Well, lets play, why won't my engine start,...
It is a 6.1 in a 71 cuda with a Hotwire harness and computer

First let me start with a couple dumb mistakes I made, I hooked the fuel lines up wrong, and ran pressure to the return and now my regulator gauge is acting stupid, did I kill it??

After I switched them it still wouldnt start, but I pulled the line at the engine and it was under a lot of pressure, so at least it got fuel, not sure of the pressure....

I have a cheapo ignition switch hooked up, got it to crank over and pulled a coil, and had good spark...
Could the ignition switch cause the computer to not work?
right now, the computer is just sitting on the floor, should I mount it for grounding?

could the fuel presure not allow it to start, the engine has been sitting since 2007, and only has 2500 miles on it, could the injectors all be clogged?

seems I have fuel and spark???t

will it fire with a spry of ether?
I have had engines from the wreckers not start because the injector were stuck. A few taps with a screw driver got them working. Are the plugs wet with fuel?

Thanks Dave_S I will check that...

Ran into the same thing. What they don't tell you is there is no way to retain power to the computer when you crank. You need to hook up a push button starter switch to 12V hot and the start input to the Hotwire harness. It should fire right up.
To start turn the ignition switch to Run and then push the starter button.

This happened to me 2 years ago, it's possible they made some change to their harness.

This was in a 73 Chally, we hid the push button start in the headlamp/wiper switch bank. Drilled out the blank one and put a simple push button from Napa in there. It looked factory. I'll dig up a pic. We also put electric truck popper in the same switch bank.

Got it...It was the injectors, they were all clogged from sitting so long, cleaned them and it fired right up....

Thanks Everyone...

Congrats, get a video