How long do you grill a 4 pound pork tenderloin?

A 4lb pork tenderloin? Are you sure it comes from a Pig??!!. If you meen striploin then 1.8kg is big lump of meat to grill and would be more suited to roasting. But if its grilling you want then dry marinate 8oz/220g steak slices and go from there.You should get 8 fat steak from this.