Fuel Pressure Regulator by BWD/Intermotor (part#21849) / Fuel Injection Regulators

A:

I can suggest some possibilities. The fuel pressure regulator is actually a pressure LIMITER. It works ONLY when fuel pressure is too high (over 43 or 45 PSI),if pressure exceeds that rating, the regulator sends some gas back to the tank until pressure drops to the allowed pressure. Some possible causes for low fuel pressure are a weak Main Fuel Pump (located under the car near the driver's seat) a failing fuel injection main relay (corroded contacts), a clogged main fuel filter (located next to the Main fuel pump), and a bad Transfer Fuel Pump (located in the fuel tank). The engine CAN run with only the Main Pump working, but the Transfer Pump should be fixed if bad. Try cleaning the fuses (near the hood release handle) and their mounting contacts; bad connections here can severely limit the current available to the fuel pumps, reducing the pressure. Just doing this to my brother's 1993 240 DRASTICALLY improved the performance of the engine AND the power mirrors.