Bosch fuel pressure regulator disassembled with labeled componen…

Ths failed Fuel Pressure Regulator (FPR) was diagnosed simply by pulling its red vacuum line off, then cycling the key to RUN a few times. If liquid gasoline comes out of the FPR, its diaphragms have ruptured, which will either flood the engine (if you're lucky) or slowly make it run so rich that it washes the rings out (if you're NOT). It can also be diagnosed by disconnecting the vacuum line while the engine is idling, but that risks dumping gas onto a running engine, which can start a fire, so DON'T.

.

Owner caption January 2020 · Photo 20 of 121