which coil wires hook up to for tach

hello i have a 2002 hyundai accent and im going to run my tach to my coils. i hooked it up to one coil with the orange wire but its only reading like 1/3 of what it should. what other wire do i hook it up to on the other coil? thanks

jonathan

i would do the ecu but no one has been able to tell me where it is in my car as i dont know where it is, under the dash? whats it look like? i only have small black boxes that are 2 or 3 inches wide and long.. thanks

need more info is it a aftermaket tach if it is it should have a red power wire a black ground wire a white wire for the light on the tach and a green wire for for your tach wire on your car u can use your gray wire in your ecu which is under drivers side kick panel in should be a goldish or silver box with a big wire harness going in to it maybe two or three good luck