1992 RS - Swapped in carbed 350. Removed ECM and all sensors except coolant sensor for guage and oil pressure sending unit. Using in-tank stock fuel pump with return-style regulator. When I connect battery, fuel pump runs constantly, whether key on or off.

How do I get proper fuel pump operation with ECM removed?

 

...one of my friends who did a V6 to V8 swap used a switch in the car to turn on the FP....


350Z

 

That would be the simplest route, wire in a new circuit solely for the fuel pump.

wire from ign hot source with a fuse to a toggle switch. From the toggle switch into a relay then from realy to the fuel pump. For added safety you could wire in a low oil pressure safety switch that will kill power to the fuel pump if oil psi gets below a certain point should the motor take a crap on you or if you get into a wreck.

 

Problem found! Oil pressure sending unit bad - giving positive pressure reading always, enabling fuel pump always. Weird that the relay doesn't do anything - I unplugged relay and fuel pump still ran - until I put new OPSU in. Looked at schematics - fuel pump gets a hot always feed directly from battery through OPSU.

This would also explain the dead battery after 2-3 days of not running the car - fuel pump always on draining battery. Can't hear the in-tank pump in the street, with traffic, neighbors lawn mower, dogs barking, and various other daily noises one faces in the driveway. So, if anyone ever has a battery always dead after 2-3 days, check fuel pump for noise with ignition off in a quiet spot. Lesson learned - ALWAYS have a house with a quiet garage!