In this paper a statistical based methodology to work over the principal component space on injection moulds is presented. The Multiway Principal Component Analysis is applied as a dimensionality reduction step, and fault detection assessment. This methodology allowed to analyse the behaviour of injections with the information directly received from sensors, what ended in a better process understanding. Results concluded that with a low number of variables (some principal components and two control statistics) is enough to detect abnormalities (too short injections, injections with low variability, etc.).