The “Speed Relay” comes in a few versions for early Porsche depending on whether the car had Carburetors (911T and certain 912 models) or MFI (911 E,S). This device is found on the engine electric panel. It monitors engine speed and on closed/trailing throttle situations it cuts off the fuel supply until the rpms drop under approximately 1700. This conserves fuel, improves emissions and serves to reduce exhaust “popping”. The most common problem with these units is component failures due to vibration and corrosion resulting in mechanical failure of the component leads. It is not uncommon to shake these units and actually hear parts rattling around loose inside!
Service consists of disassembly, cleaning, bead-blast, re-label of housing and repair and testing. Send your unit in for service and it will come back to you looking and working as new again!