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SDS with stock 1973 240z tach

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You have 3 options use the later tach. There is a mini circuit board option if you google you will find it .


from classiczcars


The 4 wire tach 240Z tach uses a current sensing circuit on the positive side of the coil. With the original points type distributor the +12V (black wire) connected to the ballast resistor. The green/white wire runs from the other side of the ballast resistor to the tach. The black/white wire returns from the tach to the positive side of the coil.

To get the tach to work you need to connect the solid black wire to the green/white wire (remove the black wire from the coil) and connect the black.white wire to the coil.


I wish I knew this before I went with aftermarket gauges. From what I understand and seen here on HBZ guys with MS2 and EDIS which essentially the same type of coil pack. You bypass the ballast resistor run the tach from the 3 terminals of coil pack with diodes I believe straight to tach.

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