Wiring Diagram fuel control & injectors ref oil pressure sensor operation

[PaulRV6]

I need some help understanding how this circuit works. If the ECM controls the relay for the fuel pump by holding D&B terminals closed and closes contacts A&C above 4 psi oil pressure. If engine losses oil pressure and the switch opens the circuit how does that kill the fuel pump? Bc the ECM is still holding the relay closed. What am I missing in this circuit? Thanks

 

[pacecarta]

the oil switch when below 4psi isnt to kill the pump its for the idiot light, if it did the car could die while waiting at a stop sign in the summer if pressure dropped and thats not good for a car company to do to the customer
when above 4psi it supplies power so the relay doesnt have to carry it all and also power the pump before the ecu turns on relay for startup
most do a hotwire for pump and put an oil gauge where the sender was so the oil wire doesnt matter anymore

ecu doesnt hold D+B . the relay coil terminal A receives 12v from ecu when first powered (prime for 4 seconds ) and then turns back on after rpm signal is recieved other side of the coil is C is ground at back of passenger head
when coil is powered terminals D (12v in ) and B (12v out to pump ) make contact

the oil switch doesnt control the relay it sends 12v directly to the pump above 4psi

as for the diagram and explanation of how the fuel relay works you can look at steve woods site

Fuel Pump

 

[PaulRV6]

Perfect explanation thanks. Maybe you could help with this. Do I need the calpack chip in the ECM to give me serial data from the ALDL connector? I have a turbo link program I am trying to use to get some data from this engine and it won't connect to it. Thanks