I have a 92 RS with TBI converted to carb. I am still using the in tank fuel pump with a return style regulator to supply the correct fuel pressure for the carb. I had planned on leaving the computer in to provide the initial couple seconds of fuel pump prime before start, and relying on the oil pressure switch to provide the constant power to the relay while the engine is running. Everything was working fine until last weekend, when it appeared that the pressure sensor had gone bad. I swapped it out (Really AutoZone $50????), which appeared to fix the problem for about a 10 minute drive around my neighborhood, after which I had the same symptoms. My only guess at this point is that the high pressure oil pump in my new engine is blowing the sensor out? Anyone have any suggestions on a better solution, or a replacement part that could handle the higher pressure? I know I could just wire up a switch to the relay, but I was hoping to avoid that if I could. I wanted to maintain the safety of the fuel pump shutting down with the engine, in case of an accident.

 

Are you sure its the oil switch that's broken and not something else? Maybe faulty wiring or bad pump? The fact that it was previously running with this setup makes me think its not the pressure. Also, I don't think the pressure could get high enough to actually break the switch, but I could be wrong.