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  1. 94-98 Non-Powertrain
    i have a 2008 ford f350 with a 12 valve cummins. when i start the engine the tachometer either doesn't move at all or is jumping all over the place, but if i start the engine and simultaneously press on the gas pedal then the tachometer works fine. How do i fix this? I already replaced the whole...
  2. 89-93 Non-Powertrain
    Working on my 91.5 w250. Can anyone post some pictures of the connections to their factory/dealer installed tachometer on 91.5 and back trucks? Thanks
  3. tach-amp


    This is the tachometer drive circuit and amplifier I built to replace the PCM drive circuit. This circuit provides output similar to the backlash in an ignition coil that gives a strong zero crossing signal the tach uses as timing pulses. Have fun!