Hi, I've got to install a CDS Co Pilot 2 with the newer Serial Sensor Interface box. I'm missing one part, and I'm hoping for someone who either has a tach sensor or knows of a substitute! This would be the 5V "SEN 17E Electromotive Ignition Sensor" on the CDS website, not the older magnetic pickup. I've seen a few possibilities for a substitute, but it looks like most put out a 12V signal. I use Petronix, in case that makes a difference. Any ideas?