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A smokin' Cummins - Help!!!!

Discussion in 'Trucks' started by CJLennon, Mar 20, 2010.

  1. ramdieselsmoke

    ramdieselsmoke Member

    Joined:
    Mar 25, 2010
    Messages:
    7
    Location:
    CT
    its a cummins its supposed to smoke...
     
  2. bolt thrower

    bolt thrower Well-Known Member

    Joined:
    Oct 26, 2007
    Messages:
    105
    Occupation:
    Tractor Fixer
    Location:
    Flagstaff AZ
    Hi Chris, I wish I could tell you which way the timing is with the indicator readings. Its been nearly 20 years since I timed one with the cummins tool, and I dont have a service manual anymore either. Seems like TD25 has one, maybe he is more up on the procedure to. The only reason I am very familiar with how the system works is, I am like you, If I don't know how something works it bugs me. I have invested alot of time learning this fuel system, as well as alot of other makes and models (I am mainly a Cat guy). I have a pretty cool old ntc-250 operators guide that actually has some great pictures and details about fuel system theory of operation. Cummins used the PT fuel system from the days of the small cam, up until the big cam 4 in the late 1980's. Not sure if you are in the mountains or not, the cummins' Ive been around were used @ 9500 ft. elevation, you should see how they smoke up here!!! Our ski area here has a chairlift with a cummins 555 for backup power. One summer morning they were running it before they did an oil change, and the forest service showed up cuz they thought there was a fire!
     
  3. CJLennon

    CJLennon Well-Known Member

    Joined:
    Jul 24, 2009
    Messages:
    62
    Location:
    Chapel Hill, NC
    Hey B/T,
    Thanks again for everything. If you graph how the cam works with respect to time, moving the graph to the left (advanced timing) causes the distance between .2032 BTDC and the 90 degrees ATDC decreases. So, if my numbers are low, then the timing is advanced. Opposite if the numbers are high. Just some out-loud thoughts. Thanks again for everything, especially the stories. Very entertaining. I hope life treats you well my friend and if you are ever in the Carolinas, look me up.

    Chris
     
  4. CJLennon

    CJLennon Well-Known Member

    Joined:
    Jul 24, 2009
    Messages:
    62
    Location:
    Chapel Hill, NC
    Hey Folks,
    I haven't updated this post in a while because, believe it or not, the motor stopped smoking. In fact, it is worse, it doesn't pull well at all. So, now I have the opposite problem. So, I went back through the motor and rechecked everything and made sure all was correct with valve, injector travel, etc. I even sent the pump out and had the fuel pressure increased by using a #10 barrel instead of a #7. (I think Igot those numbers right.) The only thing different between before (smoking bad) and now (no smoke, no power) is the injectors. So, we put everything back to how it was when it smoked (yeah, we messed around with the injector travel) except for these new injectors. So, my question to you folks is, could we have gotten a wrong set of injectors and, if so, could it cause the wrong fuel amount to be shot into the engine causing a real sluggish engine that used to pull like nothing else I have ever seen? I just can't understand what happened to the fuel? This is a PT-370 engine. Any thoughts on this? Thanks again to all for their help.

    Chris