Pete 379 1995 Detroit S60 Tachometer

Discussion in 'Trucks [ Eighteen Wheelers ]' started by blairandgretchen, Feb 18, 2018.

  1. Diesel Dave

    Diesel Dave Last Few of the OUTLAWS

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    After all you been going thru.... I figure I will just leave mine alone. I shift by feel and sound of the engine anyways. Even with my stereo blasting (yes I have a concert sound), I could still feel the pedal. I surprised myself at times. ;)
     
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  3. blairandgretchen

    blairandgretchen Road Train Member

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    Just leave it alone - trust me!

    The scan gauge reads the RPM fine, must be getting signal from crank or cam sensor.

    Must be the wrong guage from Peterbilt, I’ve no other clues.
     
  4. pushbroom

    pushbroom Road Train Member

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    Scan gauge will read the signal from the ecm which will be cam/crank sensor.
    When the amtek instructions refer to an electronic engine, they are meaning when the tach signal comes from the engine ecu not an external sensor. Since yours is still wired to a speed sensor, the dip switches must be set like doing the math of flywheel teeth like you have posted earlier. I know the ohm reading is the same top and bottom, but one of the wires could be shorted to ground or only hanging on by a thread. Since it is just 2 wires twist up a new pair with a drill and run them down to the sensor. More then likely the wiring is compromised but not enough to show up with an ohm meter.
     
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  5. blairandgretchen

    blairandgretchen Road Train Member

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    Is there a reason for the twist? I think there’s a set of wires to the ECM twisted the same too.

    Either way, I’ll try that tomorrow - without even running them through the loom - see what happens.

    Thanks!!
     
    Oxbow Thanks this.
  6. pushbroom

    pushbroom Road Train Member

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    The twist is to stop electrical interference. Any speed signal on a truck is twisted along with data links which are shielded as well.
     
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  7. Oxbow

    Oxbow Road Train Member

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    I didn't know that, thanks!
     
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  8. blairandgretchen

    blairandgretchen Road Train Member

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    Also one set from the ECM is twisted also, for the same reason. Learned that the other day too.
     
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  9. blairandgretchen

    blairandgretchen Road Train Member

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    PROBLEM SOLVED

    @Old Man sent me a used tach out of a carcass he bought - plugged it in, works fine.

    So, original one is dicky.
    New one from Peterbilt is either wrong one or defective.
    Used one works.

    Now, to see if I can get a refund out of Peterbilt . . .
     
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  10. blairandgretchen

    blairandgretchen Road Train Member

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    Peterbilt took the tach back and refunded the $208.
     
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  11. haycarter

    haycarter Road Train Member

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    [​IMG]
     
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