hi,
does anyone know how to count rpm with a arduino uno from a engine ?
i've been looking around for this a couple days and stil did not find how to do it propperly.
You're looking for schematic to connect to car wiring or sketch to measure rpm?
I've been looking for that as well a little time ago and got plenty of answers how to do that in 5 mins, then You must be doing something wrong..
yes, i am looking to connect wires from a motercycle but i think that it is kind of the same, I'm trying to make shift lights for the motercycle with a little program.
Where did you find the information to connect these wires? Where did you find you wiring setup and how to test it ?
Not sure what you need more.
"Engine" is way to generic and rpm are measured, not counted. "Oh look, an rpm. Oh, another one!" Na. 
Look for arduino shiftlight by Chippernut and You'll get everything You need.