Derating on SDP single turbo conversion

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by J.N.W, Oct 9, 2021.

  1. J.N.W

    J.N.W Bobtail Member

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    Oct 9, 2021
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    I bought a truck that had an SPD Cat (don't know the year model) with a 6nz single turbo conversion. Overhauled 115,000 miles ago. Had it derating me, smoking blue, and just overall powerless. Brought it to a mechanic/tuner who put a new delete program in it, and replaced 2 injectors. Worked good for two weeks after that, and now it's back to powerless, derating but no blue smoke. And it comes and goes but can always rely on it to fail when pulling something. One of the many strange experiences I had with it this week was, I was headed to a place to pick up a trailer, started shaking and derated me, so I turned around headed back to the shop, worked great heading back. Have that happen more than once.
     
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  3. rydr

    rydr Light Load Member

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    Jan 8, 2019
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    my sdp did sorta the same thing. would shake really bad and not boost over 20psi when i would step on it, empty or loaded. with the twins and a single turbo it did the same thing. never figured it out as it sits on a pallet now :) its probably a vva/iva issue - i always thought mine was! good luck
     
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  4. Magoo1968

    Magoo1968 Road Train Member

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    If it was rebuilt as a 6nz maybe hang a 6nz ecm for a test drive.
     
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  5. J.N.W

    J.N.W Bobtail Member

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    Oct 9, 2021
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    Did yours do that all the time? Or work fine sometimes and fail other times?
     
  6. rydr

    rydr Light Load Member

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    Jan 8, 2019
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    Bought the truck, it had been deleted by previous owner he kept the twins on it. It didnt do it on the way home, but once i got it under a load it started and got worse over time. Rebuilt it with ipd low comp pistons and went with a single turbo then got the ecm re-tuned. Worked great for a week or so then the problem started again and got worse over time once again. Got tired of it so I swapped a 3406 into it.
     
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