Installed a brand new Walbro 255 fuel pump last night, and when I went to restart the car, upon turning the key it failed to crank. I turned the key back and forth and then lost all power - no dash lights, no interior lights, etc. I checked fuses, disconnected the fuel pump, and closed all the doors (the rear door had been open the entire time so I began thinking it could be an immobilizer issue), at which point the interior light came back on. Went to crank with fuel pump still disconnected and I had power again, then reconnected pump and car started right up. I've read the immobilizer disables the fuel pump, not the ignition switch, so doesn't seem to be the culprit. At a bit of a loss but am nervous of the issue repeating itself or there being a hidden short somewhere. Any ideas? Thanks in advance!

 

So I came across this the other night and this might be something for you to look into. There's a common issue with ignitions on evo 8's

Here's a video that explains it. Hope this helps with your issue.