1994 tachometer installation trouble

Just bought and installed a cheap tach for my truck. Everything is hooked up and wired in exept for the Green signal wire.

The instructions say that it is supposed to connect to the negative side of the coil. However, when the wire is attached, the truck will not start.

I pulled the boot back and had the truck running. When I touch the signal wire to the exposed coil wire, the truck stalls. So, I guess the tach pulls too much.

Am I doing something wrong here? Is the coil weak and in need of replacement?

Anyone here ever installed one on their truck?

Thanks!

If you truck is like mine it has an ignitor beside the coil. Connect green wire from tach to the solid black wire from the ignitor.

I ended up calling sunpro tech support. They said attatch the gree to the diagnostic serial port on the passenger side. I did and it works great. Pretty good looking wiring job if I do say so myself.

Same wire you could have just spliced into it at the ignitor and save yourself a little wiring!! But as long as your happy who else matters, except the old lady!!LOL