hey gang, my fuel pump control circuit went dead. the ecm is not sending the voltage to the relay. i need to know the logic flow for the ecm. i need to know what tells the ecm to turn voltage on to the relay. thanks

 

At key-on, engine-off the ECM enables the FP relay for 2 seconds. Then at crank or run time the ECM enables the FP relay whenever dristributor reference pulses (DRP's) are present. Two seconds after the last DRP the ECM will disable the FP relay (such as when the engine stalls).

There is also an oil pressure bypass switch that enables the fuel pump whenever oil pressure is above ca 4 psi. This switch doesn't use the relay, it powers the pump directly.

RBob.