2012 500hp ISX With Low Power

Discussion in 'Trucks [ Eighteen Wheelers ]' started by charliev, May 16, 2012.

  1. charliev

    charliev Bobtail Member

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    Hey guys,

    I've got a 2012 Cummins ISX 500/1850 in a T660 that can't get out of its own way. It's got an 18spd with 3.36 gears and low-pro 24.5's with 74,000 miles on it. It will, depending on the gear and speed, blow 37-38lbs of turbo boost. I've had it in to the dealer, they did a software upgrade to the ECM and turned off the "driver rewards" and "progressive shifting" settings among other things to try and get it to pull better, but it's no where near what it should be. The benchmark by which I'm measuring it is my 2009 Cummins ISX 485/1850 also in a T660 with the same drivetrain. The 2012 won't even come close to keeping up with the 2009 in the hills.

    When I ordered the truck I was under the impression that it would be "up-rate-able" to 565 with just a visit to the dealer's computer (and more $), but I found out it would actually need mechanical upgrades to give it more power. When I first bought the truck they told me to wait until 35,000 miles and it would break in, but now with twice that, I'm still not thinking it's pulling well enough.

    Fuel filters aren't the issue. There seems to be no difference in power with 2 units of restriction or 8 units (the most we've let it get up to prior to changing the filters out).

    Has anyone had a similar problem and resolved it? Thanks in advance
     
  2. fortycalglock

    fortycalglock Road Train Member

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    Did you have 3.36 rears in the other truck?
    If so, what's the dyno say?
     
  3. charliev

    charliev Bobtail Member

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    They're geared the same. We haven't had it Dyno'd yet. I don't think the KW dealer has a dyno and Cummins NE has absolutely the worst service-writer/shop manager I've ever done business with. That's going to be the next step. It's just a pain in the butt laying the truck up and taking the time to get it dyno'd.
     
  4. MNdriver

    MNdriver Road Train Member

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    so you are relying on the denim dyno to tell you it's not pulling right?

    With an actual baseline, it's hard to say where you are at.

    Sure something isn't de-rating the engine on you?
     
  5. charliev

    charliev Bobtail Member

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    Would I, as the driver, be the denim dyno?

    If the engine were de-rating, it would do so for a reason and log codes of some sort. Plus, I would imagine, the check engine light would come on if there wer problems which led to a de-rate.
     
  6. MNdriver

    MNdriver Road Train Member

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    denim dyno = seat of the pants....;)

    I would think so. Just a thought is all.
     
  7. blanco

    blanco Road Train Member

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    what kind of fuel mileage are you getting??
     
  8. power freak

    power freak Light Load Member

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    We have the new ISX rated at 550 in 2012 kw and our 09 525 ISX will walk all over them. It's just the way they are.
     
  9. Hardlyevr

    Hardlyevr Road Train Member

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    I don't know about other brands, but in my Volvo you can find diagnostic fault codes in the list, without ever seeing and idiot light come on.
     
  10. charliev

    charliev Bobtail Member

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    I like the term denim dyno!

    Sorry, I just read my response and it sounded way sterner than I'd intended.

    "What kind of fuel mileage are you getting??" = 5.7-7.4, Depending on which trailer I'm pulling, but we never really gross over 65k.

    "We have the new ISX rated at 550 in 2012 kw and our 09 525 ISX will walk all over them. It's just the way they are." -It figures, every time they make emissions tougher the same engine HP rating seems like less and less.

    The other day I followed my two other trucks for the length of the Mass Pike out to NY and I could barely keep up with them and they never went over 72mph. We were all empty...
     
    MNdriver Thanks this.
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