ok so i bought my 95 240sx and the tach doesnt work because he said they didnt connect a wire and he says its an s13 sr blacktop head with an s14 sr block.. i have ordered an autometer tach with the tach adaptor and when i connected it to the blue/red positive wire for the coil packs my car started to sputter bad. i even connected it to the cas wire and it did the same thing.. so im saying fuck that tach and i want to get my stock on working so if anyone knows how or have any input thanks.. oh and when i had the aftermarket tach on it says it was idling at 2000 rpm then it started to sputter