Not exactly, my buddy has a S-10 show truck and he was in town and I was sitting in his truck at a party, he had his truck i guess you could say "sponsering" the party music. His Ipod was hooked up to it on random with about 2800 songs. Loud *** Bostons and MB Quarts setup.
Anyway, i was chilling with him and saw this 1000 or so kinda fluttering on the screen, so i asked him what it was. He said to push the gas, so I did and it went up right along with the tachometer.
It is a tach, not a voltage meter. He said he set it up by reving his engine up to 2000rpms and setting it. Then it just worked from there. It was cool as shit.