internal timer question

Hello there. I've made a program that calculate the rpm and the advance on an engine. However, because of high rpm, advance calculation is not precise. I used micros() but i decided to switch to internal timers, interrupts, etc. I have an interrupt every time a digital pin rises and the second interrupt when the second pin rises. I want on the first interrupt to start a timer (with or without prescale) and when the second interrupt triggers, count how many clock cycles passed. I used ICR1, TIMER1_CAPT_vect but with no luck. Some ideas please?

Can you show the code maybe?

Which pin were you trying to use for the timer capture? It only works with one specific pin.

Please see section 16 of the Holy Data Sheet.