history. A few months ago I bought an ‘86 6.9L that reads 48,000 miles (likely 148,000 miles). It had the CDR delete when I got it, with an RDT that ran to the rear bumper. Smoked like crazy from the RDT. I put a new CDR on and all the smoke went away, and the blow by seems normal from what I’ve read. Then I noticed a puddle of diesel in the valley pan and found the IP leaking from the weep hole in the bottom. Replaced the IP with a rebuilt one from CarDone (I know I shoulda went with Conestoga or that guy on the west coast, but I needed it now and the money wasn’t there for that). Also replaced the return lines and little plastic caps, fuel filter and oil change. Timing was an issue as I don’t have a way to get it dynamic (?) timed in my area. I started with the timing marks aligned and slowly advanced the timing every couple days toward the passenger side until things seemed right (from what I’ve read). No smoke at idle and normal cruising with a little black smoke when I got on it. I was satisfied. Yesterday after a trip up and down our small mountain, I noticed a diesel smell at stop lights. No noticeable changes in performance. Got home and found the #2 cylinder spitting diesel at each cycle from the base of the steel injector line. No big deal, found a replacement, installed, bled the system and back on the road in a few hours. Satisfied again. This morning I take the truck from Chattanooga to Nashville (about 160 miles). Everything looks and feels good going out of town, smoke is the same as previous days. Then about 60 miles in I see a steady gray/bluish smoke trail behind me that gets worse at higher rpm when under load. No black smoke at all now. It still seemed to feel the same. I stopped and checked for any return line or injector leaks. Everything is dry. It ended up getting much better after another 30 miles or so and even got a little dark gray/black smoke if I gave it a little extra. Then I got off the interstate and in town in lower gears it started the excessive gray/blue smoke even some at idle. The exhaust at idle smells strong like diesel. Had to get back on the interstate and I seemed to clear up a little like before. I could even accelerate from 62 to 75 up a fairly large incline. I get off the interstate and it gray smokes all over like before. What’s happening here? Any help would be appreciated. Also, I’m thinking the injectors are original.
     
  2. dgr

    dgr Full Access Member

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    Welcome

    Could be leaking injectors. You sure that smell isn't antifreeze? Check your oil and make sure the fuel pump isn't mixing fuel into your oil and that is getting sucked into the intake through the CDR and burned.
     
  3. Bolson400

    Bolson400 Registered User

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    Definitely no sweet/antifreeze smell from the exhaust. Other than checking the oil level (which doesn’t seem to be changing) how would I tell if the fuel pump is mixing fuel with the oil?
     
  4. Bolson400

    Bolson400 Registered User

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    It really seems to be running the same way it was before the timing was advanced a good bit. About a quarters width to the passenger side from the factory timing lines.
     
  5. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    Pull the dipstick and smell the oil. If there's fuel in it, you'll be able to smell it.
     
  6. Bolson400

    Bolson400 Registered User

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    Checked the dip stick this morning. No fuel smell in the oil.
    When I found the injector line leaking, it had spewed diesel all over the engine bay. Could there be a pool of diesel somewhere that is contributing to this? I am still really new to these and lost.
     
  7. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I don't believe that any pool of fuel could cause intermittent smoking. Since your engine seems to be mechanicly sound, I'd go back to looking at the injector pump. I know that's not really what you want to hear, but it's a sad fact.
     

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