In the best case you should test for leaks without the setup mounted, but i usually cut my cable with the block mounted so it annoys me to remove them after (i'm too lazy )
The system just needed to be bled to work at best.
Is the gpu block inline with the cpu block? According to the pic it looks like it's yes. Is the cpu wb pelted also? What kind of temp are you getting on the cpu?
One last thing are you running it from the main psu or do you have a dedicated one for the pelt? What psu are you using?