I have bought 2 tachos from marlows each at $100 i bought one like 10 months ago and as i was rebuilding my car\engine i didnt know it was fkd till i started it, so i went there asked the dude
he says ohh they're very sensitive you have to hook them up right
bla bla bla, so i bought another one my brother hooked it up (hes a mechanic so he knows his shit) he hooked it all up right
so i started it up it gets a feed from it (the coil) but its jumping all over the show i dont think it is the slighetest bit accurate.
For you auto sparkies its hooked up to a constant power, earth, lights, and his hooked up to the coil. (4 wires)
should i cut my loses and get a new one (i'll be abusing the guys at marlows) any suggestions (3 1/4 inch tacho)