Just changed the injectors (from Greys to Blacks) and changed the chip and wired in closed loop and now the car wont start

Its getting a spark, and showing good fuel pressure on the gauge though?

Sounds like the injectors are 'clicking' (louder than usual), and turns over nicely.

Is it more likely to be the injectors or installation of the chip?

Can I quickly and safely try the old chip even though they are not for these injectors?

Any suggestions or anyone had similar?

thanks