my car was tuned on 760cc primary injectors and when i change back to the 550cc my car wont start....also i changed the 760cc to 550cc on the power fc data log n still wont start? NEED HELP

 

are you getting everything you need to start? air, fuel, spark? is it even cranking? need more info...

 

Yes, more info please. Check for the 4 big ones, then get back to us.

 

it crank and start but dies right away

 

Too much fuel for cold start is what was happening to mine. Turned out to be the thermosensor was not connected well enough so failsafed to a start setup for 80degrees c. Pushed the pin back in the connector and sweet as all fixed. Not saying this is your exact cause but worth checking

 

And jumper the fuel check connector. If that doesn't help then look for vacuum leaks. Also, make sure you have enough gas in the tank (it happens). Make sure the fuel filter is not clogged.