Tach installed, works like crap.

[ike34]

I dont think it can be the ground, I have it hooked to an engine ground on the firewall.

 

[1SLO306]

check how much power you got going to the tach if there is not enough then it start to jump as the needle goes up. My autometer did it and i asume it will cause the same on urs

 

[ike34]

ok ill check that, what if i were to hook it up to the positive side of the coil what would happen? I also have the stock coil still, could it be causing anything?

 

[pistonhead351]

nope mine still does it, i grounded mine to the negative on the battery. only does it above 2000 rpm, if i go full throttle it seems pretty steady. I might look into an Msd tach filter.

 

[Mustang78]

why did you add another tach if your stocker works fine? you lost me....

 

[NKau]

why did you add another tach if your stocker works fine? you lost me....

Stockers are notoriously innacurate. Mine is close enough, and all I really need is a shift light.