New to tuning. Can a readable computer cause a car to not start?

[Chemacar]

I am working on a Jeep Grand Cherokee that doesn't fire to the spark plugs. Is there something in the computer that would cause that because all the wires seem fine? The computer seems fine/not broken since I can read it, and I didn't see anything in the file that would not cause the car to start. Am I missing something or is it just not the computer?

[LilSick]

of course there is

if you hold the pedal to the floor and hit go what happens to the spark?

[Chemacar]

The customer took the car, so I couldn't test that. Thank you for the reply though.