Hey guys so im getting in my car to test the wires going to the coil that used to be hooked up to the sun tach i had on my steering column. I test and found 1 positive 2 negative wires. So i try hooking them up to my factory mach 1 tach i put the positive on the red wire and the negative on the black and try to start the car the needle moves to 250 rpms while im cranking but it won't start, so i take positive wire off and start the car like normal then i hook the positive back up and the needle jumps to 900rpms and the car dies out. I can't have the tach hooked up without it killing the car. What should i do? Any help will be appreciated.