Can the coiled water temperature sensor wire cause interference to the tach signal wire? After I installed the gauges I started having issues with my tach. The tach worked fine before I did the gauges. With the car running tach runs fine if the ground is disconnected, connect the ground and it sits at zero. When tach is working without the ground connected you turn on the lights the tach goes to zero. Turn the lights off and it works. There are other wires near the signal wire from the gauge install so not sure which is causing issue. Can you shield the tach wire with rubber hose to protect from interference? I havent dug into this yet so asking ahead of time.

 

No.

Starting with the fact that the water temp capillary tube is grounded, and ground wires can't do that, but even if it wasn't grounded, still No.

How is your engine ground strap?

- Eric

 

Thanks Eric. I wasn't sure but thought it wouldn't cause an issue. The tach worked fine after I installed it before I installed the gauges. Will remove the gauge wires one by one to find problem wire.