Tach Noise When Pushing the Clutch?

Discussion in 'Engine Topic' started by redriderjf87, May 7, 2018.

  1. redriderjf87

    redriderjf87 Veteran Member

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    I am doing some researching on wiring and looking under the dash, but this one kind of has me stumped.

    Basically the tach seems to read and respond ok if I'm idling or driving normally, until I push in or release the clutch, at which point the signal drops to 0 and jumps for a second, then comes right back as if there was no issue. Pretty much happens every time (or close to) I clutch in or out. Doesn't matter how long I leave the clutch pressed in or how fast/slow I press it. Of course this throws off the FiTech which thinks the engine died and shuts off gas for a split second :(

    If I do this with just Ign power on and engine not running, it will show the tach at 0 like normal and then jump up between 200-500 rpm for a split second. My MSD Pro Billet has 2 tach leads and they both show consistently between my gauge and the EFI readout.


    Things I have tried to clear up noise to this point:

    Switched my IGN power source to the HEI (replaced factory 12g wire with a 10g wire run from the IGN fuse.

    Ran a separate ground directly from the battery to my HEI ground wire

    Covered my tach lead wires with grounded shielding and ensured they are not within a few inches of my plug wires, nor touching the block.

    Tried unplugging the gauge tach lead, EFI tach lead responds the same.




    Someone please tell me what simple thing I am missing. I am hoping it's something with my neutral safety switch wire or something like that, but to be honest I'm not even sure how that would make a difference. Sorry for writing War and Peace if you made it this far.
     
  2. redriderjf87

    redriderjf87 Veteran Member

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    Ok false alarm, for anyone curious or who may have the same issue in the future, my clutch pedal at full travel was just barely pushing against the HEI power wire coming out of the fuse block and must have been not allowing full connection... Re-routed it more properly, so far so good.

    If nobody ever has this problem, I hope this at least entertained someone!
     

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