Does anyone know if the tach takes it's signal from the same source as the EDS. My tach does not work but the EDS does control the idle quite well, changing the position of the round plug in it's socket causes a change in the idle speed. If they run off the same signal then I know that it is in the tach itself. If not then this is a blind alley. And no the OVP fuse is not blown nor does substituting a known good OVP relay fix the problem. Cheers Dan

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Sounds like the problem is in the tach or the wiring to the tach. Set a voltmeter to VAC or duty cycle and see what signal you get from the tach wires as you rev the engine. FSM isn't clear what color the wire is but I'll guess green with yellow stripe.

You should be able to use any 124 Diesel tach. Gasser tach won't display rpm properly if at all.

Sixto
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