Abstract: An internal combustion engine diagnostic sensor system comprises a fuel rail for the engine wherein the fuel rail has a high pressure inlet end, a plurality of injector ports, and a terminating end and wherein a piezoelectric sensor is mounted on the terminating end. The piezoelectric sensor is in open communication with contents in the fuel rail. In addition, the internal combustion engine diagnostic sensor system comprises a fuel rail for the engine wherein the fuel rail has a high pressure inlet end, a plurality of injector ports and a terminating end. There is also a connecting means disposed at the high pressure inlet end of the fuel rail wherein the connecting means has a near end that is openly connected to the fuel rail, and a distal end that has mounted thereon, a valve. There is surmounted on the valve, a piezoelectric sensor, wherein the piezoelectric sensor is in open communication with the contents of the fuel rail through the valve.

Abstract: Piezoelectric transducer assemblies that are useful for the monitoring of the gas output from a gas driven pump, wherein the assembly is not an integral part of the input or output flow stream of the material being pumped, but is used to monitor the exhaust gas flow of the gas driven pump.