no rpm signal where to look

Okay i have a problem that i have been trying to figure out for awhile now. My car has no rpm signal so my injectors dont work. so i want to know what sensor does the ecu get the rpm signal from .

A good start would be telling us what car/engine you have…

1995 240sx with a ka24de

I think you get your rpm signal from the distributor on a 95 ka set up.Not 100%.