Originally Posted by jdodds
I happened to have an extra engine harness sitting next to me so I traced the wires out for you so there isnt any question as to where they go. Id bet that you have a stuck MFI relay. If replacing the relay doesnt work, PM me and Ill help you trace the problem.
The FSM pretty much says the same thing but makes it clearer what they are for.
Pins 5 and 6 are what the ECU uses to activate the fuel pump power (pin 5) and the MPI circuit power (pin 6). Like most things the ECU activates they are active low, the ECU pulls them to ground to turn them on. Since pin 6 is grounded that would cause the MPI power to be on all the time.
Usually this is one of three things. Someone blew the transistor that pulls ECU pin 38 to ground. The ECU isn't seeing the signal from the ignition switch that the car is in RUN or START position, or the backup power from the "room" circuit isn't reaching the ECU. I guess the wiring between the ECU and these things could also be suspect.
If ungrounding the pin causes the car not to start, the MPI relay isn't stuck.