Speedometer Help

A little back story of why I need some help.
I recently dropped in a new motor in the car. 351w along with that motor I replaced the ignition with an msd 6A. I have the accel super coil as well. Shortly after installing all of that my Autometer electronic speedometer started acting up. Would just peg straight up all the time. Not light up at times. Well finally I took it out and connected it straight to positive and negative. Well that's when it finally decided to die out. Cause not I get absolute nothing on it. So I'm guessing its died out. Well I'm looking at purchasing a new. So far I have found the sunpro CP7215 which is another digital speedo. Well what I need to know is what else will I need for this to work. Do I need a speed sensor or not? I have no idea if the car had one previously cause I didnt wire it up. Can anyone help me out and give me a little input on this. Sunpro has been little to no help on this with me.
Thanks all for any help
Aaron

 

If your set on using a electric speedometer you will need a speed sensor. What trans are you running? If it has a mechanical speedometer drive then it probably all ready has a gear driven speed sensor on it that ran the old electric speedometer. If the speed sensor has 3 wires it is a hall effect sender, if it only has 2 wires then it is a pulse generator. You can work backwards from there an get the proper speedometer to mach your speed sensor or go with a company that uses a spedometer that will accept either speed sensor. (Like New Vintage Gauge) Or if you have a trans that drives the speedometer mechanically go old school and get a cable driven speedometer.

 

I had an Autometer tach go bad. I returned it to Autometer and the cost to repair it was very resonable. If I remember correctly it was around $30.

 

You have to make sure that the speed sensor wires are sheilded form anything electrical that will interfere with the signal from the speed sensor, like high energy ignition coils.

 

I have a ford c-4 transmission I believe out of a 92 mustang. The old speedometer was an electronic that's why I was gonna stick with the same. It has 4 wires coming out of it. red white green and black. I guess Im confused on where the cable that actually tells the speedometer the speed where it goes.
Thanks
Aaron