Will's comments on mode of failure match my experience -- with old FPRs. But I have heard (here) of some new ones failing too, just not in my own experience. FPR problems are what led me to build a fuel pressure adapter for the Volvos within months of first owning a Volvo.

Without a pressure gauge, you can kinda get a handle on FPR operation by running the pumps engine off (with a jumper) and listening to the return flow toward the tank. With the motor off, ALL the fuel pumped returns to the tank via the FPR. When the motor is running, a tiny portion of that total flow is used in combustion, the rest runs back to the tank.


--
Art Benstein near Baltimore

Children in the back seats of cars cause accidents, but accidents in the back seats of cars cause children.