Tach Pegged Out

[jigoe007]

New Vintage tachometer will not reset with power or without power. The tach worked during the initial startup of the car but now it remains pegged out at 8,000 rpm. The tach has 12.56 volts to it with the ignition key on and the engine is off. When the car is running the tach signal wire shows around 3 volts and it does not vary much when i increase engine speed. Engine is a carb LS3 (LS376 / 515).



Per the New Vintage manual I installed a 10K ohm 1/4 watt resister between the tach signal wire and switch 12 volt power but still the tach does not work. The fuel level gauge and voltmeter work fine which are located in the same unit as the tach.

[andrewb70]

New Vintage tachometer will not reset with power or without power. The tach worked during the initial startup of the car but now it remains pegged out at 8,000 rpm. The tach has 12.56 volts to it with the ignition key on and the engine is off. When the car is running the tach signal wire shows around 3 volts and it does not vary much when i increase engine speed. Engine is a carb LS3 (LS376 / 515).

Per the New Vintage manual I installed a 10K ohm 1/4 watt resister between the tach signal wire and switch 12 volt power but still the tach does not work. The fuel level gauge and voltmeter work fine which are located in the same unit as the tach.

Where is the signal coming from into the tach? Is it from the spark controller? If that is the case, you do not need the pull-up resister.

Andrew