Power problems

Discussion in 'Trucks [ Eighteen Wheelers ]' started by spudman76, Apr 16, 2017.

  1. spudman76

    spudman76 Bobtail Member

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    Apr 16, 2017
    Idaho
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    i just recently had the front structure, new head, new air to air, done on my 6NZ cat. After the mechanic put it all back together and we fired it it seemed to be running ok. But I thought that it had a miss to it. Come to find out check engine light came on.... the cam was off one tooth. It got set right and timed the engine again. Replaced the crank shaft positioning sensor and went back thru the overhead. Engine sounded and ran much much better. Now the problem is.... anytime that I'm getting ready to go into a hard pull, there is no power and I have to shift down several times just to keep the truck wanting to climb. I can hear my turbo spolling up but almost like it's not spolling all the way. It's almost like driving a diesel motor with no turbo at all.

    Does anyone have any suggestions of what it can be? Keep in mind that the motor ran great before we did all of that. Just needed to fix a lot of oil leaks and head ended up not being good.
     
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  3. Tug Toy

    Tug Toy Road Train Member

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    I'd be checking the CAC. If it was removed to do the work it could of got cracked. Do you have a boost guage? With leaky boost it sounds and runs fine till you actually need power. Then nothing.
     
    SAR Thanks this.
  4. x1Heavy

    x1Heavy Road Train Member

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    Mar 5, 2016
    White County, Arkansas
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    I will go along with Tug Toy's idea. Compression plus boost air = power.

    Take a look one more time at all clamps and such similar devices that secure and connet every hose large and small that transfer air towards your engine and turbo. Something like a mr bubbles toy kit with a small gauge bubble maker will detect small leaks well enough. Even if it is smeared on. Just don't get that bottle anywhere on hot surfaces. Im been away too long to remember the effects of heat vs something of that basal in nature.
     
  5. spudman76

    spudman76 Bobtail Member

    18
    4
    Apr 16, 2017
    Idaho
    0
    I do have a boost gauge... come to find out it doesn't work. I'm replacing it tomorrow. And forgive me.... what would the CAC be? Also I did plan on going thru all the clamps and hoses tomorrow. I don't believe that it's anything internal. No check engine light. Also... my turbo was replaced a year and a half ago. So I didn't think that was the problem either.

    Now here another thing... the gasket on my air compressor is going out. So it's got a pretty good tick sound to it. Could that also add to my problem? I'm also going to replace that tomorrow.
     
  6. SAR

    SAR Road Train Member

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    CAC= charged air cooler. I second checking for boost leaks. Do you have a pyrometer by any chance to monitor exhaust gases? If your getting a boost leak that will elevate higher then normal readings
     
  7. SAR

    SAR Road Train Member

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    Nov 26, 2011
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    I just recently checked for boost leaks on my CAT and another member here suggested using a bottle of windex. Idle up your engine to about 1500 rpm and spray all your connections and look for bubbles. I had three spots that bubbled up on mine which surprised me.
     
  8. spudman76

    spudman76 Bobtail Member

    18
    4
    Apr 16, 2017
    Idaho
    0
    Ah ok. My CAC is brand new. Had to replace it too. My old one was cracked and wouldn't hold pressure. So I sure hope that isn't the problem. But I will check it out too.
     
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