Swapped in 5.0 wont' start

[Kevin Price]

I assume you are putting starter fluid directly into the cylinders via the spark plug hole. Given this, the spark from the plugs is igniting the starter fluid. However, since your computer is not telling your injectors to "squirt fuel" it will run just long enough to burn the starter fluid.

Also, should you need the relay you can call Mustang Parts Specialties in Winder, Georgia. They'll have what you need. Let us know how it goes.