This can relate to either a mechanical or tooling problem. To determine which it is, examine several of the sprues you pushed out. If the sprue has about 2-3mm (1/8 inches) of straight shank that appears to have been frozen and then pulled out of the nozzle, you probably have a mechanical problem in your IMA system. The assembly is not being held tight enough as it rotates to shear the sprue, or in the case of a Horizontal Cable system, the locating ring in the tooling may be worn. If you are certain the sprue is shearing properly, but the sprue still stays in the fixed tool and has a substantial tail on it, you have a tooling problem. The cavity end of the fixed tool sprue hole could be chipped or damaged, or the sprue hole could have zinc fused to the tapered surface and be in need of cleaning. In either of these cases, a visit from a FisherTech Service Technician to evaluate your system could save you frustration, time and money. If there is no tail on the sprue, it is likely a timer or a temperature problem. Check the coolant system in the tool, lower the torch flame, or increase the injection time a little to allow the zinc alloy to freeze further into the nozzle.