I've tried to rebuilt the metering head and while measuring/adjusting the fuel level between the injectors, one of the injectors has fuel coming out of it before I lift the flap up, is this a problem with the metering head or elsewhere? Also I dont think it was doing this before I rebuilt the metering head Thanks
swap the affected injector with one of the others, see if the problem moves with it or remains on that cylinder
This can also happen if the CO adjustment screw (hole between air flap and metering head) is screwed in way too much. Causing the piston to open the passage to the fuel injectors even before the air flap is lifted. The injector opening is possibly the one with the lowest opening pressure (they are not perfectly equal as you know).