Ok all you trouble shooters. Tach issue

[SJW]

Installed an aftermarket Tach on my 4 cylinder. The needle jumps around as if it’s getting electrical noise. Ive cleaned the coil terminals and I’m the process of changing out the battery ground to engine. Are there any other things I should look at? Seems to bounce more at higher rpm.

Thanks In advance.

[Tik-Tok]

Wiring too close to another ignition component?

[SJW]

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Wiring too close to another ignition component?

I’ll reroute after I test the new batt ground

[firebane]

Make sure the tach is set to the proper cylinder setting if it has one.

[SJW]

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Make sure the tach is set to the proper cylinder setting if it has one.

It is

[mr2mike]

Might have to go shielded wiring for it if moving it isn't cleaning up the signal.

https://rspsupply.com/education/a-13...ed-wire-cable/

Unsure what gauge you need but I found headphone wire that was shielded to redo a knock sensor wire on a vehicle once that kept giving false knock issues.

[SJW]

The new ground wire may have done it. I’ll rip to work in the Sammy tomorrow. If not I’ll try rerouting and shielding this wire.

[SJW]

The grounding didnt work.

So far i've:

Cleaned contacts on coil
added new battery to engine ground.
installed a 10k ohm resistor on signal line.

Next up I'll try moving the signal line away from noise and try shielding.

Further I'll buy a new coil and throw this tach in the garbage and get something quality.

[Tik-Tok]

Try running the tach out of the engine bay as well. Straight line away from the coil, and power straight to battery. That'll narrow it down to the tach or coil as well.

[Flexray]

Cheapest and easiest shielding, twist the wires.

[SkiBum5.0]

Could be unrelated but I had a jumping tach when the speedo gear in my T56 magnum wasn’t the correct one.