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Series 60 erratic performance

Discussion in 'Trucks [ Eighteen Wheelers ]' started by lonestar382, Jan 5, 2009.

Page 1 of 2
  1. Jan 5, 2009 #1
    lonestar382

    lonestar382 Bobtail Member

    3
    0
    Jan 5, 2009
    Prosper, TX
    0
    Hello all,

    This is my first post here, and I'm trying to get some troubleshooting info for a 12.7L 60series that I have in my RV. It is a 96' model with the DDEC III computer. I want to describe the symptoms and see if anyone has any ideas.

    After conditions of cruising at a steady speed for extended periods, I am having an issue of no power to accelerate, or pull hills. The bus will typically build boost from 10lbs to 18-19lbs pretty quickly, but at some times, it can take 30seconds or so to even reach 10lbs of boost. After it does reach 10, it will finally accelerate like normal.

    A second symptom to this is the lack of any Jake Brake when this is happening. What I have noticed is if this condition persists, all that is needed to correct is to pull over, shut down motor for 30seconds or so, then restart, and all is normal.

    Sorry to start off as a new member seeking help, but I don't know much about the big OTR motors, so I'm seeking wisdom!!

    Thanks
    Corey
    1996 Bluebird Wanderlodge PT42
    S-60 DDEC III 470/1450
     
    Last edited by a moderator: Feb 6, 2009
    lonestar382, Jan 5, 2009
    lonestar382, Jan 5, 2009
    #1
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  3. Jan 5, 2009 #2
    Peanut Butter

    Peanut Butter Road Train Member

    1,343
    419
    Nov 24, 2007
    PO Dunk Idaho
    0
    I drove a truck with that same motor, when it had that sort of problem the breaker fuse was not making full contact, the worst problem with that motor was a bad injector and then the fuel line on the back of the motor needs a elbow at the back of he motor to keep fuel in the line when not running.. not sure if any odf this will help but i thought i would try to help..
     
    Peanut Butter, Jan 5, 2009
    Peanut Butter, Jan 5, 2009
    #2
  4. Jan 6, 2009 #3
    vegetto05

    vegetto05 Light Load Member

    95
    23
    Jan 5, 2009
    KC, MO
    0
    When hit the accelerator, even when trying to build to that 10#s, does the engine sound like its working? Or does it sound like you're still cruising? I know the engine may be in rear depending on the model...

    I don't see too many Detroits and when I do its usually an overhaul :/
    These things know how blow up better than any of them.
     
    vegetto05, Jan 6, 2009
    vegetto05, Jan 6, 2009
    #3
  5. Jan 6, 2009 #4
    25(2)+2

    25(2)+2 Trucker Forum STAFF Staff Member

    18,750
    45,481
    Sep 18, 2006
    the road less travelled
    0
    They all know how to blow up. Does Cumapart ring any bells.

    Most diesel RVs are pushers, I've never seen a class A motor home with a diesel up front, the van chassis ones would be exceptions but most of them have Powerstrokes or small Cummins.

    It's probably electrical, maybe the fuse making poor contact but more likely an injector, one injector shorted did that to one I drove. That one is hard to find unless you are looking for it, for some reason, it didn't throw a code. The check engine light didn't come on.
     
    25(2)+2, Jan 6, 2009
    25(2)+2, Jan 6, 2009
    #4
  7. Jan 6, 2009 #5
    Hibred

    Hibred Light Load Member

    64
    5
    Jan 10, 2008
    Canada
    0
    If its 470 hp it sure seems to be making very poor boost, our 12.7 series 60 in our Kenworth hits right up to 35psi boost when pulling, sounds electrical but could even be the turbo or as the poster above said an injector, check fuel and air filters, maybe some air getting in the fuel system somehow, might not hurt to get it on the laptop to look for any codes, best thing to do is take it into a shop with a dyno and they can diagnose it much easier when it acts up.
     
    Hibred, Jan 6, 2009
    Hibred, Jan 6, 2009
    #5
  8. Feb 4, 2009 #6
    DD14

    DD14 Light Load Member

    177
    32
    Jan 21, 2009
    Ontario
    0
    The low boost you have is definetly wrong,it should be in the 30psi. range.You might want to see if your TPS is sending the correct signal to the ECM.The jake situation you talked about..is it not coming on at all or are you saying that it is weak?
     
    DD14, Feb 4, 2009
    DD14, Feb 4, 2009
    #6
  9. Feb 5, 2009 #7
    dangerous dave

    dangerous dave Light Load Member

    127
    51
    Jul 20, 2008
    Houston, TX
    0
    My 60 had some issues last trip out. All kinds of crazy stuff. All intermitent. These computerized crap-pile motors are just like your puter at home. They live on good clean power. Loosen, clean, re-tighten all battery leads, leave grounds off for next step. Then move to starter, remove, clean and re-attach. Look for grounds running from engine and body to frame, remove, clean and re-attach. NOW re-attach grounds on batteries. Go give it a try. The poster above was also right about the boost. It should be higher. Check fuel lines for sucking air. You could also have weak spring on turbo dump gate. Good luck, God Speed.

    Dave
     
    dangerous dave, Feb 5, 2009
    dangerous dave, Feb 5, 2009
    #7
  10. Feb 5, 2009 #8
    lonestar382

    lonestar382 Bobtail Member

    3
    0
    Jan 5, 2009
    Prosper, TX
    0
    I have been suspecting the TPS. When this all occurs, it all occurs at the same time. The engine takes ages to build power, and the jake brake ceases to work. The tranny (its an Allison auto) will downshift normally, just no jake. I have also noticed a time or to that when this happens, it seems as the engine idle speed is slightly increased. This could explain the Jake brake since the TPS may not be sending a signal that the accelerator has been fully released. The system is designed to at first downshift the tranny, then enable the Jake, so if the TPS is showing a Very Light throttle pressure, it may still downshift, but not yet engage the brake.

    I will start troubleshooting all my boost hoses, clamps, intercooler, and turbo to try and find the culprit for the low boost.

    Thanks
     
    lonestar382, Feb 5, 2009
    lonestar382, Feb 5, 2009
    #8
  11. Feb 5, 2009 #9
    Truck Driver

    Truck Driver Medium Load Member

    330
    136
    Dec 5, 2007
    Sacramento, CA
    0
    You might also want to check the throttle sensor. I had a similar problem where the jake would quit and the power would cut in half.
     
    Truck Driver, Feb 5, 2009
    Truck Driver, Feb 5, 2009
    #9
  12. Feb 9, 2009 #10
    lonestar382

    lonestar382 Bobtail Member

    3
    0
    Jan 5, 2009
    Prosper, TX
    0
    Sorry about including my last name in the above posts. I apparently forgot that portion of the rules. Sorry for any inconvenience.

    Corey
     
    lonestar382, Feb 9, 2009
    lonestar382, Feb 9, 2009
    #10
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