N14 Celect Plus Misfire and Gray Smoke

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by SpeedyGonzalez, Aug 4, 2019.

  1. AArtemtrk

    AArtemtrk Light Load Member

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    You’ll have to remove rockers, I’m betting that your cam is ok pretty slim chance all lobes wore identically. Just check for bent valves bent pushrods and set your lashes properly, if problem persists I would guess injector or injector harness. Check everything simple before digging too deep.
     
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  3. Working2party

    Working2party Medium Load Member

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    According to the book, the injectors-injector train should handle 25 in-lbs of torque to clear the Injectors, any pumping will clear them, I usually just go by feel. When you think your there, let it sit a few seconds back it off a turn, and bring it back down. If it goes farther you pushed more fluid out, then repeat. If your back to your start, your there. And remember that’s INCH pounds not FOOT pounds.

    As for their previous injector settings, Many people set those injectors “top-stop” method, because the data plate may say T-S. Top stop method sets the injector on the cylinder before the valves and uses only 6 in-lbs (basically just touching) Cummins modified this back to the old way of setting them at the end of stroke to reduce idle loading (smoke).

    They may have been set the old T-S method and your correcting it now.

    When we found the bad cam. We had the engine idling with covers off (Jakes still on) and I thought I visually saw the difference in rocker movement, measured it to confirm it.

    As for the push rods, I think you can fish out the valve rods by backing off the rocker arms, but I think the injector was two big. When was messing with that 444 I got really quick about taking off the rocker assemblies. Before I used the 3rd set of new gaskets, I reused the 2nd set till I had it finally figured out.
     
  4. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    I think I found the C mark, with it lined up both 3 and 4 are loose with four on the end of exhaust/start of intake. Tried setting the injectors on both and again, its bottoming out on the lock nut and not the injector. I really dont know what I'm doing wrong.
     
  5. Working2party

    Working2party Medium Load Member

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    Do a Google search “Cummins N-14 manual lib”

    You should find the Cummins N-14 Shop manual in the listings. The information your looking for is on page 125 it’s step by step.
     
    SpeedyGonzalez Thanks this.
  6. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    I finally got it set, the marks are definelty gone on my accecsory drive or it was replaced with an aftermarket unit without them. I'm about to fire it up and see how it sounds. The manual I have says to set the injector with the valves but that sets the injectors at the top of the stroke so they bottom out mid-engine rotation. The injectors should be set at the bottom if their stroke and not top, ditto.
     
  7. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    Well, the misfire is still there and not much better, the smoke is still eyeburningly full of diesel. I'm going to pull the injector harness off and put it on the other truck, my logic being that if the miss travels to the other truck ita for sure the harness and if it doesn't it's for sure valvetrain related.
     
  8. spsauerland

    spsauerland Road Train Member

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    What fault codes did you have?
     
  9. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    None, the only one I had was on the Kenworth dash with ECU Power Low, charged the batteries and it went away. The engine diagnostic switch lights up the stop engine and check engine lights but they don't flash or turn off, and starting the engine just makes them go away. Got me scratching my head.
     
  10. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    Found this video on youtube of what is basically my exact problem, but this looks like an STC model N14.
    Basically exactly what it sounds and looks like with an exhaust manifold and muffler, the missing and popping isn't as prominent at higher RPMs though.
     
    Last edited: Aug 7, 2019
  11. SpeedyGonzalez

    SpeedyGonzalez Light Load Member

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    Changed the oil and the filters and it only smoked a small cloud on start up. The misfire looks like it's in two cylinders, 3 and 4, would you guys recommend swapping 1 and 3 and see if the misfire follows as a diagnosis? Also found out the switch I thought was for checking codes only tests the lights and doesn't pull flash codes. It also wont go over 1500 rpm in neutral but still no check engine.
     
    Last edited: Aug 8, 2019
    Reason for edit: Added symptom
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