The clicking is the foregrip regulator recharging in bursts... it does that when you have a leak, don't ask me why.
The leak is usually caused by the LPR being too low or too high - there's a pretty fine range of adjustment. Turn the LPR out slowly until either the leak stops or the bolt moves forwards. If the bolt went forward, then turn it in slowly and the leak should stop when you get to the right point; turn it another 1/8 of a turn after that to be safe.
If you've still got a leak, the other cause I've had to fix a few times is a leak from the very short hose leading from the solenoid to the front of the ram, because it's quite a tight fit and sometimes it doesn't seal properly at one end. Find a bit of cocker hose (you only need about half an inch) and replace the stock short hose with that. Cocker hose is a slightly smaller bore so it seals to the barbs better.