mustang not starting

I have a 2000 mustang gt that I bought. I have recently replaced the motor with one out of a 2002 gt. Swapped over my harnesses and now the new motor won't start. I can get it to turn over all day long but it won't fire up. It doesn't even sputter. I know I am getting spark. Anyone have any ideas as to why it is not starting up. Thanks.
 
Why did you need to swap the harness?

Is the computer throwing any codes?

Obviously, you need spark, timing and fuel, all in the right amounts. Since you are getting spark, that probably rules out a bad cam/crank sensor. You'd probably be best checking the fuel pressure.
 
Crack the throttle half way open. Does it start? Do you smell fuel?

What is the theft light doing? Is the battery strong and fully charged? Did you re-connect the motor ground strap?

If you place a noid light on a fuel injector, does it flash?

Do you hear the fuel pump run if the key is cycled on/off (do not crank)?

Can you monitor RPM's with an ODB2 scanner? No RPM's means no crank positon sensor equals no start. Not as likely as you stated there is a confirmed spark.

Disconnect the MAF sensor and try to start.
 
Ok Here is an answer to some of the questions. The harness had to be replaced because the 2002 engine wiring harness had the transmission harness plugged into it where as the 2000 does not. It was getting spark. But to be on the safe side I switched the good crank and cam sensor from the other motor over just to be sure. Still no luck. So I gave it a shot of ether and bam it fluttered and then I knew I had a fuel issue. Well I didn't think the injectors from the 2000 to 2002 would be different so I didn't think anything of it but I went ahead and swapped them over just to be sure and it fired right up. So thanks for the input everyone. Its amazing how something like that can create such a huge headache.
 
+1 on above.

This could have been a PATS issue. Remember that once the theft system is activated, the car will not start for 15 minutes. This means once activated, even if the correct key is used, it still will not start until the 15 minute timer expires.
 
I assure you for some reason it was the injectors. I can put the old ones back in and show you if anyone wants to drive to my house. The injectors in the new motor were pink top where as the injectors in the motor that was in the car was orange top. I don't know if there is a difference but that was the problem. The key was left in the ignition the entire time that this was going on with the battery hooked up. I was working on it for several days with the same results until I changed the injectors so I know it wasn't anti theft unless they have some new pita system that lasts 3 days or until you unhook all injectors and replace them:rlaugh:
 
The only thing I can think of that could have cause this and fixed when you changed the injectors is if you forget the fuel injector ground wire on the back bolt of the driverside and ended up hooking it up after the injector swap.
 
Fuel rail ground wire not it. Remember the fuel injectors are "ground controled". IE, the PCM completes the circuit to ground in order to fire each injector. So the injectors do not need a common ground to work.

The fuel rail ground wire is there to control static electricty that may be caused by flowing fuel.

The injectors are different as one is #19 and the other are #21's. However, electrically they should be the same.

Part of me still thinks there is something else going on here. Perhaps the fuel injectors were all bad from the donor motor. Did the motor sit in storage for a long time?

In any case, this just may have to be a mystery.