Where is the fuel injector switch on 3406b cat engine

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Coolbreezin, Jan 14, 2022.

  1. Coolbreezin

    Coolbreezin Medium Load Member

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    Hey all. I have a '91 379LN. After the mechanic adjusted my clutch, the Jake stopped working. I told him that I wanted to fix the problem so I can learn. He told me to look at the fuel injector switch on the engine.
    From the clutch pedal to the engine cavity is all mechanical. I fail to see the relationship, but what do I know.
    So, any advice from my fellow "Logistical Engineers"?
     
    Oxbow Thanks this.
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  3. Last Call

    Last Call Road Train Member

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    There's a cut out switch on the clutch linkage for the jake brake also
    Since your clutch was just adjusted that clutch switch could very well be out of adjustment
    The throttle cut out switch is on the very back of the fuel pump its alittle black box with 2 wires going to it you adjust in or out to complete the circuit for your jake brake when the foot throttle is depressed.. it opens the contacts to break the circuit when you release the foot feed peddle
     
    Coolbreezin and Roger McG Thank this.
  4. rogermunn1

    rogermunn1 Light Load Member

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    If the clutch was adjusted and the switch on the pedal is out of adjustment now the clutch wasnt adjusted right . That would mean the pedal isnt coming back as far as it was before , sounds like the clutch wasnt adjusted at all only the linkage . It should have been adjusted under the tranny . Which shouldnt change the pedal position , only the free play
     
  5. Coolbreezin

    Coolbreezin Medium Load Member

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    Florida
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    Thank you for the info.
     
  6. Oxbow

    Oxbow Road Train Member

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    This is the throttle switch on mine. It also adjusts low idle rpm.
    PXL_20220109_170346086.MP.jpg

    It is on the back of the pump, low and near the block.

    Like others have mentioned it seems more likely that it is an issue with the clutch cut-out switch. I don't know on your truck, but look for a switch with a spring on it either in the cab on the clutch pedal or linkage, or on the clutch linkage under the cab.
     
    Coolbreezin and Last Call Thank this.
  7. AModelCat

    AModelCat Road Train Member

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    Clutch pedal position was changed when the clutch was adjusted. Either the adjustment was done incorrectly or it was previously incorrect and the mechanic set the linkage back to where it was supposed to be.
     
    wore out and Last Call Thank this.
  8. wore out

    wore out Numbered Classic

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    Exactly anytime something worked then didn’t immediately or shortly after working on the unit go back where you been
     
  9. rogermunn1

    rogermunn1 Light Load Member

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    NewBrunswick
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    I used to think this way too at one time. What i got was no no no your just a truck driver. you dont know what your talking about. And usually ended up worse off than before. The mechanics today arent what. they used to be. Thats why i pretty much take the day off and do it myself. At least its done right and i dont have to go back 3 or 4 times for the same thing
     
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