An automotive paint system using mass flow controllers (MFCs) for closed loop control of the shaping air was experiencing unusual problems. For proper control of paint quality, it is necessary to have a consistent volume of clean dry air at the spray head. Fortunately, the Alicat Scientific MFC is a multi-parameter device that includes not only mass flow but volumetric flow, temperature and absolute pressure information. Using the MFC’s digital interface the user was able to log the output of all the MFCs in the process over time and thus discover significant fluctuations in temperature. This made it easy to track down the source of the problem which turned out to be a faulty intake manifold bringing in unconditioned outside air. Earlier the same company was able to determine an airline leak before a paint line upset by noticing a drop in pressure at the MFC.