Tach signal on self starters?

So..  The vehicles that self start-- you know the ones that you merely pulse the start position and it continues to crank until engine starts (examples I can recall are the new Grand Prixs-   2004+ and the trailblazers) I assume no one wires a tach sensor to these- since the starter wire only needs to be pulsed. also there is a model that doesn't even have a starter wire in that it senses when ignition is on and accesorie is off as an input for the BCM to activate the starter-- I assume no tach signak is needed here as well.  Any thoughts?Brcidd - Engineer That Does Remote Starter Installs on the side.

     You would still need a tach or a coil to do the remote start or the starter would not disengage.

Only if you install those brands that don't use voltage reference, or are NOT  able to program in variable starter engagement times such as .5 or .75 sec is the way I see it..Brcidd - Engineer That Does Remote Starter Installs on the side.