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Gordo2 Gordo2 is online now
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Join Date: Sep 2002
Location: Quantico
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Voltage on Black / Purple Tachometer Wire

Folks,

Tossing this out to the wider community of folks who have worked on 911 tachometers.

When I connect a multimeter to the black/purple wire that comes from my tachometer - I get a voltage reading of ~ 10v (key on, and the BLK/PPL wire only connected back to the vehicle tachometer / bare open ended wire - not connected to a RPM signal source).

I assumed that the BLK/PPL wire would receive a voltage signal from a source (CDI, dizzy, signal generator etc.) - as such I'm surprised to find the wire has voltage which appears to be coming from the vehicle's tachometer.

Anyone know if this is normal, or is something mixed up with my tach wiring?

Thanks, Gordo

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For background:

I'm troubleshooting a problem I'm having getting RPM to work correctly when connected to my vehicle tach and the LM-2 wideband meter. RPM Input to Innovate LM-2 from XDi Igntion
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Don "Gordo" Gordon
'83 911SC Targa
Old 08-01-2014, 11:52 AM
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