I just want to get my car started, and I have the stock internal harness out of the car, including the fuse box that is under the hood, I have the engine harness just about done so right now I just want to get power to my EMS and turn the car over and make sure it starts/run b/f I continue on.


I have no: ac, heat, blower motor, air bags, interior lights, etc. So im trying to do away with the stock harness that controls all of these items (installing a painless style switch panel) and im also going with a push button start. Maybe someone who has done something simular (i know plenty of you have) can chime in with how they wired up the EMS for power to just run the motor and the OEM guages.

Thank you

 

1313u

 

I have something like what you are doing in my Talon. Custom engine harness but I set it up similar to how the factory did as far as where it gets power for certain things, what goes through the MFI relay, etc. Power for the ECU itself and the MPI relay in both come directly from my ignition switch now. The ignition switch also switches on a painless 7 circuit fuse box to feed the WBO2, etc. Make sure the constant power wire goes to the battery before the cutoff switch or you'll lose your internal log if you shut the car off.

I had some voltage control problems along the way, so my current revision has the alternator voltage sensing wire tired in at the ignition switch so the ECU and all of the related components see full regulated voltage. Voltage at the battery ends up slightly higher which is good for things tied directly to it, like the MSD box.

There are a lot of ways to set this stuff up, and I keep improving my setup constantly after I think it's "done," so whatever you do, make sure it's easy to work on and modify so you can make changes later. I moved the battery to the passenger seat area to make things ridiculously easy to work on, for example.

 

what is the purpose of the MFI relay, isn't it for your fuel system? what does MFI stand for?

Thank you for the information you have provide thus far, much appreciated!

 

MFI/MPI stands for multipoint fuel injection. The relay on DSM at least provides 12 volts for most of the stuff in the engine harness that needs it and is also the fuel pump relay. It also allows the ECU to leave itself on for ~8 seconds after you shut the key off to park the ISC. I Would recomend looking through the MFI and power distribution drawings for the EVO to see how the factory does it, and make changes as necessary to suit your application.

 

MFI, ive herd of MPI but never MFI damn Mitsubishi :/ im gonna take a look at it tonight and see what i come up with.