DD looping at idle

Discussion in 'Trucks [ Eighteen Wheelers ]' started by me myself and I, Nov 21, 2016.

  1. me myself and I

    me myself and I Heavy Load Member

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    Oct 5, 2009
    vernon hills,Il
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    Not mine. But I've seen several doing it and assumed there was something wrong. The other day I've parked next to what looked like a new Freightliner and it was doing same thing. I think it had AC on. Is it normal.
     
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  3. 25(2)+2

    25(2)+2 Trucker Forum STAFF Staff Member

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    the road less travelled
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    Certain rpms sometimes induce a lope, usually give it a tap up and it quits the surge, it's right around 900 rpm on the one I drive.
     
  4. magoo68

    magoo68 Road Train Member

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    st malo mb canada
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    It's s fuel pressure regulator on drivers side behind all the fuel lines by filter .. I can't remember the cost to change it but I know it was more if it had a certain bracket in front of it .. truck had way more power and went up 3/4 mpg so it paid itself off quickly 2009 530 hp dd15 didn't have the bracket
     
    Socal Xpress Thanks this.
  5. Animosus

    Animosus Medium Load Member

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    SE Wyoming
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    Quantity control valve on the back of the high pressure fuel pump causes surging at idle. You can watch its current in diagnostic link and see it spiking, at idle it should be fairly consistent.

    [​IMG]

    P/N A0000900069

    They are terrible on 113 BBC cascadia and DD13s. Other than that fairly easy. I've never seen a pump installed without the bracket. And to remove the bracket you need to remove the air compressor coolant line and that bracket. Sometimes the inner fender, high pressure fuel lines and flange.
     
  6. mhyn

    mhyn Road Train Member

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    Northridge, CA
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    I think fuel filter housing must be removed to reach the third bolt on dd15. Which value do you monitor in DiagnosticLink for this particular issue?

    Also that valve cost $800 when the entire reliabilt pump costs $1100. if its time to change it replace the whole pump.
     
    Last edited: Nov 22, 2016
  7. Animosus

    Animosus Medium Load Member

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    SE Wyoming
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    Fuel filter housing does not need to be removed. You do need to remove the high pressure fuel pump bracket to reach the back bolt. Monitor quantity control valve circuit current, should be a value in ma (miliamps).
     
    mhyn Thanks this.
  8. mhyn

    mhyn Road Train Member

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    Northridge, CA
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    I have seen some dd15 also do strange things at idle. One of them I saw was opening and closing egr valve at idle. The actuator was moving the rod back and forward. Have you seen this problem on trucks ? any idea what part could be faulty ?
     
  9. TA Transport

    TA Transport Bobtail Member

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    Jun 25, 2019
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  10. TA Transport

    TA Transport Bobtail Member

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    Jun 25, 2019
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    I replaced fuel quantity valve and it helped but still has a surging idle especially at startup. Seems to smooth out after running a bit but is not right?? Any suggestions
     
  11. mhyn

    mhyn Road Train Member

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    do you have 3 filter system or 2 filter system?
     
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