3406 b sudden loss of power

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by tj379, Feb 3, 2022.

  1. tj379

    tj379 Light Load Member

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    Nov 10, 2019
    ontario
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    hello , i have a 7fb 3406 b that i lost power on yesterday, truck has allways worked really well, can only get bout 15 -19 psi boost but takes a bit, it used did junp to 32-35 psi when u got into it, i changed fuel filters and blew out fuel lines,checked air filters,checked turbo,turbo is 2 year old cat and spins n looks like new inside with zero play,, did a wuick visual of charge boots, all looked ok and never changed anything , inpuuled afr line no oil in it, injection pump was totally rebuilt 2 years ago also , lookin for ideas, to me whdn i stab the throttle its not gettin euff fuel, it used smoke black when i stood on it not now, everything else is normal, egts, fuel n oil pressure, ideling, no missing , ? stumped
     
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  3. Don379

    Don379 Heavy Load Member

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  4. tj379

    tj379 Light Load Member

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    Nov 10, 2019
    ontario
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    that is what im not sure of, i do not have a gage on truck and weather is gettin bad here to rigg one up at the moment, what i can say is truck idels fines reves up dont sputter under liad and the transfer pump thats on it is a cat one and was replaced about 3 years ago
     
  5. Don379

    Don379 Heavy Load Member

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    you in the middle of all that snow? rain out my way
     
    tj379 Thanks this.
  6. little cat 500

    little cat 500 Road Train Member

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  7. MACK E-6

    MACK E-6 Moderator Staff Member

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    @wore out would be our B model specialist. He’ll be along when he gets a chance.
     
    Catmando Thanks this.
  8. tj379

    tj379 Light Load Member

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    Nov 10, 2019
    ontario
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    i pulled the afr line didn't see oil in it, it was repkaced when injection pump rebuilt not sure the life on em?
     
  9. wore out

    wore out Numbered Classic

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    When it’s sudden like that AFRC diaphragm is the usual culprit. I had one not long ago that broke the nail head off the small spool inside, spool was froze in the piston.
     
  10. tj379

    tj379 Light Load Member

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    Nov 10, 2019
    ontario
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    thanks gonna have to pull it snd inspect thanks i will report back once completed
     
  11. tj379

    tj379 Light Load Member

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    Nov 10, 2019
    ontario
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    wore out , what or how is the best way of testing the afrc , removal and visuslly inspect, air pressure leak sosn , vacuum lesk down test?
     
    Oxbow Thanks this.
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