wiring up rev counter

[Lang Inder]

In the 140j i have a 160jsss dash cluster with the rev counter etc, but am having troubles getting it going, the rev counter has two wires comming out the back of it and i ran wires from these straight to the coil, but it just creates a short and cuts the spark? switch the wires around and it does the same thing. any ideas?

[Bartman]

I'm pretty sure datsun Tacho's run an "inductive loop" type set up.

[Lang Inder]

please explain?

[Bartman]

ONe of the wires on your coil (I can't remember which) passes by your tacho. And the two wires on the tach loop through it. (In series) Then something inside the tacho reads the pulses through the wire and measures the rpms that way. And if that wire is unplugged, the car wont run. Odds are your loom wont include that loop.
I don't fully understand how it works, only what it does.
I know this can be a real problem with fitting a Modern muilti coil engine, as the tacho isn't configured to work with one of those installs.

[datsunboy]

If it's an inductive one, then those 2 wires will just power and earth. The loop will go thru a little plastic block on the back

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[datsunboy]

and it's the positive wire from the ignition go the coil that goes thru it

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[mint16]

Tachos run off negative side of the coil and battery earth.

[datsunboy]

Depends which sort if taco. A 3 wire aftermarket taco will run from neg side. But a stock Datsun one will most likely be the inductive you're running on the positive side

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