Electrical nightmare !

I have been having major issues with my 2005 545. It all started when I had a custom exhaust put on. After my install and on the way home the car completely shut off on me . Electrical was all on but the car cut off . Steering hardens up and I cost to the side . Get it towed home and the car starts up fine the next day . Assumed it was a fuel pump on the way out so I replaced it along with sending unit and eveything else that was attached . Still didnt fox the issue. replaced all the fuel related fuses and nothing . changed the green relay in the glove and still nothing . got a tip about the IVM ( integrated supply module) and replaced it since the tech said the board can crack and cause issues . After inspecting it I saw that the 10amp fuse was blown and was led to believe it was indeed a faulty module. car starts up and i thought the problem was resolved. Drove it for a couple months including a 1000 mile caravan round trip to bimmerfest 2013 ! Car dies once I get home . Check the IVM and once again the 10amp fuse is blown . Replaced it and it was good To go . It now continues to blow . Sometimes It pops instantly when I put in the new fuse . I obviously have a short or something . I can't find where it is since it is not a hard content short . Has anyone here had this issue ? Is it indeed a short ? Please help .

Sorry cliff notes

10 amp fuse in IVM keeps blowing and turning off fuel pump. Can't figure out what it is . I assume its a short somewhere . Before having to tear everything apart I was wondering if anyone has had this issue or if anyone had suggestions how I should go about truly diagnosing and repairing this .

 

That 10 amp fuse protects the following:
Fuel pump relay, tailpipe flap, radiator shutter solenoid, E-box fan, DMTL pump and secondary air pump relay.

I suppose since you had your exhaust replaced a logical place to start would be the tailpipe flap.

Reference post #8 in attached for explanation as to its function.
understanding the exhaust valves opening ?