
Hi Kirsty
It could well be the case that he hasn't as yet made the association fully that you are now expecting him to bark if he needs to go out - no offence, but it may just have been coincidence a few times and you have misread this as his signal that he needs to go ;) At 16 weeks or so he probably doesn't have sufficient bladder control as yet to hold on for any length of time so if you have missed more subtle signals by him of needing out he simply cannot hold on long enough. Additionally I've found that males in particular during cold weather need to wee a bit more often :)
>Some times he nos what hes doing because he will be weeing but runing away from me at the same time
It's unclear what you mean here

Is he running away as in (a) heading for the great outdoors or (b)appearing to be scared of you?
If it's the first option it is probably because he
is anxious not to soil indoors but simply can't hold on. If it is the latter, then perhaps you have chastised him verbally or physically for going indoors and so now he may be worried by your response and even holding on too long as he is worried about going when you're around.
HTH, regards Teri
Edited to add:
ps: at his age I would still be supervising ALL toilet trips and using a command word followed by praise when he's emptied himself :) While some pups pick up on things very quickly not all learn (or physically mature) at the same rate. Equally the owner can be too close to the situation to appreciate that they are perhaps being less attentive to house training than is still necessary to be.