General ECU Power wiring

[dsmtalon2008]

Well, here is the deal, I basically stripped my car of almost all wires minus the ones that are a necessity for the motor to run. Included in this removal was the stock starter solenoid (aka I have push button start now), fuel pump wiring (running inline bosch 044 with my own wiring). I can get the motor to crank via the push button and the fuel pump to pump and recirculate with 43.5 psi fuel pressure.

Now when I put the key in the car the check engine light should come on correct? It does not. Therefore the injectors/coil pack is not going to work (duh).

Now for my question... how am I going to get the ecu power without using the mpi/mfi relay since the relay will never let the ecu get power since it is not seeing there is an actual fuel pump to give power to? (hope I understood how this works correctly)... Any help would be GREATLY appreciated!

Thanks again, Derrick

 

[steve]

You need to hook up something to replace the MPI part of the relay. A standard Bosch 30A relay will do the trick.

The ECU needs to see battery voltage from whatever your using for an ignition switch on pin 82. It also needs to see battery voltage from the starter switch on pin 71. The relay should get power all the time and the output needs to go to the ECU pins 12 and 15 as well as to the wires that power the MAF, ISC, injector resistor, etc. All the stuff that used to get power from the old MPI relay. The coil for the relay should be connected on one side to the same power as the relay and the other side to ECU pin 38.

You should have the wiring diagram for you car since you were stripping the harness and you need to follow the MFI diagram to connect up what's needed.