Help ASAP. Car wont start.

[Erjay1]

So I pulled off the first two injectors just to check the size. Turns out they are Denso 550cc. I put them back in and the car ran like crap. Sounded like a Subby. So I pulled them off again and put new o-rings on them. Reinstalled them and now the car wont start. It turns over and cranks but nothing else happens. Where do I start looking. I made sure ever harness I unplugged was plugged back in and all vaccum lines are good. THis is a black top s14. Help, I need to get my car started.

Oh and before it started to crank over....when I turned the key the motor tried to turn over and it would make a loud clunk sound and stop. I'd try again and same thing. Just a clunk and nothing else. Wasnt until I let the car sit for a few minutes and tried cranking it again that it stopped making that clunk sound but it wont start. Just cranks and cranks but nothing.