My girlfriends car

It may have a bad head gasket. Get a coolant system pressure test done.

You will need to test the fuel pressure at the rail to make sure there is adequate pressure there, then test to see if the injectors are pulsing with either a noid light or volt meter. The PCM controls the duration of the pulse and it should be consistent across all injectors. It sounds like you have done a lot of work to get this engine back going. Make sure all the sensors are connected. Also scanning your computer for engine trouble codes would be helpful. Your expert will continue to provide advice to get this figured out.

Here is an article on how the fuel injector works :
http://www.2carpros.com/articles/how-fuel-injection-systems-work

Just to add to this one lets start with checking the actual fuel pressure?ALso if the injectors are getting pluse signal see if auto zone has a noid light for rent I know they have fuel pressure gauiges for rent. Also cheking it for codes would be a good idea.

I agree that the fuel pressure should be of a high priority as well as injector actuation.
My one question to the customer would be, do you know where you lost the soolant from? What is apparrant like the radiator overflowed and/or resoreviour.
Is there any smoke coming out of the exhaust?
I think there is a good plan in place to solve this problem, so just hange in there and we will get you though it.

Takes Staurntech9s advice on all counts as he is a pro. There may be something to this injector pulse timeing.
Also have the trouble codes pulled at Advance auto or Auto zone while you are there.
You can also get a fuel test pressure guage thatre as I think that might be an issue.
Either ther pulse is off and raw fuel is getting blown out the exhaust or the fuel pressure is to high and getting forced past the injectors into the cylinder when it is not firiing causing the black smoke.
The more I go over this in my head I believe Saturntech9 may be right as it is doubtful the fuel pressure would go up high enough to create a leak by situation. It is proabbably a pulse timing problem.
So get the codes ppyulled and get the tests kits and come back to us with the results and we can glo from there.

There may be a possiblity that it is the cranskshaft position sensor and the ignition sensor.
If you pick up a code P0335 or the ignition failure sensor code P0320, it might be a problem that I was working on with another customer who never told me the outcome. The ignition sensor and the crankshaft psoition sensor both need replacement. It makes sense as it exhibits both ignition and fuel delivery issues.
I think this may very well be the answer. Let me know as soon as you get the trouble codes read and see if they come out the same.

It has spark so I doubt the crank sensor is a issue also sounds like from the intail post that it doesn't run so they can't get it scanned at the auto parts store. But code readers are so cheap these days. You can get a code reader on Amazon for about 20 and one that is more advance that reads some live data for about 50 something. Also if you watch eBay they have a lot of used professional scan tools like the Marco pro scans that are selling for just over a hundred. With older software that will still work on your car that will show you lots of data to help you fix your car. Let me know if you want some eBay listings. Also I would rent a compression tester and see what the compression is wouldn't hurt.