Performance Issues

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by insanityeight, Feb 4, 2018.

  1. insanityeight

    insanityeight Light Load Member

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    Jul 26, 2013
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    I just purchased a 2014 paccar mx13 and had it unchoked and tuned to 530 hp and 1850 torque. The truck is geared high like 77 mph at 1600 rpms. But even after tune and unchoking it it is still pretty aweful on a 5% grade. The tuner guy says my turbo isnt big enough but ive read things to the contrary. Anyone have experience with one of these motors that actually does ok on hills. I thought having it unchoked would help a good bit but not really. Thanks in advance
     
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  3. pushbroom

    pushbroom Road Train Member

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    Before it was opened up, did it run good? If not you have underlying preformance issues that still need to be dealt with. Could be fault fuel pumps, air handling issues, ect. How much boost are you getting?
    Most guys that do the programming have no idea what power they are going to put it to. I always hear its never cranked up much over stock but you put it on the dyno and it lays 600 to the tires.
    That truck is geared pretty high. Not a stump pulling setup. How much weight are you pulling?
     
  4. spsauerland

    spsauerland Road Train Member

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    @ pushbroom is dead on. Tuning an "unhealthy" engine with not make it healthy. Turbo can support more power than your current settings. Most low power complaints I see with the MX without fueling issues is Air management issues. What boost is it making? Bobtailing and getting after it hard, you should be able to push 32lbs on 2013 MX-13 and hit higher #'s for a second on a stock 455 HP. Newer engines are all about trying to calculate the volume of the mass air flowing in and out of an engine. Need to make sure have no leaks from turbo compressor inlet to doc inlet. Paccar makes test plates for this. All air management sensors/tubes need to be verified to free of soot plugging. I usually just replace soot packed pressure sensors and clean the temp sensors. Wiping off is best, and if wanna use chemicals use carb cleaner not brake cleaner. Brake cleaner attracts soot. Have to pull intake manifold to check venturi tube orfices to EGR delta P , so will need new intake manifold gasket. Was EGR blocked off to intake with a plate, must be done with tuning? I will attach file of air management sensors. I would also run the overhead on it if it hasn't been done. Cruising RPM suggests gearing is pretty high and geared towards fuel mileage/low RPM's vs performance. Post last six and if KW or pete and we can tell you rear ratio.
     

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  5. insanityeight

    insanityeight Light Load Member

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    It will do average around 32 or so on boost and in really hard pull maybe closer to 36 or so but it was more of a dog before tuning so maybe its just geared to high. Idk
     
  6. insanityeight

    insanityeight Light Load Member

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    Vin 293239
     
  7. insanityeight

    insanityeight Light Load Member

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    Oh and last 2 tanks were 5.5 mpg or less so that has me flustered as well cos of the gearing
     
  8. insanityeight

    insanityeight Light Load Member

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    Guy said he programmed the egr plate to stay shut. No block plate and only drilled the dpf mufflers instead of hollowing them out
     
  9. pushbroom

    pushbroom Road Train Member

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    3.25 rear ends. RTLO18918b trans. 32-36 on boost sounds about normal. How much weight and what speed/rpm and you running at?
     
    Oxbow and spsauerland Thank this.
  10. insanityeight

    insanityeight Light Load Member

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    I usually stay at 40-45,000 but it climbs the hills with the rest of the fleet trucks
     
  11. steve092

    steve092 Light Load Member

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    I have a 13 pete 386 with a mx13... 455hp 18spd... I was pulling 40 to 45k lbs up hills and I dropped down from 105km/h to about 80km/hr.... Soon I will be grossing 120k lbs and I don't think that 455 will be enough...... Let's see tomorrow..
     
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