I'm trying to build an LED tachometer for my team's formula car, and I'm having trouble interfacing the tach with the car. I'm using a frequency to voltage converter to get a DC signal to my LED chip. I can't seem to get a good signal out of AUX 1 for the tach, though. Is anybody else having this problem? Does anybody have a solution for this problem? Thanks.

Where is Aux 1 coming from? What ECU are you using?

I'm using the AUX 1 port on the Motec 400/800 ECU.