12.7 power problem

Discussion in 'Freightliner Forum' started by saddleup, Sep 17, 2014.

  1. saddleup

    saddleup Light Load Member

    281
    137
    Sep 30, 2011
    magnolia, ky
    0
    2003 freightliner 12.7 non-egr in-frame 200,000 ago new 6 pack of injectors in Feb this year. Drove from Columbia, mo to Troy, Il ran fine, next morning started up and missing and shuttering and shaking so bad can;t hardly get took off empty. went to evensville, in sat for the weekend Monday started up and take off still missing but not as bad, but got worse during the day. Did a injector cut out today 1,2,3,6, can't tell any difference when cut out, number 4 makes a little difference and number 5 makes all the difference when cut out. Turbo only at 2 psi. it is always worse later in the day. Mech that did injector install won;t tear into it says not the injectors but instead a electrical problem. any ideals? Oh and no fault codes
     
    Last edited: Sep 17, 2014
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  3. fortycalglock

    fortycalglock Road Train Member

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    Jun 25, 2011
    Tourist Town, FL
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    Check all your fuses and terminals for corrosion for the power wires going to the ECM. Most likely the injector or harness. Did you have a new injector harness put in with the 6 pack? What kind of mechanic won't pull the valve cover to check the terminal connections??? Recently, I had mine start sputtering, no real power and CEL on hard acceleration, it ended up being a broken terminal on the injector harness. I replaced the harness when I did the 6 pack, but the head was off for a head gasket in June so I think that contributed to my problem.
     
  4. baha

    baha Road Train Member

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    Jul 25, 2013
    ga
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    Replace the wiring harness that leads to inj. under valve/cover 200$ part,
     
  5. Powder Joints

    Powder Joints Subjective Prognosticator

    7,162
    6,731
    Sep 25, 2007
    Rosamond, SoCal
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    Bad Fuel, Check your filters.
     
  6. GrapeApe

    GrapeApe Road Train Member

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    Jan 7, 2013
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    Any check engine lights? If it were that bad due to a wiring problem, you'd proably get codes. Check fuel filters 1st. Then check for air in the return line, run it in a bucket and stab the throttle a few times to see if your getting compression in the fuel system.

    Did you do a cut out at both idle and 1000 rpm? When injector o-rings go, it can skew the #'s. If a cylinder shows weak, it could be from compression getting past an o-ring of a cylinder fired before it. The weak cylinders will ususally change at a different RPM if air in the fuel is the cause or they'll be inconsistent when you run 3 tests back to back.
     
  7. saddleup

    saddleup Light Load Member

    281
    137
    Sep 30, 2011
    magnolia, ky
    0
    Replaced fuel filters and no change, will be checking return line pressure tomorrow, don't see any bubbles in tanks but seems to have fogs like steam coming from tanks. Took for test drive after filter change and smoked some and popped back like back fire
     
  8. QUALITYTRUCK

    QUALITYTRUCK Road Train Member

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    1,722
    Jun 14, 2009
    romulus,mi
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    sounds like tight valves/and or improper injector height adjustment.height should be 82.1 measured with correct height tool.there is a proper "circle"method to follow when adjusting valves and injectors.good luck.
     
  9. saddleup

    saddleup Light Load Member

    281
    137
    Sep 30, 2011
    magnolia, ky
    0
    No engine codes, replaced the injector wiring harness and no change, have all the proper gauges for setting injectors and valves, injectors leaked off over night also, took it and dropped off to mechanic yesterday, he wants another cut out test ran, let him pay for it.

    this is the last time i let anyone work on my truck again, next time i will let the rain stop or have my shop built. If its broke under warranty fix it.
     
  10. GrapeApe

    GrapeApe Road Train Member

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    Jan 7, 2013
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    Good luck, warranty is usually a battle, almost guaranteed if it is not a dealer. I'd ask for the print out of the cutout test. The "proper" way is 3 consecutive tests at idle, average the results, then 3 at 1000 rpm and average the results. No more than 0.2 difference between high and low on each test. Most warranty claims that are denied are the fault of the installer, improper diagnosis or procedures. Have your ducks in a row and get copies of everything, many shops will just pass that cost on to the customer in some way. Integrity is not what it used to be in the world today.

    When I pull in injectors, I use a mighty-vac pump and a short hose on the end of the injector, if it doesn't hold a vacuum, it's leaking down. I always note that on the warranty claim. It seems to confuse the warranty dept. and they call me. When you can actually talk to a person, you double your chances of getting warranty. But that's not up to you at this point, the shop that did the work has to deal with warranty.
     
    x#1 Thanks this.
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